UC Riverside

This dissertation explores the design and application of functionalized anthracene derivatives as light-responsive elements embedded in polymeric and crystalline environments. By leveraging the photochemical reactivity of allylidene and azide functional groups, two distinct but complementary material behaviors are demonstrated: reversible light-induced mechanical motion and photochemical gas evolution.In the first approach, an anthracene derivative bearing a photoisomerizable allylidene unit, (E)-3-(3-(anthracen-9-yl)allylidene)-1,5-dioxaspiro[5.5]undecane-2,4-dione (E-ADUD), is used to create submicron-thick crystalline microsheets via surfactant-assisted precipitation. These sheets undergo rapid rolling into microcylinders upon visible light irradiation, driven by localized E→Z photoisomerization at the surface and the resulting interaction from the unconverted isomerization in the crystal interior. Continued irradiation relaxes this strain and causes unrolling, while preserving crystallinity and light responsiveness. This reversible actuation behavior resembles bimorph mechanics and opens pathways to optically triggered deployable microstructures.In the second system, azidoanthracene and related polycyclic azides are incorporated into transparent polymer matrices such as poly(methyl methacrylate) (PMMA), polystyrene, and polycarbonate. Upon exposure to UV or visible light (365–405 nm), these materials rapidly generate nitrogen gas bubbles at the polymer–water interface. The mechanism involves a multistep process of photolysis, gas transport through the polymer, and bubble nucleation. Efficient gas release is achieved through high azide loading, intense illumination, and surface roughness optimization. The resulting surface-adhered bubble layers remain stable underwater for extended periods and significantly enhance ultrasound contrast, enabling potential use in medical imaging and diagnostic applications.Together, these studies illustrate how the design of anthracene-based molecules and their integration into suitable host environments can yield materials that respond dynamically to light through gas release or mechanical transformation. By understanding relationships governing these effects, this work establishes a versatile foundation for light-controlled materials with potential applications in soft robotics, responsive coatings, medical imaging, and microactuation technologies