Nanocapsule Incorporation Strategies to Enhance Polymer Network Properties

Photochemically recyclable polymer networks offer a promising platform for sustainable materials, and embedding nanomaterials into networks provides new pathways to tune mechanical properties. We investigated the incorporation of silica nanocapsules into poly(ethylene glycol) star polymers end-functionalized with anthracene, which undergo reversible [4+4] cycloaddition upon irradiation with ultraviolet light. Nanocapsule concentration and surface functionalization were varied to determine their impact on gelation kinetics, mechanical reinforcement, and recyclability via in situ photo-rheology. Nanocapsules were fabricated with 0%, 25%, or 50% anthracene surface functionalization and incorporated into polymer solutions at 0%, 10%, and 20% v/v. Upon UVA irradiation (365 nm), anthracene-functionalized nanocapsules enhanced network stiffness compared to networks formed with unfunctionalized nanocapsules or neat polymer solutions. In all cases, networks were deconstructed using UVC irradiation (265 nm), demonstrating that silica nanocapsules did not impede recyclability. These results show that incorporating nanomaterials into photo-recyclable polymer networks may improve mechanical properties while maintaining recyclability, advancing efforts to develop sustainable materials.