4D Printing of a Bioadhesive Shape Memory Elastomer

Tissue adhesive materials for biomedical applications demand exceptional stretchability, flexibility, and robust adhesion. Herein, we introduce a bioadhesive shape memory elastomer (SME) that is 4D printed by digital light processing (DLP). The ink for printing this SME consists of N-vinylpyrrolidone (NVP), dodecyl acrylate (DA), and a new Poly(ethylene glycol-co-dodecanedioic acid) diacrylate (AcP) prepolymer. By employing AcP, a linear oligomer with tailored hydrophobic and hydrophilic segments, as a crosslinker, the resulting poly(AcP-DA-NVP) SME exhibits impressive mechanical and adhesion performance. Depending on the weight ratios of the ink precursors, this bioadhesive SME shows tunable transition temperatures in a range of 9-68 °C, Young's modulus of up to 24 MPa, and tensile strength of ~ 18.5 MPa, stretchability of ~ 700%, and adhesion strengths of ~ 600 kPa to dry/wet aluminum foils and 90 kPa to porcine skin. Empowered by these combinational properties, the SME offers an unprecedent capability of being a shape-programmable, adhesive substrate for on-skin soft electronics and shows potential for tissue engineering, wound healing, and biomedical implantation.