Base-stable amphiphilic diblock copolymers with a polydiallyl dimethyl ammonium hydroxide block were synthesized and characterized to quantify hydroxide-ion transport in the hydrated state; polystyrene was the hydrophobic block. The challenge of synthesizing a copolymer comprising blocks with very different solubility behaviors was addressed by a combination of reversible addition fragmentation chain transfer polymerization and ion metathesis. Both monomers used in the polymerization are commercially available on industrial scales. Hydroxide-ion conductivities of 0.8 mS/cm were achieved in hot-pressed membranes immersed in water at room temperature despite relatively low water uptake (4.2 water molecules per hydroxide ion). The stability of the polydimethyl ammonium hydroxide chains was investigated in 2 M NaOD at 60 °C. 1H NMR spectroscopy studies showed no detectable degradation after 2000 hours. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2243–2248.

Poly[(styrene)-block-((2-acryloxy)ethyltributylphosphonium bromide)] diblock copolymers (STBP) were synthesized in two steps. First, reversible addition-fragmentation chain transfer polymerization was used to synthesize the diblock copolymer precursors poly[(styrene)-block-(bromoethyl acrylate)] (SBEA), followed by functionalization with tributylphosphine. Copolymers with overall molecular weights ranging from 31 to 87 kg/mol were synthesized. The volume fraction of the ion-containing monomers in the copolymers was fixed at about 0.57. Self-assembly of these copolymers into ordered morphologies with tunable domain sizes was demonstrated by small-angle X-ray scattering. The effect of morphology on water uptake and bromide ion conductivity was explored in samples equilibrated in liquid water. The use of the pendant tributylphosphonium cations, which have some hydrophobic character, results in low water uptake and high anionic conductivity. The conductivity increases with increasing domain size while water uptake is unaffected by domain size.

Free-volume of polymers governs transport of penetrants through polymeric films. Control over free-volume is thus important for the development of better membranes for a wide variety of applications such as gas separations, pharmaceutical purifications and energy storage. To date, methodologies used to create materials with different amounts of free-volume are based primarily on chemical synthesis of new polymers. Here we report a simple methodology for generating free-volume based on the self-assembly of polyethylene-b-polydimethylsiloxane-b-polyethylene triblock copolymers. We have used this method to fabricate a series of membranes with identical compositions but with different amounts of free-volume. We use the term artificial free-volume to refer to the additional free-volume created by self-assembly. The effect of artificial free-volume on selective transport through the membranes was tested using butanol/water and ethanol/water mixtures due to their importance in biofuel production. We found that the introduction of artificial free-volume improves both alcohol permeability and selectivity.

Versatile polyelectrolytes with tunable physical properties have the potential to be transformative in applications such as energy storage, fuel cells and various electronic devices. Among the types of materials available for these applications, nanostructured cationic block copolyelectrolytes offer mechanical integrity and well-defined conducting paths for ionic transport. To date, most cationic polyelectrolytes bear charge formally localized on heteroatoms and lack broad modularity to tune their physical properties. To overcome these challenges, we describe herein the development of a new class of functional polyelectrolytes based on the aromatic cyclopropenium ion. We demonstrate the facile synthesis of a series of polymers and nanoparticles based on monomeric cyclopropenium building blocks incorporating various functional groups that affect physical properties. The materials exhibit high ionic conductivity and thermal stability due to the nature of the cationic moieties, thus rendering this class of new materials as an attractive alternative to develop ion-conducting membranes.