Modelling the effect of phase behaviour on the deformation in light-activated shape memory polymer blends

Light-activated shape memory polymers (LASMPs) are smart materials that transform back to their intended shape when stimulated by light. Although, unlike traditional SMPs, LASMPs have significantly faster response time and therefore, are enabling materials for a variety of remote actuation and non-invasive applications, their synthesis via chemical route is quite cumbersome. In contrast, blending constituent polymers to synthesize SMPs is straightforward, but their incompatibility leads to the formation of interfaces and thereby, results in inferior mechanical properties. Here, we develop a a non-linear viscoelastic constitutive model that captures the effect of interfacial properties and component miscibility on mechanical deformation in LASMP blends under isothermal conditions. Our investigations reveal that the interfacial stresses between phase-separated domains can be tweaked by manipulating the interfacial energy coefficient and thereby, increasing the mechanical strength of LASMP blends. The advantage of our non-empirical approach is that it provides an efficient pathway to design photo-chemical/thermal LASMPs with tailored properties. Our findings can also be extended to capture the structure-property relationships for other multi-component multi-phase polymer blends.