Cross-Linked Shape Memory Polymer Blends with Tunable Heating Rate Sensitivity

An emerging class of smart materials is based on matter that senses and reacts to the kinetics of environmental changes, which were named predictive materials. One example of those are shape memory polymers that retract to different lengths at the same temperature depending on the heating rate toward this temperature. The few known examples are homopolymer systems, such as syndiotactic polypropylene and poly(ethylene terephthalate) that cannot be tuned in the heating rate sensitivity, which limits their applicability. This study reports on cross-linked polymer blends of commercial poly(vinylidene fluoride) (PVDF) and poly(2-ethyl-2-oxazoline) (PEtOx), which were found to have an adjustable melting temperature, crystallinity, and glass transition temperature. Thus, this approach allows to vary the sensitivity range by varying composition and programming by cocross-linking these two polymers.