Recent ucb_chemistry_cbme_oapdeposits items

Processing-Dependent Structure and Poroelasticity of Nafion in Liquid Water

Thu, 25 Jun 2026 00:00:00 +0000

Ionomers act as the solid polymer electrolyte membrane in many modern electrochemical devices, yet the role of their nanostructure in modulating the poroelastic response remains poorly understood, especially in liquid water, where few techniques can measure simultaneous transport-mechanical properties. Poroelastic Relaxation Indentation (PRI) is uniquely suited for measuring time-dependent transport-mechanical properties of porous solids, specifically hydraulic diffusivity, elastic modulus, Poisson’s ratio, and intrinsic permeability, for porous solids. While ionomers such as Nafion are not porous in the typical sense, Nafion has a nanophase-segregated structure that, when fully swollen in liquid water, behaves as a poroelastic solid with a coupled mechanical-transport response. Using a poroelastic framework, we investigate how casting and pretreatment of Nafion membranes alter their poroelastic response in liquid environments. We characterize both extruded and dispersion-cast...

Predicting Particle-Size Distributions in Fuel-Cell Inks

Thu, 25 Jun 2026 00:00:00 +0000

Prediction of the catalyst-activated carbon particle sizes of fuel-cell inks remains a critical challenge in enhancing the performance and durability of fuel cells. The performance and structural integrity of the catalyst layers in the cell depend not only on the properties of the ionomer, but also on the carbon supports that host the catalyst. To investigate how these carbon aggregate structures form, we present a model that calculates the cooperative size distributions of ionomer and carbon aggregates in various water/alcohol mixtures and compares those results to available experimental data. Aggregation of both the suspended ionomers and the carbon particles is interwoven as the carbon aggregation depends heavily on the ionic strength of its environment, namely protons dissociating from the ionomer’s sulfonic-acid-group side chains. We demonstrate that the surrounding mixed solvent as well as NafionTM binder concentration strongly influence the degree of aggregation for carbon...

Geometric phase detection via NMR interferometry

Mon, 22 Jun 2026 00:00:00 +0000

We introduce a benchtop NMR method for interferometric detection of geometric phase (also known as Berry/Aharonov-Anandan phase) via spin coherence holonomy in bulk ensembles using phase-wound echo trains. Consecutive π pulses with cyclic phase incrementation drive closed spinor trajectories on the Bloch sphere, while a parity-based analysis isolates the geometric contribution and cancels dynamical offsets by comparing positive and negative winding experiments with a zero-winding reference. The extracted phase increases linearly with echo number, reverses sign under winding reversal, and is independent of echo time in the adiabatic regime, consistent with spinor holonomy arising from parallel transport. Experiments performed in strongly inhomogeneous, low-field conditions demonstrate robustness to B₀ gradients and diffusion. This approach establishes a practical foundation for probing geometric phase effects in NMR, with extensions to non-adiabatic transport, heterogeneous systems,...

Understanding the Cathode Electrochemistry of Humidified Solid‐State Lithium‐Oxygen Batteries

Thu, 18 Jun 2026 00:00:00 +0000

Abstract Lithium‐oxygen batteries (LOBs) possess a high theoretical energy density, making them potential candidates for next‐generation energy storage. However, challenges such as reactive oxygen species‐induced component degradation hinder their practical use. Inorganic solid‐state electrolytes offer an alternative to degradation‐prone aprotic electrolytes, while also protecting lithium anodes from potential atmospheric reactants. This study explores the cathode electrochemistry of solid‐state LOBs using humidified oxygen, which forms an aqueous catholyte during initial cycling, thereby improving cathode‐electrolyte contact. To quantitatively analyze the cathode electrochemistry, a ‘Humidity‐Incorporated’ Differential Electrochemical Gas Monitoring System (HiDEMS) is developed to control humidity and monitor gas consumption and evolution in real time. When studying a Li‐O 2 cell that employs a NASICON‐type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) solid electrolyte and a porous...

Beyond the Pre‐Equilibrium Approximation: Consequences of Elementary Step (Ir)reversibility on the Mechanistic Interpretation of Tafel Slope

Tue, 16 Jun 2026 00:00:00 +0000

The relationship between electrochemical potential and reaction rate-or Tafel slope-is fundamental to the study of multi-step charge transfer reactions. However, despite its importance and ubiquitous use, Tafel slope is seldom interpreted outside of "cardinal" values. The mechanistic interpretation of cardinal Tafel slopes is predicated on the pre-equilibrium approximation (PEA): that the path between the (catalyst) resting state and rate-determining step is in equilibrium. This stringent approximation severely limits opportunities to elicit mechanistic information from electrochemical processes. In this Scientific Perspective, we broaden the existing framework for mechanistic interpretation of Tafel slope through a simple, universal equation that generally describes Tafel slope in terms of elementary-step symmetry factors and approach-to-equilibrium (i.e., approach to PEA accuracy). The predictiveness and mechanistic utility of these theoretical developments are showcased through...

How Does Water Dissociation Work in Bipolar Membranes?

Wed, 10 Jun 2026 00:00:00 +0000

Bipolar membranes (BPMs) create counteracting spatial gradients of pH and electrostatic potential in electrochemical systems, enabling applications in pH regulation, electrocatalysis, and separations. At the polarized junction of a BPM the water dissociation (WD, 2H₂O ⇌ H₃O⁺ + OH^-) reaction can be driven, but it remains poorly understood. In this Perspective, we integrate molecular insights from bulk-water autoionization and the associated field effects with continuum descriptions of BPM electrostatics and experimental WD kinetic analyses to describe possible mechanisms of voltage-driven WD. Pristine BPM junctions highlight both the limits of primarily electric-field-driven WD and the practical challenges of junction stability at extreme reverse bias. Introducing heterogeneous catalyst layers, commonly metal oxides and graphene oxides, accelerates WD by orders of magnitude through hypothesized coupled effects in which surface acid-base...

Polyolefin blends with co-continuous architectures enabled by dynamic covalent crosslinking

Wed, 10 Jun 2026 00:00:00 +0000

Blending polymers produces brittle materials due to macrophase separation and poor interfacial adhesion, which is exemplified by mixtures of polyolefins. This presents a formidable challenge for the mechanical recycling of mixed plastic waste. Here, we demonstrate that dynamic covalent crosslinking of immiscible polyolefin blends creates macrophase separated co-continuous architectures, yet they display excellent mechanical properties, which challenges the conventional wisdom regarding morphology-property relationships in polymer blend compatibilization. We find that the position and orientation of dynamic crosslinks and their influence on crystallinity are key to understanding the structure-morphology-property relationships. In particular, high-resolution microscopy imaging reveals alignment of crystallite planes with strong orientational preference, particularly at polymer-polymer interfaces, which contribute to material performance. We further demonstrate that changes in crosslinker...

Correction: Sustainable bioproduction of the blue pigment indigoidine: Expanding the range of heterologous products in R. toruloides to include non-ribosomal peptides

Mon, 25 May 2026 00:00:00 +0000

Correction for ‘Sustainable bioproduction of the blue pigment indigoidine: Expanding the range of heterologous products in R. toruloides to include non-ribosomal peptides’ by Maren Wehrs et al. , Green Chem. , 2019, 21 , 3394–3406.

Colloidal stability and aggregation of polyethylene (PE) nanoplastics under UV weathering and PFOA contamination

Fri, 22 May 2026 00:00:00 +0000

The colloidal stability of polyethylene nanoplastics (PE NPs) impacts their environmental fate. UV weathering and pollutant adsorption modify the surface of nanoparticles, alter particle-particle interactions and, in turn, modulate their colloidal stability. This study reports on the colloidal stability of 200 nm PE NPs as a function of salt concentration and surface treatment. Colloidal stability is determined for the as made particles, after UV weathering, and in the presence of perfluorooctanic acid (PFOA). Aggregation kinetics is determined using dynamic light scattering and zeta potentials. The surface properties of the PE NPs are characterized using FT-IR spectroscopy, tensiometry, and adhesion measurements. Pristine PE NPs are colloidally stable in dispersions below ∼0.1 mol L^-1, but rapidly aggregate at higher salt concentrations. Environmental modifications have contrasting effects on PE NP stability. The presence of PFOA does not significantly impact the overall...

