Multi-stimuli responsive shape memory polymers synthesized by using reaction-induced phase separation

Thermo-induced multishape memory polymers are a growing focus of smart materials because of its promising applications. Multishape memory effect is generally attained by using polymers with broad phase transition and multiphase polymers. The latter is of particular interest for copolymerization and polymer compositing. One requirement has to be fulfilled to achieve multishape memory effect, which is to have two reversible phase transitions. In this study, we report synthesis of polymer composite composed of strong segregated polymers by using reaction-induced phase separation. We demonstrate the method by using polyurethane (PU) and poly(methacrylic acid) (PMAA). With adjusting the weight ratio, the polymer composites exhibit a phase spectrum from phase separation to miscible composite. The composite with PU/PMAA =3:1 demonstrated triple-shape memory effect. Based on the results, we argued the effect of segregation on the shape memory effect for polymer composites. With the addition of PMAA, the polymer composite also exhibits pH/water-induced shape memory effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43534.