Tailoring the Mechanical Behaviour of Light-Activated Polymer Blends

Light-activated polymers (LAPs) are smart materials capable of undergoing shape transformations in response to light, allowing on-demand remote and contactless control with precise spatial and temporal manipulation. Photochemical reactions, like cis-trans isomerization, dimerization, etc., are one of the mechanisms harnessed by LAPs for deformation, which often leads to multi- component/phase system analogous to polymer blends. In this work, we develop a free energy-based framework that integrates the kinetics of phase separation and photochemical reaction with elastodynamics to develop a constitutive model. Using this model, we not only capture the mechanical response of nanoparticle-compatibilized phase-separated binary elastic LAP blends but also establish the design rules for enhancing the material’s susceptibility to mechanical failure under loading conditions. Our approach provides a foundational model for light-activated/thermo-responsive shape memory PBs with potential applications in soft robotics, 4D printing, and material origami.