Water-responsive shape memory PLLA via incorporating PCL-(PMVS-s-PAA)-PCL-PTMG-PCL-(PMVS-s-PAA)-PCL

Poly(L-lactide) (PLLA) was one of the most well-known biodegradable polyesters. Although its thermo-responsive shape memory (SM) function has been studied by proper program, high transformation temperature is not suitable in some biomedical applications. Water-responsive SM polymer is an alternative choice and exhibits great potential because it is harmless to the cells and tissues of organisms. In the work, a novel PCL-(PMVS-s-PAA)-PCL-PTMG-PCL-(PMVS-s-PAA)-PCL copolymer was devised as an additive to endow PLLA with water-responsive SM capability. The incorporated PLLA was characterized by cross-section, water contact angle, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Inserted PTMG segment and assisted ambient temperature were contributed to its SM behaviors. The shape fixation ratio and shape recovery ratio were 92.0% and 94.2%, respectively. The schematic diagram between internal microstructures and macroscopic properties was proposed. At the same time, the incorporated PLLA showed excellent toughness. So the obtained SM material would be promising for medical and biomimetic fields.