Solvent Content Controlling Strategy for Cocrystallizable Polyesters Enables a Stress‐Free Two‐Way Shape Memory Effect with Wider Service Temperatures

Abstract It is challenging to enhance the stress‐free two‐way shape memory (stress‐free TWSM) effect to obtain a wide range of response temperatures. Herein, a polycaprolactone (PCL)/poly(ω‐pentadecalactone) (PPDL) is photocured under UV light irradiation in the solvent of 1,1,2‐trichloroethane (TCA), to obtain a series of cross‐linked polyesters (CPES). Controlling solvent content (SC) which is removed after the polymerization allows the yielded CPES to perform a regulatable thermodynamic and stress‐free TWSM properties. High SC is beneficial to reduce the degree of chain overlap (C/C * ) of PPDL chain segments in the PCL‐based CPES network, then causes the cocrystallization of PCL and PPDL and yielding an additional melting‐transitions ( T m ). An enhanced stress‐free TWSM is obtained in high SC samples (CPES‐15‐90), reflected in the attainment of a wide range of response temperature, which means a wider service temperature. The enhancement is reflected in higher reversible strain of high SC samples compared with the samples prepared with low SC when varying high trigger temperature ( T high ). Even at high T high , the high SC sample still has reversible strain. Therefore, controlling SC strategy for photocuring copolyester not only provides a new preparation approach for high‐performance shape memory (SM) polymers, but also offers new condensed polymer structure to explore.