Stress-aided thermal activation of crack propagation in multidentate hydrogen bonding adhesives.

Fri, 22 May 2026 00:00:00 +0000

Adhesives containing multidentate hydrogen bonding moieties are gaining prominence for their ability to adhere strongly underwater. Previous studies attributed their remarkable underwater adhesion to the multiple adjacent attachment points within a moiety stabilizing the bond, enabling cooperative hydrogen bonding. However, as adhesion involves multiple coupled phenomena, isolating the contribution of individual bonds to the adhesive strength remains challenging. Here we investigate the relationship between peeling velocity and adhesion over a range of temperatures to estimate the activation energy of the chemical bonds that fracture at the adhesive interface. We utilize a model epoxy modified by the addition of tridentate hydrogen bonding moieties (DGEBA-Tris). We report on the effect of curing, debonding temperature, and crack velocity on the adhesive strength at the DGEBA-Tris/mica interface. Adhesion is measured using self-arrested crack propagation to probe the threshold...

Leveraging a synthetic biology approach to enhance BCG-mediated expansion of Vγ9Vδ2 T cells

Thu, 14 May 2026 00:00:00 +0000

There is an urgent need to develop a more efficacious anti-tuberculosis vaccine as the current live-attenuated vaccine strain BCG fails to prevent pulmonary infection in adults. In this study, we leverage a synthetic biology approach to engineer BCG to produce more (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), an intermediate of bacterial-but not host-isoprenoid biosynthesis via the methylerythritol phosphate (MEP) pathway. HMBPP strongly activates and expands Vγ9Vδ2 T cells, which are unique to higher-order primates and protect against Mycobacterium tuberculosis infection. BCG has been engineered to produce specific ligands and antigens to some success; in contrast, our strategy exploits a self-nonself recognition mechanism in the host via HMBPP sensing, which has not been attempted before. To inform the design of our recombinant strains, we performed synteny analyses of >63 mycobacterial species and found that isoprenoid biosynthetic genes are not operonic across...

Out-of-time-order correlators bridge classical transport and quantum dynamics

Thu, 14 May 2026 00:00:00 +0000

The out-of-time-order correlator (OTOC) has emerged as a central tool for quantifying decoherence across wide-ranging physical platforms. Here, we demonstrate its direct measurement in a classical ensemble using nuclear magnetic resonance with a modulated gradient spin echo sequence and extend the method into a multidimensional correlation to track exchange phenomena. Position is encoded through magnetic field gradients and momentum through the velocity autocorrelation function, enabling experimental access to OTOCs for proton motion confined within the self-similar lattice of the metal-organic framework MOF-808. Here, water confined to specified geometries within the MOF pores gives rise to spatially distinct diffusive eigenmodes with characteristic relative entropies. We demonstrate that periodic radio frequency driving combined with gradient modulation yields entropy evolution through the selection of distinct diffusion modes. Frequency-resolved diffusion spectra connect these...

Operation-Induced BiVO4 Surface Reconstruction Modulates Photoelectrochemical Glycerol Photooxidation Stability and Activity

Thu, 7 May 2026 00:00:00 +0000

Operation-Induced BiVO4 Surface Reconstruction Modulates Photoelectrochemical Glycerol Photooxidation Stability and Activity

Oxygen-tolerant CO 2 capture using protected redox-driven reverse bias bipolar membrane electrodialysis

Wed, 6 May 2026 00:00:00 +0000

Electrochemical methods for carbon capture potentially have the advantage of low cost and low energy consumption. The practical applicability of pH-swing carbon capture processes driven by proton-coupled redox-active molecules has been limited by the sensitivity of reduced molecules to oxidation by O2. In those CO2 capture processes, the molecules are reduced, basifying the electrolyte; the electrolyte containing the reduced molecules is exposed to air or flue gas containing CO2 but also containing enough O2 to oxidize the molecules. O2 sensitivity would not be problematic if the electrolyte that captures CO2 contains the oxidized form of the molecule instead; this can be accomplished by switching from an electron-driven system to an ion-driven system. We report the development and performance of a two-chamber flow cell incorporating a reverse-bias bipolar membrane (BPM) and non-proton-coupled redox-active molecules for ion-driven pH-swing. When using ferri/ferrocyanide electrolytes...

Quantitative Dissection of Agrobacterium Virulence to Generate a Synthetic Ti Plasmid

Fri, 24 Apr 2026 00:00:00 +0000

Agrobacterium is not only a costly plant pathogen but is also an essential tool for plant transformation. Though Agrobacterium-mediated transformation (AMT) has been heavily studied, its polygenic nature and complex transcriptional regulation make identification of the genetic basis of transformational efficiency difficult through traditional genetic and bioinformatic approaches. Here, we use a bottom-up synthetic approach to systematically engineer the tumor-inducing plasmid (pTi), wherein the majority of virulence machinery is encoded. Using a validated toolkit to control Agrobacterium gene expression in planta, we perform a quantitative dissection of AMT to investigate the contributions of critical vir-genes at different expression levels. We construct a synthetic pTi capable of transient plant and stable fungal transformation and characterize bottlenecks and solutions for complex polygenic synthetic pTi designs. Our reductionist approach...

Synergistic ruthenium single-atom and nanoparticles in nickel as cooperative catalysts for the alkaline hydrogen evolution reaction

Thu, 23 Apr 2026 00:00:00 +0000

Efficient hydrogen evolution reaction (HER) catalysts that reduce the use of noble metals and can be synthesized on a large scale are essential for advancing anion exchange membrane water electrolyzers (AEMWEs) toward commercialization. Herein, we present a composite catalyst in which Ru nanoparticles coexist with Ru single-atom alloys (SAAs) dispersed within Ni nanoparticles (Ru-SAA/Ni), creating a highly active HER electrocatalyst. Using a one-pot and scalable synthesis method, we can tune the material composition from SAA, i.e. materials containing atomically dispersed Ru atoms (with ≤0.4 at% Ru) to composite structures in which SAAs coexist with Ru NPs. Comprehensive characterization using XPS, XAS, and TEM confirms Ru-SAA formation at a low Ru content and composite structures at higher contents. Electrochemical evaluations conducted in a three-electrode setup reveal that Ru-SAA/Ni composites achieve HER performance on par with that of Pt/C. Computational insights suggest...

Foundation models for atomistic simulation of chemistry and materials

Wed, 22 Apr 2026 00:00:00 +0000

Conventional computational methods for modeling chemical and materials systems are limited by system size and timescale, forcing a trade-off between quantum-mechanical accuracy and the sampling needed for realistic observables. Large language and vision foundation models — pre-trained on massive datasets using transformer architectures — have revolutionized many fields. It is thus interesting to ask whether a foundation model — subject to suitable data, parameter scaling and training — could enable learned simulations of chemistry and materials. Here, we review the field of machine-learned interatomic potentials (MLIPs) and posit that scaling up large and diverse chemical and materials datasets and highly expressive architectures using advanced training strategies should result in models that are: more efficient, transferable, robust to out-of-distribution scenarios, and easier to fine-tune to a variety of downstream physical observables than models trained from scratch on...

Local pH control for impure-water-fed bipolar-membrane electrolyzers

Wed, 22 Apr 2026 00:00:00 +0000

Local pH control for impure-water-fed bipolar-membrane electrolyzers

Polymer‐Assisted Supercooled Lithium Salts: Nonflammable Single‐Ion Conducting Liquid Electrolytes for Next‐Generation Batteries

Tue, 21 Apr 2026 00:00:00 +0000

ABSTRACT Electrolytes that exhibit both high ionic conductivity and a near‐unity Li + transference number ( t Li ) are essential for next‐generation rechargeable batteries. Here, we present solvent‐free liquid electrolytes based on polymer‐assisted supercooled lithium salts that realize single‐ion conduction under ambient conditions. A trace amount of poly(methyl methacrylate) suppresses crystallization, stabilizing low‐melting Li salts in a deeply supercooled liquid state while retaining t Li ≈ 1. To further enhance ion transport, we employ a dual‐salt strategy, which lowers the glass transition temperature and increases ionic conductivity without compromising the near‐unity t Li . Despite moderate conductivity compared with conventional electrolytes, these supercooled salts suppress concentration overpotentials and support stable cycling in Li/LiCoO 2 cells. The intrinsic adhesive properties of the electrolytes enable the fabrication of binder‐free thick cathodes with high...

