Development of zwitterionic copolymers with multi-shape memory effects and moisture-sensitive shape memory effects

Shape memory polymers (SMP) and zwitterionic polymers both have great applications in biomedical fields. This works successfully combines functionalities of zwitterionic polymers and SMP, developing new kind of zwitterionic copolymers having a multi-shape memory effect (SME) and a moisture-sensitive SME. The results demonstrate that a series of zwitterionic multi-SMPs, coded as p(DMAPS-co-AA), were synthesized from DMAPS and acrylic acid (AA). A micro-phase separated structure is formed in the resulting p(DMAPS-co-AA). The strong hydrogen bonding between AA segments serves as a reversible switch, while the strong electrostatic forces among DMAPS segments serve as physical crosslinkers. Therefore, shape memory testing demonstrates that p(DMAPS-co-AA) shows not only dual-SME, but also triple-SME and quadruple-sSME. Moreover, in addition to the thermally-induced SME, p(DMAPS-co-AA) also shows moisture-sensitive SME. It is thus proposed that this zwitterionic multi-SMP could find great potential applications in smart biomedical fields.