Multistage Reversible Tg Photomodulation and Hardening of Hydrazone-Containing Polymers

The glass transition temperature (T-g) of a series of polyacrylate- and polymethacrylate-based polymers having bistable hydrazone photoswitches as pendants increases upon photoisomerization. The ensuing photohardening of the polymeric network was corroborated using nanoindentation measurements. The bistability of the switch allowed us to lock-in and sustain multiple T-g values in the same polymeric material as a function of the hydrazone switch's Z/E isomer ratio, even at elevated temperatures.

Automated summary

The glass transition temperature (T-g) of polyacrylate- and polymethacrylate-based polymers with bistable hydrazone photoswitches increases after photoisomerization. The study used nanoindentation measurements to confirm the photohardening of the polymeric network. The bistability of the switch allows the material to maintain multiple T-g values based on the Z/E isomer ratio of the hydrazone switch, even at elevated temperatures.