Out-of-contact peeling caused by elastohydrodynamic deformation during viscous adhesion

Fri, 10 Apr 2026 00:00:00 +0000

We report on viscous adhesion measurements conducted in sphere-plane geometry between a rigid sphere and soft surfaces submerged in silicone oils. Increasing the surface compliance leads to a decrease in the adhesive strength due to elastohydrodynamic deformation of the soft surface during debonding. The force-displacement and fluid film thickness-time data are compared to an elastohydrodynamic model that incorporates the force measuring spring and finds good agreement between the model and data. We calculate the pressure distribution in the fluid and find that, in contrast to debonding from rigid surfaces, the pressure drop is non-monotonic and includes the presence of stagnation points within the fluid film when a soft surface is present. In addition, viscous adhesion in the presence of a soft surface leads to a debonding process that occurs via a peeling front (located at a stagnation point), even in the absence of solid-solid contact. As a result of mass conservation, the...

Dynamics of Irreversible Particle Adsorption to Fluid Interfaces

Fri, 10 Apr 2026 00:00:00 +0000

Understanding the dynamic adsorption of colloidal particles at fluid interfaces is essential for applications ranging from emulsion stabilization to interfacial assembly of functional materials. Adsorption dynamics is often described through diffusion-limited models (such as the Ward-Tordai framework) along with assuming dynamic equilibrium between the adsorbed and dispersed particles. However, most experiments show that particle adsorption is irreversible, and diffusion-limited models fail as the surface coverage goes beyond the dilute limit where particle crowding limits further adsorption. Here, we present a unified model that captures the transition from diffusion-limited to kinetic-limited regimes by coupling diffusion with a Random Sequential Adsorption (RSA)-based boundary condition that accounts for irreversible adsorption and particle blocking for a spherical droplet. Using both a microtensiometer and pendant drop tensiometry, we measure dynamic interfacial tension changes...

Droplet Formation and Growth Mechanisms in Reaction-Induced Spontaneous Emulsification of 3‑(Trimethoxysilyl) Propyl Methacrylate

Fri, 10 Apr 2026 00:00:00 +0000

Spontaneous emulsification of 3-(trimethoxysilyl) propyl methacrylate (TPM) can produce complex and active colloids, nanoparticles, or monodisperse Pickering emulsions. Despite the applicability of TPM in particle synthesis, the nucleation and growth mechanisms of TPM emulsions are still poorly understood. We investigate droplet formation and growth of TPM in aqueous solutions under quiescent conditions. Our results show that in the absence of stirring the mechanisms of diffusion and stranding likely drive the spontaneous emulsification of TPM through the formation of co-soluble species during hydrolysis. In addition, turbidity and dynamic light scattering experiments show that the pH modulates the growth mechanism. At pH 10.1, the droplets grow via Ostwald ripening, while at pH 11.5, the droplets grow via monomer addition. Adding surfactants [Tween, sodium dodecyl sulfate (SDS), or cetyltrimethylammonium bromide] leads to <100 nm droplets that are kinetically stable. The growth...

Distinct Contributions of Particle Adsorption and Interfacial Compression to the Surface Pressure of a Fluid Interface

Fri, 10 Apr 2026 00:00:00 +0000

Particle-laden interfaces stabilize emulsions and foams and can serve as a platform for multiscale materials. Favorable wetting of a particle to a fluid interface reduces the apparent interfacial tension through area replacement with a linear relationship between the apparent surface pressure and the particle area fraction. The area replacement model is widely employed, often up to particle area fraction reaching the maximum hexagonal packing. However, data directly supporting the area replacement model are limited, and the description ignores contributions from particle-particle interactions and does not describe the surface pressure during the compression of a particle-laden interface. This work reports on the direct validation of the area replacement model through the direct measurement of the adsorption energy, surface pressure, and area fraction of adsorbed particles. Experiments combining tensiometry and confocal imaging during the adsorption of colloidal particles to the...

Cooperative Tridentate Hydrogen-Bonding Interactions Enable Strong Underwater Adhesion

Fri, 10 Apr 2026 00:00:00 +0000

Multidentate hydrogen-bonding interactions are a promising strategy to improve underwater adhesion. Molecular and macroscale experiments have revealed an increase in underwater adhesion by incorporating multidentate H-bonding groups, but quantitatively relating the macroscale adhesive strength to cooperative hydrogen-bonding interactions remains challenging. Here, we investigate whether tridentate alcohol moieties incorporated in a model epoxy act cooperatively to enhance adhesion. We first demonstrate that incorporation of tridentate alcohol moieties leads to comparable adhesive strength with mica and aluminum in air and in water. We then show that the presence of tridentate groups leads to energy release rates that increase with an increase in crack velocity in air and in water, while materials lacking these groups do not display rate-dependent adhesion. We model the rate-dependent adhesion to estimate the activation energy of the interfacial bonds. Based on our data, we estimate...

Interface Stabilization in Adhesion Caused by Elastohydrodynamic Deformation

Fri, 10 Apr 2026 00:00:00 +0000

Interfacial instabilities are common phenomena observed during adhesion measurements involving viscoelastic polymers or fluids. Typical probe-tack adhesion measurements with soft adhesives are conducted with rigid probes. However, in many settings, such as for medical applications, adhesives make and break contact from soft surfaces such as skin. Here we study how detachment from soft probes alters the debonding mechanism of a model viscoelastic polymer film. We demonstrate that detachment from a soft probe suppresses Saffman-Taylor instabilities commonly encountered in adhesion. We suggest the mechanism for interface stabilization is elastohydrodynamic deformation of the probe and propose a scaling for the onset of stabilization.

Silver Nanoparticles Mediated by Costus afer Leaf Extract: Synthesis, Antibacterial, Antioxidant and Electrochemical Properties.

Mon, 6 Apr 2026 00:00:00 +0000

Synthesis of metallic and semiconductor nanoparticles through physical and chemical routes has been extensively reported. However, green synthesized metal nanoparticles are currently in the limelight due to the simplicity, cost-effectiveness and eco-friendliness of their synthesis. This study explored the use of aqueous leaf extract of Costus afer in the synthesis of silver nanoparticles (CA-AgNPs). The optical and structural properties of the resulting silver nanoparticles were studied using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infra-red spectrophotometer (FTIR). TEM images of the silver nanoparticles confirmed the existence of monodispersed spherical nanoparticles with a mean size of 20 nm. The FTIR spectra affirmed the presence of phytochemicals from the Costus afer leaf extract on the surface of the silver nanoparticles. The electrochemical characterization of a CA-AgNPs/multiwalled...

Green Synthesis of Ag/Ag₂O Nanoparticles Using Aqueous Leaf Extract of Eupatorium odoratum and Its Antimicrobial and Mosquito Larvicidal Activities.

Mon, 6 Apr 2026 00:00:00 +0000

The health challenges associated with pathogens and ectoparasites highlight the need for effective control approaches. Metal nanoparticles have been proposed as highly effective tools towards combatting different microbial organisms and parasites. The present work reports the antimicrobial and larvicidal potential of biosynthesized Ag/Ag₂O nanoparticles using aqueous leaf extract of Eupatorium odoratum (EO). The constituents of the leaf extract act as both reducing and stabilizing agents. The UV-VIS spectra of the nanoparticles showed surface plasmon resonance. The particle size and shape of the nanoparticles was analysed by transmission electron microscopy (TEM). The larvicidal study was carried out using third and fourth instar Culex quinquefasciatus larvae. The mosquito larvae were exposed to varying concentrations of plant extract (EO) and the synthesized nanoparticles, and their percentage of mortality was accounted for at different time intervals of 12 h and...

Heteroleptic Metal Complexes of a Pyrimidinyl Based Schiff Base Ligand Incorporating 2,2-Bipyridine Moiety: Synthesis, Characterization, and Biological Studies.

