Programming of Temperature-Memory Onsets in a Semicrystalline Polyurethane Elastomer

We demonstrate that phase-segregated poly(ester urethane) (PEU) with crystallizable switching segments of poly(1,4-butylene adipate) (PBA) excels as high-performance temperature-memory polymer. Temperature-memory effects (TMEs) with regard to strain and stress recovering could be programmed by polymer elongation at temperatures below or within the PBA melting transition, followed by cooling under constant stress below the PBA crystallization transition and unloading. Beyond that conventional approach, a novel TME programming route was designed, mostly consisting in specimen elongation and unloading at the same temperature. As a result, an enhanced control over the onsets of strain and stress recovering could be achieved. With these findings, the TME could be exploited to switch quick response (QR) codes in recently developed information carriers from unreadable to readable. We conjecture that such behavior can be programmed into virtually all semicrystalline elastomers and anticipate applicability as label technology to monitor temperature abuse of food and pharmaceuticals.