Designing triple-shape memory polymers from a miscible polymer pair through dual-electrospinning technique

Recently, multiple-shape memory polymers (SMPs) have attracted a great deal of attention in biomedical applications. Therefore, a series of triple-SMPs were developed by simply blending of two immiscible SMPs exhibiting two distinct transition temperatures, which is required for triple-shape memory (SM) effect. However, fabrication of triple-SMPs from completely miscible polymer pairs using the conventional blending approach is a challenging problem. Because this type of blends consists of one homogeneous phase and thereby exhibit only one transition temperature and dual-SM behavior. To overcome this problem, herein, a novel and versatile strategy is introduced for preparation of phase separated blends from a completely miscible polymer pair, exhibiting triple-SM behavior. Dual-electrospinning technique was utilized to simultaneously electrospin poly(lactic acid) (PLA) and poly(vinyl acetate) (PVAc), as a model miscible polymer pair, to obtain an interwoven polymer composite with two well-separated thermal transitions, as revealed by dynamic mechanical analyze. Consequently, the SM experiments revealed that the electrospun PLA/PVAc composites have triple-SM behavior. Furthermore, incorporation of graphene nanoplatelets into the composite fibers significantly improved the triple-SM properties of samples. Additionally, excellent adherence and spreading of the osteoblasts on the fibrous scaffolds containing graphene were observed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47471.