Mon, 6 Apr 2026 00:00:00 +0000

A sequence of transition metal complexes of Mn(II), Co(II), Ni(II), and Cu(II) incorporating a novel pyrimidinyl based Schiff base ligand, 2-(4,6-dimethylpyrimidin-2-ylamino)naphthalene-1,4-dione (HL) and 2,2-bipyridine has been synthesized and characterized using elemental, magnetic, conductance, infrared (FT-IR), nuclear magnetic resonance (¹H- and ¹³C-NMR), electronic (UV-Vis), electrospray ionization mass spectrometry (ESI-MS), thermographic analysis (TGA), and molecular docking studies. The acquired results were consistent with the adoption of the chemical formula, [M(X)(L)(Y)]·nH₂O (where M = Mn, Co, Ni, and Cu; L = Schiff base; X = 2,2-bipy; Y = OAc; and n = 0,1) for the metallic complexes. HL ligand acts as a bidentate chelator and coordinates to metallic ion centre through carbonyl oxygen atom and deprotonated imide nitrogen. Similarly, 2,2-bipy acts as a non-ionic bidentate chelator coordinating to metallic ion center via...

Experiments and Calculation on New N,N-bis-Tetrahydroacridines.

Mon, 6 Apr 2026 00:00:00 +0000

Tetrahydroacridines arouse particular interest due to the potential possibilities of application in the medical field and protection against corrosion. Bis-tetrahydroacridines were newly synthesized by Pfitzinger condensation of 5,5-(ethane-1,2-diyl) diindoline-2,3-dione with several cyclanones. NMR, MS, and FT-IR were used to prove their molecular structure. In addition, a computer-aided study was performed for the lowest energy conformers of each structure, in vacuum conditions, at ground state using DFT models to assess their electronic properties. UV-Vis and voltammetric methods (cyclic voltammetry, differential pulse voltammetry, and rotating disk electrode voltammetry) were used to investigate their optical and electrochemical properties. The results obtained for these π-conjugated heteroaromatic compounds lead to the conclusion that they have real potential in applications in different fields such as pharmaceuticals and especially as corrosion inhibitors.

Microstructure of amide-functionalized polyethylenes determined by NMR relaxometry

Tue, 31 Mar 2026 00:00:00 +0000

Amidation of polyethylenes creates a range of amide-containing materials with enhanced properties, but the effect of these functional groups on the microstructure of these new materials is not known. Here we employ solid-state nuclear magnetic resonance (NMR) techniques to analyze the microstructure of amide-modified polyethylenes. While a decrease in crystallinity was observed with increasing amounts of functionalization, we found by measuring the chain mobility of the crystalline, amorphous, and interphasial regions of the polyethylenes with NMR relaxation techniques that the grafted amidyl groups partition into the rigid amorphous fraction (RAF) between the crystalline and amorphous regions. The chemical specificity of these NMR experiments creates precise assessments of the location of functional groups within the materials. Together, these insights into the microstructure and morphology of amide-containing polyethylenes lay a foundation for a deeper understanding of the structure...

Conductivity-Driven Origin of the Limiting Current in Concentrated Electrolytes

Fri, 27 Mar 2026 00:00:00 +0000

Next-generation electrolyte materials are hindered by their ability to support high currents essential for fast-charge and high-power battery applications. The maximum current supported by an electrolyte, the limiting current, is dictated by the formation of concentration gradients across the electrolyte under an electric field. Most of the literature attributes the onset of the limiting current in concentrated electrolytes to the salt concentration at the positive electrode approaching the solubility limit. Here, we leverage operando X-ray transmission imaging to measure spatiotemporal salt concentration profiles of a polymer electrolyte in a lithium–indium symmetric cell at a current exceeding the limiting current. The measurement of concentration profiles enables mapping the spatiotemporal electric potential, which comprises an ohmic contribution, governed by conductivity, and an overpotential related to maintaining concentration gradients. We find that a precipitous drop in...

Spectroelectrochemical Studies of Oxygen Evolution Reaction Kinetics for Surface-Incorporated Iron in Nickel Oxyhydroxide Electrocatalysts

Wed, 25 Mar 2026 00:00:00 +0000

Ni _x Fe_1-x O _y H _z is the state-of-the-art catalyst for the oxygen evolution reaction (OER) in alkaline water electrolyzers; however, understanding the impact of Fe on the active sites, reaction mechanism, and consequently intrinsic activity has been under intense debate. In this work, operando UV-vis spectroscopy was used to investigate Fe-free NiO _x H _y and NiO _x H _y with Fe selectively incorporated onto the surface. At oxygen-evolution potentials, similar oxidized nickel states were present before and after the Fe incorporation, with negligible changes in their redox potentials. However, the discharge kinetics of the Ni states show a substantial acceleration after the introduction of Fe, consistent with an increase in OER kinetics upon Fe incorporation and formation of active Ni-Fe species. Using optical spectroscopy, we determined...

Measuring pH inside a bipolar membrane junction

Wed, 25 Mar 2026 00:00:00 +0000

The local pH environment within bipolar membrane (BPM) junctions is complex and not well understood, yet it is important to control for advancing performance BPM-based electrochemical systems. We report a voltammetric strategy using an ultrathin Ni mesh pH probe to spatially resolve pH variations in the BPM junction during model BPM electrolyzer operation. Under reverse bias, we observe depletion of OH⁻ at the anion-exchange layer (AEL) interface, with the degree of acidification diminishing with increasing distance from the AEL. These gradients correlate with current-dependent water dissociation (WD) and are modulated by the electric field and the surface charge state of the catalyst. By correlating spatial pH profiles with the surface-charging behavior of WD catalysts, we explore a mechanism of catalyst-mediated H⁺ and OH⁻ transfer facilitated by hydrogen-bonding networks. These findings highlight the role of local chemistry and electrostatics in BPM performance and offer new...

Atomic-Scale Imaging Reveals Polar‑π Interactions in Two-Dimensional Molecular Superlattices

Wed, 25 Mar 2026 00:00:00 +0000

Controlling coassembly of synthetic oligomers into binary superlattices at the atomic level is challenging. We report a strategy for programming polar-π interactions in oligomeric peptoids, a class of sequence-defined peptidomimetics, facilitating the formation of homogeneous two-dimensional (2D) superlattices. N-2-phenylethyl and N-(2-perfluorophenyl)ethyl side chains, similar in size, but with contrasting electrostatic characteristics, were introduced at defined sequence positions to generate favorable dipolar aromatic interactions. The resulting nanosheets exhibit different crystal motifs depending on the side chain interactions: systems containing only one type of aromatic side chain form a parallel V-shaped motif driven by π-π interactions, whereas a combination of both types of aromatic side chains, either within one backbone or through the coassembly of two distinct peptoids, adopt an antiparallel V-shaped superlattice with higher thermal stability, driven...

Feedstock-efficient conversion through hydrogen and formate-driven metabolism in Escherichia coli

Tue, 24 Mar 2026 00:00:00 +0000

Product yields for biomanufacturing processes are often constrained by the tight coupling of cellular energy generation and carbon metabolism in sugar-based fermentation systems. To overcome this limitation, we engineered Escherichia coli to utilize hydrogen gas (H₂) and formate (HCOO^-) as alternative sources of energy and reducing equivalents, thereby decoupling energy generation from carbon metabolism. This approach enabled precise suppression of decarboxylative oxidation during acetate growth, with 86.6 ± 1.6 % of electrons from hydrogen gas (via soluble hydrogenase from Cupriavidus necator H16) and 98.4 ± 3.6 % of electrons from formate (via formate dehydrogenase from Pseudomonas sp. 101) offsetting acetate oxidation. Hydrogen gas supplementation led to a titratable and stoichiometric reduction in CO₂ evolution in acetate-fed cultures. Metabolomic analysis suggests that this metabolic decoupling redirects carbon...

AI‐Guided Co‐Optimization of Advanced Field‐Effect Transistors: Bridging Material, Device, and Fabrication Design

Wed, 18 Mar 2026 00:00:00 +0000

The continued miniaturization of field‐effect transistors (FETs) has reached a stage where geometric scaling alone can no longer deliver the necessary performance, power, and area improvements of nanoelectronic circuits. This article presents a forward‐looking, AI‐guided framework for the co‐optimization of advanced FETs, integrating data‐driven materials discovery, physics‐informed device modeling, and multiscale fabrication design. We conceptually decompose FET development into three tightly coupled domains—material design, device design, and fabrication design—and discuss how emerging machine learning, generative modeling, and physics‐informed surrogate models could enable more agile, data‐driven exploration and design within each. We further discuss the potential of hierarchical reinforcement learning to orchestrate cross‐level decision‐making and efficiently navigate the high‐dimensional, nonconvex design landscape inherent to advanced transistor technologies. The proposed...

