Highly Tough Hydrogels with the Body Temperature-Responsive Shape Memory Effect

Abstract

Shape memory hydrogels (SMHs), a promising class of smart materials for biomedical applications, have attracted increasing research attention owing to their tissue-like water-rich network structure. However, preparing SMHs with high mechanical strength and body temperature-responsiveness has proven to be an extreme challenge. This study presents a facile and scalable methodology to prepare highly tough hydrogels with a body temperature-responsive shape memory effect based on synergetic hydrophobic interactions and hydrogen bonding. 2-Phenoxyethyl acrylate (PEA) and acrylamide were chosen as the hydrophobic monomer and the hydrophilic hydrogen bonding monomer, respectively. The prepared hydrogels exhibited a maximum tensile strength of 5.1 ± 0.16 MPa with satisfactory stretchability, and the mechanical strength showed a strong dependence on temperature. Besides, the hydrogel with 60 mol % PEA shows an excellent body temperature-responsive shape memory behavior with almost 100% shape fixity and shape recovery. Furthermore, we applied the hydrogels as a shape memory embolization plug for simulating vascular occlusion, and the embolism performance was preliminarily explored in vitro.