Shape-Memory Hydrogels with Switching Segments Based on Oligo(ω-pentadecalactone)

Abstract

We investigated whether dual-shape hydrogels based on crosslinked N-vinyl-2-pyrrolidone can be created, in which oligo(ω-pentadecalactone) (equation image = 2900 g · mol−1, Tm = 89 °C) chain segments contribute to the switching domains. In the obtained hydrogels, the volumetric degree of swelling decreased from 480 to 190% while the E-moduli increased from 0.10 to 0.34 MPa with increasing OPDL content. Furthermore, the equilibrium swollen hydrogels displayed good shape-memory properties with strain fixity ratios above 95% and strain recovery rates above 92%. These shape-memory hydrogels, whose degree of swelling was almost independent of the temperature, might be interesting candidates for various applications such as stimuli-sensitive switches or valves.