Gerischer Electrochemistry Today

Fri, 13 Mar 2026 00:00:00 +0000

Semiconductor photoelectrochemistry is a dynamic and interdisciplinary field at the forefront of research in solar fuels, energy conversion, and catalysis. This Perspective captures the collective insights from the second Gerischer Electrochemistry Today Symposium, held at Colorado State University in Fort Collins, CO, in August 2024, which convened leading researchers, early-career scientists, and industry partners to define the critical next steps for the field. Through interactive sessions, technical talks, panel discussions, and training initiativesincluding a Semiconductor Electrochemistry Bootcampthe symposium emphasized three pillars of advancement: (i) facilitating the exchange of new ideas in semiconductor electrochemistry and charge separation; (ii) fostering the development of future researchers, research topics, and participation in the semiconductor workforce; and (iii) building community. This Energy Focus distills key themes from the meeting and identifies major...

Nanoporous Fe2O3 and Soluble Fe(II) Intermediates Accelerate the Electrodeposition of Fe in NaOH(aq)

Thu, 12 Mar 2026 00:00:00 +0000

Electrochemical conversion of iron oxide to iron metal can enable low-cost batteries for long duration energy storage and zero-emissions ironmaking for steel. Iron oxides, such as hematite, can be electrochemically reduced to metallic iron in concentrated alkaline electrolytes at modest temperatures, but the relative influences of solid-state and dissolved intermediates at practical reaction rates remains unclear. Here we prepare a homologous set of well-defined hematite particles to measure how the nanoscale morphology of oxides controls both their reactivity and apparent reduction mechanism in concentrated hydroxide. Correlated electron microscopy and rotating-ring-disk-electrode measurements revealed that nanoporous hematite and solid intermediates formed iron via a dissolution-redeposition pathway. In contrast, dense hematite particles directly formed iron metal via reactive fracture. While previous studies on iron electrowinning have primarily emphasized the role of particle...

Reactivity of Cyclic and Linear Alkyl Carbonates with Reactive Oxygen Species

Tue, 10 Mar 2026 00:00:00 +0000

Electrolyte decomposition at the positive and negative electrodes remains a major challenge to improving lithium-ion battery lifetime. At the positive electrode, chemical oxidation of alkyl carbonate solvents by reactive lattice oxygen species (ROS) has emerged as a key degradation pathway, but the specific reactivity of different solvents toward various ROS and the underlying mechanisms remain unclear. Here, we examine the reactivity of four widely used alkyl carbonates (EC, DMC, EMC, and DEC) with singlet oxygen, peroxide, and superoxide. Gas evolution measurements were used to assess the extent of reactions, and mass spectrometry and NMR spectroscopy identified the resulting products to elucidate reaction pathways. EC was reactive toward all three ROS, with the highest reactivity for superoxide, followed by peroxide and singlet oxygen. Identified products enabled a proposed mechanism for EC oxidation, supported by DFT calculations. In contrast, the linear carbonates (DMC, EMC,...

Isolation of a Terminal Cobalt Nitride in a Metal–Organic Framework

Thu, 5 Mar 2026 00:00:00 +0000

Transition metal nitrides are reactive intermediates in biological and industrial processes. Chemists have synthesized molecular model complexes of such reactive species to understand their function and electronic requirements for new applications. However, molecular chemistry can suffer from intra- and intermolecular decomposition pathways, which preclude further discovery of unknown reactive species. Metal-organic frameworks offer an opportunity for creating long-lived forms of such species with the vacuum of the pore suppressing degradation while simultaneously enabling substrate access for controlled reactivity studies. Here, we report the characterization of an elusive terminal cobalt nitride species generated through photolysis or thermolysis of a site-isolated cobalt azide within the evacuated metal-organic framework CoN₃-MFU-4l. The first crystal structure of such a species is presented, with vibrational, X-ray absorption, and electron paramagnetic resonance...

Automated Strain Construction for Biosynthetic Pathway Screening in Yeast

Tue, 3 Mar 2026 00:00:00 +0000

Automation accelerates the Design-Build-Test-Learn (DBTL) cycle for synthetic biology; however, most strain construction pipelines lack robotic integration. Here, we present the workflow design and source code for a modular, integrated protocol that automates the Build step in Saccharomyces cerevisiae. We programmed the Hamilton Microlab VANTAGE to integrate off-deck hardware via its central robotic arm, enabling automated steps that increased throughput to 2,000 transformations per week. We developed a user interface with the Hamilton VENUS software to support on-demand parameter customization. As a proof of concept, we screened a gene library in an engineered yeast strain producing verazine, a key intermediate in the biosynthesis of steroidal alkaloids. Our pipeline rapidly identified pathway bottlenecks and genes that enhanced verazine production by 2.0- to 5-fold. This technical note provides resources for synthetic biologists designing yeast workflows for biofoundries...

Measuring pH Changes Inside a Bipolar Membrane Junction

Fri, 27 Feb 2026 00:00:00 +0000

The local pH environment within bipolar membrane (BPM) junctions is complex and not well understood, yet it is important to control for advancing the performance of BPM-based electrochemical systems. We report a voltammetric strategy using an ultrathin Ni mesh pH probe to spatially resolve pH changes in the BPM junction during model BPM electrolyzer operation. Under reverse bias, we observe depletion of OH– at the anion-exchange layer (AEL) interface, with a degree diminishing with increasing distance from the AEL. These gradients correlate with current-dependent water dissociation (WD) and are modulated by the electric field and the surface charge state of the catalyst. By correlating spatial pH profiles with the surface-charging behavior of WD catalysts, we explore a mechanism of catalyst-mediated H+ and OH– transfer facilitated by hydrogen-bonding networks. These findings highlight the role of local chemistry and electrostatics in BPM performance and offer new methods to probe...

Synthesis of phosphorus-containing HZSM-5 zeolite particles: Control of phosphorus incorporation through a hydrophobic external-surface Shell

Wed, 25 Feb 2026 00:00:00 +0000

Selective blocking of external surface HZSM-5 zeolite (Si/Al of 11.5) silanol sites followed by impregnating the zeolite with phosphate leads to changes in the zeolite acidity and catalytic performance for n-butane cracking. A monolayer of organosilane capping the zeolite external surface by chemisorption of 3-cyanopropyldimethylchlorosilane formed a hydrophobic shell consisting of 0.36 cyano groups/nm2. Partial hydrolysis of the shell by wetting of the zeolite by water allowed tuning of the transport/chemical reaction tradeoff during aqueous impregnation of the zeolite with phosphate, facilitating efficient distribution of the phosphorus in the internal pore space. The procedure led to a higher degree of framework aluminum retention and a higher total Brønsted acid-site density than was observed with phosphorus-modified HZSM-5 prepared by conventional aqueous wet impregnation. Correspondingly, the phosphorus-modified catalyst had a higher activity for n-butane cracking than the...

Enzymology and Structural Basis of Glycosyltransferases Involved in Saponin C28 Carboxylic Acid O‑d‑Fucosylation

Tue, 10 Feb 2026 00:00:00 +0000

Saponins are a class of natural products composed of an oxidized triterpene core adorned with glycosylations, ultimately giving rise to medicinally important compounds bearing bioactivity that includes, but is not limited to, anti-inflammatory, antimicrobial, antifungal, antiarrhythmic, and immunostimulatory activities. QS-21 is a prominent immunostimulatory saponin and is a critical adjuvant component of several FDA-approved vaccines. One linchpin modification in the biosynthesis and bioactivity of several saponins, including QS-21, is O-d-fucosylation via an ester linkage. In QS-21, the C28-COOH O-d-fucose residue is part of a linear oligosaccharide that is an integral component of the "core pharmacophore" responsible for its immunomodulatory activity. In this work, we performed in-depth in vitro enzymological characterization of two glycosyltransferases involved in C28-COOH O-d-fucosylation during the maturation of two saponin natural products: QsFucT from...

