Body temperature-responsive two-way and moisture-responsive one-way shape memory behaviors of poly(ethylene glycol)-based networks

In this work, crosslinked shape-memory polymer networks were prepared by thermally induced free-radical polymerizations of methacrylate-terminated poly(ethylene glycol) (PEG) and n-butyl acrylate (BA), which integrate thermal-responsive two-way and moisture-responsive one-way shape memory effects (SME). Broad molecular weight distributions of PEG were employed with the aim of tuning the transition temperatures close to that of the human body and achieving a broad transition temperature range. The resultant PEG-2,4,10 kDa and PEG-2,6,10 kDa networks showed good thermal- responsive two-way reversible shape memory effects between the human body temperature and 0 degrees C, with the two-way recovery ratios of 8.2% and 6.2%, respectively. Furthermore, the crosslinked networks were found to be moisture-responsive and the deformed specimen was nearly recovered to the original shape (98% in the recovery ratio) when exposed to the moist atmosphere. These features, along with the inherent biocompatible properties, have great potential in biomedical applications.