Brush-like elastomers enable programmable control of their non-linear elastic deformation response and viscoelastic properties defined by initially low Young’s modulus (10<sup>2</sup> - 10<sup>5 </sup>Pa) followed by intense strain-stiffening on par with biological tissue. Grafted side chains facilitate the disentanglement of polymer strands and iso-chemical regulation of relaxation time in the absence of leachable plasticizers and tackifiers. This structural control, defined by side chain length and grafting density, permits on-demand property modulation by stimuli catalyzed reconfiguration of the network architecture through labile motifs. Herein, we introduce photolabile groups to facilitate UV-triggered cleavage of brush elastomer side chains, cross-linkers, or backbone. The light-induced decrease of grafting density of the disentangled network leads to the transformation of the solvent-free brush elastomer into a gel along with a significant shift in mechanical properties which will decrease material firmness and drive potential hyperextensibility. Inserting the motif into the crosslinker and backbone would deconstruct the network to melt state upon irradiation which would aid in recyclability. As photo-irradiation can be localized, this work will enable topographic, mechanical photo-patterning of brush elastomers with areas of architecturally programed domains of different softness and firmness.

Photopatterned mechanical properties of brush elastomers

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.