Electric-field enhanced water-dissociation catalysis on oxide surfaces

Mon, 2 Feb 2026 00:00:00 +0000

Water-dissociation-catalyst surface chemistry controls the electrostatic environment within the bipolar membrane, impacting local fields, reaction trajectory, and resultant BPM performance. Ion-transfer reactions in the presence of electric fields are ubiquitous in (bio/electro)chemical systems and catalysis, yet the impact of the electric field is poorly understood. Here, we use bipolar membranes (BPMs) to isolate electric-field-driven non-faradaic water dissociation (WD: H 2 O → H + + OH − ) on catalytic surfaces. We find the catalyst layer's ionic properties dictate both the transport and kinetic processes within the BPM. The role of these properties are explored via a series of membrane architectures, and catalyst poisoning experiments, and the corresponding current–voltage and impedance responses. Arrhenius analyses show that an acidic graphene-oxide (GO x ) catalyst layer gives rise to low interfacial H 2 O entropy in the heterojunction, illustrated via a >100 fold increase...

Engineering CoO x ‑Based Self-Supported Anodes for Pure-Water-Fed Anion-Exchange-Membrane Electrolysis

Mon, 2 Feb 2026 00:00:00 +0000

Commercial membrane electrolyzers rely on acidic fluorocarbon membranes and ionomers, requiring the use of expensive IrO x -based oxygen-evolution catalysts. Anion-exchange-membrane water electrolyzers (AEMWEs) operate in an alkaline environment, enabling the use of non-precious-metal catalysts. Here, we study and engineer CoO x -based catalyst-coated anodes deposited via hydrothermal synthesis directly onto porous transport layers both with and without thermal annealing. The self-supported, nanoneedle-structured Co3O4 anode, formed by annealing the as-synthesized cobalt carbonate hydroxide, Co(CO3) x (OH) y , outperforms the baseline Co3O4 nanoparticle ink-based anode in pure-water-fed AEMWE due to the improved catalyst-layer continuity and thus number of electroactive Co species. The as-synthesized and unannealed Co(CO3) x (OH) y , however, appears to undergo substantial conversion to a more-active CoO x (OH) y phase predominantly at the surface, with nominal Co3+ present...

A Simple and Versatile Cell-Free Expression Method for Producing Secondary Metabolites.

Thu, 29 Jan 2026 00:00:00 +0000

Secondary metabolites are a major source of natural products with industrially relevant bioactivities. Lysate-based cell-free expression (CFE) is an emerging platform for accelerating the discovery and engineering of these natural products. While Escherichia coli cell extracts are widely used for CFE, Streptomyces extracts are likely to offer a more biochemically compatible environment for their expression. However, current Streptomyces-based CFE systems remain underdeveloped, with protocols that are either strain-specific or not readily scalable. To address these limitations and enable broader access to cell-free natural product biosynthesis, we present a generalizable and simple set of reaction conditions that support high-yield protein expression (180-230 μg/mL) in lysates derived from Streptomyces venezuelae NRRL B-65422 and Streptomyces lividans TK24. Like E. coli-based systems, these extracts enable iterative and pathway-level biosynthesis,...

Minimizing Interfacial Resistance between Polymer Electrolytes and Metal Electrodes Using Applied Current

Thu, 29 Jan 2026 00:00:00 +0000

Reducing the interfacial resistance between different phases in electrochemical systems is crucial for enabling practical applications. In this work, we proposed a process for reducing the interfacial resistance between polymer electrolytes and metal electrodes. Thus far in the literature, the lowest interfacial resistance reported in these systems is 15 Ω·cm2. In this study, assembled and preconditioned symmetric cells with lithium–indium alloy electrodes showed similar values. The current through the cell was increased in steps up to the limiting current. This resulted in a permanent decrease of the interfacial resistance to values as low as 1 Ω·cm2, a value that is comparable to that of optimized lithium-ion batteries. The proposed process is general, and it could be applied to any combination of polymer electrolytes and metal electrodes.

Exact statistics of helical wormlike chains with twist-bend coupling

Mon, 26 Jan 2026 00:00:00 +0000

We present a solution for the Green's function for the general case of a helical wormlike chain with twist-bend coupling and demonstrate the applicability of our solution for evaluating general structural and mechanical chain properties. We find that twist-bend coupling renormalizes the persistence length and the force-extension curves relative to wormlike chains. Analysis of intrinsically twisted polymers shows that incorporation of twist-bend coupling results in the oscillatory behavior in principal tangent correlations that are observed in some studies of synthetic polymers. The exact nature of our solution provides a framework to evaluate the role of twist-bend coupling on polymer properties, such as DNA bound to histones and motivates the reinterpretation of existing biopolymer experimental data.

Two-stage process and strain engineering for continuous bioconversion of CO2 to butanol

Tue, 20 Jan 2026 00:00:00 +0000

The efficient valorization of gaseous C1 feedstocks_, such as CO₂, into liquid fuels presents a significant process engineering challenge. Here, we design and demonstrate an integrated chemostat system for the continuous synthesis of butanol from CO₂ and H₂ in a tandem process. Our system architecture sequentially couples two bioreactors housing complementary microorganisms. The first stage utilizes Sporomusa ovata to produce acetate from CO₂ and H₂ autotrophically, which then serves as the sole carbon source for metabolically engineered Escherichia coli in the second stage. Multi-level metabolic engineering of the biocatalyst resulted in a butanol titer of 422 ± 4 mg L^-1 in batch cultures. The two-stage continuous system serves as a proof-of-concept, producing 4.8 mg L^-1h^-1 of butanol from CO₂ via acetate as an intermediate. While not yet meeting established economic benchmarks,...

A highly active Burkholderia polyketoacyl-CoA thiolase for production of triacetic acid lactone

Thu, 15 Jan 2026 00:00:00 +0000

Triacetic acid lactone (TAL) is a versatile platform chemical traditionally biosynthesized via decarboxylative Claisen condensation by 2-pyrone synthase. However, this route is limited by poor efficiency and dependence on malonyl-CoA. Here, we show that non-decarboxylative Claisen condensation by polyketoacyl-CoA thiolases offers a more efficient alternative. Through mining homologs of a previously reported enzyme from Cupriavidus necator, we identify five thiolases with TAL production activity. One candidate, BktBbr from Burkholderia sp. RF2-non_BP3, exhibits approximately 30-fold higher activity in vitro and supports 30-fold higher TAL titers in Escherichia coli compared to the original enzyme. Fed-batch fermentation achieves titers up to 2.8 g L⁻¹. Structural analysis of BktBbr co-crystallized with CoA esters guides rational engineering to further enhance performance. Our discovery of a highly active thiolase establishes an alternative enzymatic route to produce TAL efficiently,...

Ion Transport in Concentrated Crosslinked Solid Polymer Electrolytes

Wed, 14 Jan 2026 00:00:00 +0000

Crosslinking polymers is a common approach to create mechanically stable solid materials such as polymer electrolytes for lithium batteries. In conventional liquid electrolytes, the solvent molecules move freely to accommodate the field-induced motion of ions. However, in crosslinked polymer electrolytes, the rearrangement of polymer segments is constrained by the deformation limits of the network. Herein, we develop a new transport model that accounts for both the formation of concentration gradients and the elasticity of the electrolyte. The elasticity is incorporated by adding an additional term related to the entropy of crosslinked strands to the electrochemical potential of the salt. The resulting Crosslink Model contains two adjustable parameters: N , the average number of monomers in a strand, and λcrit, the maximum strain the network can sustain. These solid-like constraints produce singularities in the governing transport equations, fundamentally altering the concentration...

Mesh-like structure integrated core-shell-shell nanocomposites for enhanced stability and performance in carbon capture

Wed, 14 Jan 2026 00:00:00 +0000

Carbon capture is essential for mitigating climate change, yet most sorbents struggle to combine high capacity with chemical stability. Here we report core-shell-shell (CSS) nanocomposites that integrate adsorption efficiency with exceptional robustness. The design couples a metal-organic framework (MOF) core, which enriches local CO2 concentration, with a polyamine shell that is reorganized into a porous, ordered network through entanglement with an outer covalent organic framework (COF) shell. This hierarchical architecture enables dual amine functionalization via sequential “click” and Schiff-base reactions, achieving a CO2 uptake of 3.4 mmol g−1 at 1 bar. The COF outer layer also acts as a protective barrier, suppressing humidity interference and doubling cycling stability under simulated flue gas. Remarkably, the nanocomposites maintain structural integrity after one week in strongly acidic (3 M HNO3) or basic (NaOH, pH=14) environments, underscoring their chemical resilience....

Molecular origin of negative lithium transference in electrolytes with star-shaped multivalent anions

Mon, 12 Jan 2026 00:00:00 +0000

Large-scale molecular dynamics simulations illustrate that highly correlated cation–anion motion leads to negative t 0+ on the order of 1 in lithium electrolytes with star-shaped multivalent anions. Large multivalent anions have gained increasing attention for their potential to improve lithium transference in electrolytes. We employ large-scale molecular dynamics simulations based on the Onsager transport framework to investigate ion transport in a lithium electrolyte with star-shaped multivalent anions. The simulations show that t 0+, the cation transference number with respect to solvent velocity, is negative over a wide range of concentration. This is consistent with experimental data reported previously. The simulation-based Onsager transport coefficients reveal that the magnitudes of the cation–cation, anion–anion, and cation–anion correlations are comparable, a signature of highly correlated motion in the electrolyte. Examination of the cation solvation environment indicates...

Mitigating humidity interference in chemiresistive hydrogen sensors through hydrophobic surface functionalization

Thu, 8 Jan 2026 00:00:00 +0000

Chemiresistive gas sensors based on semiconductor metal oxides, such as tin dioxide (SnO₂), are indispensable for detecting and monitoring toxic gases and pollutants, making them critical components in industrial and environmental applications. To enhance their performance, the metal oxides are loaded with noble metals such as palladium (Pd). However, ambient humidity poses a significant challenge to their performance. The presence of adsorbed water molecules on the oxide surface can considerably impair sensor sensitivity and overall performance. To address this issue, in this paper, we report on the application of an ultrathin, hydrophobic layer of hexamethyldisilazane to the surface of a Pd/SnO2 sensor. This study investigates the influence of hydrophobic surface modifications on the metal oxide interface, focusing on their impact on sensor sensitivity and selectivity. The resulting sensor exhibits superior hydrogen sensing capabilities, operating effectively at low temperatures...

Analysis of Small-Angle Neutron Scattering from Blends of Charged and Neutral Polymers Based on Rod–Coil Random Phase Approximation

Tue, 6 Jan 2026 00:00:00 +0000

Blends of charged and neutral polymers are of interest due to potential applications in rechargeable batteries. In this study, concentration fluctuations in blends of charged poly[lithium 3-(methacryloyloxy)propylsulfonyl-1-(trifluoromethanesulfonyl)imide] (PLiMTFSI) and neutral poly(ethylene oxide) (PEO) were investigated by small-angle neutron scattering (SANS). The scattering data were analyzed in the framework of the random phase approximation (RPA). Since ion dissociation can lead to stiffening, the charged polymers were approximated as rods, while the neutral polymers were assumed to be random coils. This approach works reasonably well at low weight fractions of charged polymers. For blends with higher weight fractions of the charged polymer, concentration fluctuations were highly suppressed, resulting in q-independent coherent structure factors that are inconsistent with the rod-coil RPA.

A multiscale investigation of polypropylene glycol polymer upcycling to propionaldehyde via catalytic cracking on acid sites of mesoporous Y zeolites

Fri, 12 Dec 2025 00:00:00 +0000

Multi-scale upcycling of PPG polymer synthesizes propionaldehyde in 95% selectivity & 86% yield. We investigate acid-catalyzed upcycling of PPG polymer, emphasizing crucial features on multiple length scales that span reaction engineering on macroscopic length scales down to zeolite catalyst design on the nanoscale. We modified a previously described semi-batch reactor configuration to minimize coking and enhance recovered selectivities by incorporating rapid quenching of reaction products (instead of slower quenching with a condenser, which facilitates sequential coupling reactions), and decreased the initial carrier-gas residence time in the bed consisting of mixed catalyst and PPG polymer, further reducing the deposition of solid residues in the used catalyst. Our results highlight the importance of tight interfacial contact between the catalyst surface and the initial PPG polymer reactant, which is achieved via a pretreatment that removes adsorbed water, for drastically...

Zeolite‐Based Catalysts for Conversion of Oxygenated Polymer Waste by Positron Annihilation

Fri, 12 Dec 2025 00:00:00 +0000

Abstract Positron Annihilation Lifetime Spectroscopy (PALS) has been employed to investigate the catalysts HZSM‐5 and MESO−Y, which play a pivotal role in catalyzing and upgrading plastics, with a primary focus on oxygenated polymers, thereby transforming existing plastic materials into simpler, higher‐quality value‐added products. In this study, PALS was systematically compared with other complementary analytical techniques. The research outcomes have successfully demonstrated the efficacy of PALS in elucidating the morphology and topology of zeolites at micro/meso‐meter scales. The first experiment focuses on H‐ZSM‐5 zeolite subjected to treatments involving polyurethane and polypropylene. The second experiment delves into H‐ZSM‐5 zeolites with varying Si/Al ratios, both before and after conversion. The third experiment investigates Y zeolites that are surfactant templated to induce meso‐porosity, examining their fresh state as well as their post‐conversion condition. The PALS...

H-ZSM-5 Catalysts for the catalytic upcycling of polypropylene glycol

Fri, 12 Dec 2025 00:00:00 +0000

Without effective management, the steady increase of waste plastics threatens environmental well-being and ecological balance. Plastic up/recycling is a promising solution but has many challenges. In this work, catalytic cracking of polypropylene glycol (PPG) was investigated at varying reaction temperatures of 350–550 °C under nitrogen and steam, using H-ZSM-5 zeolites with different silica-to-alumina (SiO2/Al2O3) ratios of 23:1 and 50:1. The catalysts were assessed through physisorption, chemisorption, solid-state magic-angle spinning nuclear magnetic resonance spectrometry, thermogravimetry, electron microscopy, and positron annihilation lifetime spectroscopy. Extra framework aluminum and Lewis-to-Bronsted acid site ratios were found to play a significant role in the selectivity towards propionaldehyde, where values ∼ 80 % could be reached. In addition, a possible pathway for the PPG cracking reaction was proposed, which may lead to a better understanding of PPG and waste...

Irreversible thermodynamics of curved lipid membranes. II. Permeability and osmosis

Thu, 11 Dec 2025 00:00:00 +0000

We present a theory that combines the framework of irreversible thermodynamics with modified integral theorems to model arbitrarily curved and deforming membranes immersed in bulk fluid solutions. We study the coupling between the mechanics and permeability of a viscous and elastically bendable membrane, and a multicomponent bulk fluid solution. An equation for the internal entropy production for irreversibilities at the membrane is derived, determining the generalized thermodynamic forces and fluxes, from which we identify the deviatoric stress as a novel driving force for permeability. A complete set of equations of motion, constitutive laws, and boundary conditions to model the lipid membrane and bulk fluid system are provided.

Engineering Polyketide Stereocenters with Ketoreductase Domain Exchanges

Mon, 8 Dec 2025 00:00:00 +0000

Polyketide synthases (PKSs) are versatile biosynthetic megasynthases capable of producing a diverse range of natural products with many applications, including in pharmaceuticals. The stereochemical precision of PKSs makes them a powerful tool for engineering tailored, unnatural polyketides; however, modifying the stereocenters of a PKS product while maintaining production levels remains a significant challenge. In this study, we systematically tested and evaluated strategies for ketoreductase (KR) domain exchanges, the domain responsible for setting stereocenters of polyketide products. After first optimizing the method for KR exchanges, we then performed 44 KR domain exchanges on three different PKSs to obtain high production of all four stereoisomers in vivo. By testing both one- and two-module PKS systems, we investigated how downstream modules process intermediates with altered stereochemistry and found that the configuration of the α-substituents was critical for gatekeeping...

Tracking Spatiotemporal Electric Potential in Batteries Using High-Resolution Operando X‑ray Transmission Imaging

Tue, 25 Nov 2025 00:00:00 +0000

The formation of significant concentration gradients across electrolytes in batteries affects the rate at which electrochemical reactions occur. In this work, we use high-resolution operando X-ray transmission imaging to capture spatiotemporal salt concentration profiles c(x,t) in a symmetric cell comprising a polymer electrolyte sandwiched between two lithium–indium alloy electrodes during a constant-current experiment followed by open-circuit relaxation. The decay of open-circuit potential is related to the concentration dependence of the potential across concentration cells, U. We show how operando c(x,t) data can be used to calculate the spatiotemporal electric potential “inside” the polarized electrolyte. We track the spatial- and time-dependent cell potential during the constant-current step and distinguish its two contributions: a concentration overpotential governed by U. and an ohmic contribution governed by ionic conductivity. Over most of the time window, the concentration...

Mapping structures and dynamics with frequency-correlated diffusion exchange

Tue, 25 Nov 2025 00:00:00 +0000

Understanding molecular motion in diffusion-driven complex environments is critical for designing sustainable materials and improving chemical processes. Here, we introduce a multidimensional nuclear magnetic resonance (NMR) method that captures how molecular populations exchange across different dynamic regimes. By extending the modulated gradient spin-echo technique to include frequency-frequency correlations, our approach reveals diffusion pathways that are otherwise obscured in heterogeneous systems. Implemented on a unilateral NMR magnet, the method eliminates gradient pulsing constraints and accesses dynamics in the kilohertz regime. We apply this technique to swelling and acid-catalyzed deconstruction of cross-linked and linear polymers to observe how structural heterogeneity evolves over time. By linking molecular motion to topology and chemical state, we extract physical metrics such as fractal surface dimensionality and reaction wavefront velocity, properties inaccessible...

Advances in the microbial biosynthesis of therapeutic terpenoids

Tue, 4 Nov 2025 00:00:00 +0000

Terpenoid natural products and their derivatives exhibit bioactivity that is utilized in FDA-approved drugs and candidates for future drugs; however, the widespread utilization of terpenoids has been limited by complex, low-yielding native biosyntheses and chemical syntheses. Microbial total/semi-biosynthesis of natural and new-to-nature terpenoids from sustainable feedstocks is scalable and can achieve economically viable cost targets. Herein, this review describes foundational advances in synthetic biology and metabolic engineering as exemplified by efforts to biosynthesize prominent terpenoids (i.e. artemisinin, taxol, vinblastine, QS-21, and cyclopamine) in engineered microorganisms (e.g. Escherichia coli and Saccharomyces cerevisiae). Emerging methods that accelerate microbial biosynthesis campaigns (i.e. automation, machine learning, artificial intelligence, and combinatorial screening) are then discussed.

Durable, pure water–fed, anion-exchange membrane electrolyzers through interphase engineering

Sat, 25 Oct 2025 00:00:00 +0000

Anion-exchange membrane water electrolyzers (AEMWEs) promise scalable, low-cost hydrogen production but are limited by the electrochemical instability of their anode ionomers. We report interphase engineering using inorganic-containing molecular additives that coassemble with ionomer, enabling pure water-fed AEMWEs to operate with a degradation rate <0.5 millivolt per hour at 2.0 amperes per square centimeter and 70°C-a >20-fold durability improvement. Analysis of different additives and ionomers shows that the stabilization mechanism involves cross-links between metal oxo/hydroxo oligomers and ionomers. Under operation, the inorganic additive enriches, forming an interphase near the water-oxidation catalyst that passivates the anode ionomer against continuous degradation while maintaining mechanical integrity and hydroxide conductivity. This additive-based interphase-engineering strategy provides a path to durable AEMWEs that operate without supporting electrolytes and...

Multimodal evaluation of network activity and optogenetic interventions in human hippocampal slices

Wed, 22 Oct 2025 00:00:00 +0000

Seizures are made up of the coordinated activity of networks of neurons, suggesting that control of neurons in the pathologic circuits of epilepsy could allow for control of the disease. Optogenetics has been effective at stopping seizure-like activity in non-human disease models by increasing inhibitory tone or decreasing excitation, although this effect has not been shown in human brain tissue. Many of the genetic means for achieving channelrhodopsin expression in non-human models are not possible in humans, and vector-mediated methods are susceptible to species-specific tropism that may affect translational potential. Here we demonstrate adeno-associated virus–mediated, optogenetic reductions in network firing rates of human hippocampal slices recorded on high-density microelectrode arrays under several hyperactivity-provoking conditions. This platform can serve to bridge the gap between human and animal studies by exploring genetic interventions on network activity in human...

RB-TnSeq elucidates dicarboxylic-acid-specific catabolism in β-proteobacteria for improved plastic monomer upcycling

Tue, 7 Oct 2025 00:00:00 +0000

Dicarboxylic acids are key components of many polymers and plastics, making them a target for both engineered microbial degradation and sustainable bioproduction. In this study, we generated a comprehensive data set of functional evidence for the genetic basis of dicarboxylic and fatty acid metabolism using randomly barcoded transposon sequencing (RB-TnSeq). We identified four β-proteobacteria that displayed robust growth with dicarboxylic acid sole carbon source and cultured their mutant libraries with dicarboxylic and fatty acids with carbon chain lengths from C3 to C12. The resulting fitness data suggested that dicarboxylic and fatty acid metabolisms are largely distinct, and different sets of β-oxidation genes are required for catabolizing dicarboxylic versus fatty acids of the same carbon chain lengths. In addition, we identified transcriptional regulators and transporters with strong fitness phenotypes related to dicarboxylic acid utilization. In Ralstonia sp. UNC404CL21Col...

(2+δ)-dimensional theory of the electromechanics of lipid membranes. II. Balance laws

Mon, 8 Sep 2025 00:00:00 +0000

(2+δ)-dimensional theory of the electromechanics of lipid membranes. II. Balance laws

Anion-Exchange-Membrane Electrolysis with Alkali-Free Water Feed

Mon, 8 Sep 2025 00:00:00 +0000

Hydrogen is a green and sustainable energy vector that can facilitate the large-scale integration of intermittent renewable energy, renewable fuels for heavy transport, and deep decarbonization of hard-to-abate industries. Anion-exchange-membrane water electrolyzers (AEM-WEs) have several achieved or expected competitive advantages over other electrolysis technologies, including the use of precious metal-free electrocatalysts at both electrodes, fluorine-free hydrocarbon-based ionomeric membranes and bipolar plates based on inexpensive materials. Contrasting the analogous proton-exchange-membrane system (PEM-WE), where pure water is circulated (no support electrolyte), the current generation of AEM-WEs necessitates the circulation of a dilute aqueous alkaline electrolyte for reaching high energy efficiency and durability. For several reasons, including but not limited to lower cost of balance-of-plant, lower operating cost and improved device's lifetime, achieving high cell efficiency...

(2+δ)-dimensional theory of the electromechanics of lipid membranes. III. Constitutive models

Mon, 8 Sep 2025 00:00:00 +0000

(2+δ)-dimensional theory of the electromechanics of lipid membranes. III. Constitutive models

Three-Dimensional Crystals Assembled by Linear Oligopeptoids

Thu, 28 Aug 2025 00:00:00 +0000

The rational construction of three-dimensional (3D) crystalline lattices from synthetic short-chain polymers remains a significant challenge due to the lack of inherent driving forces to enable crystal growth in all three dimensions. Here, we report the design of 3D peptoid crystals from linear peptoid hexamers, derived from amphiphilic diblock sequences that typically form crystalline two-dimensional (2D) nanosheets. By removing the amorphous domains and tuning the chain termini, crystalline lamellae up to 500 nm thick were achieved, far exceeding the thickness of typical nanosheets (on the order of a few nanometers). These 3D crystals form via the stacking of unit cells with lattice parameters similar to those in 2D nanosheets, where terminal groups, particularly compact C-terminal moieties, facilitate vertical growth and enhance crystallinity. This study highlights the importance of atomic precision in terminus chemistry for achieving long-range ordering and isotropic crystal...

Multiple Operando Fields Can Identify a Predictive Mass Transport Theory in Electrolytes