Strong, Tailored, Biocompatible Shape‐Memory Polymer Networks

TLDR

Shape‑memory polymers are smart materials that can change shape under a predetermined stimulus and are used in biomedical devices and industrial applications. This study evaluates photopolymerized thermoset shape‑memory networks with tailored thermomechanics to link polymer structure to recovery behavior. Methyl methacrylate and poly(ethylene glycol) dimethacrylate are copolymerized to produce networks with independently adjustable glass transition temperatures (56–92 °C) and rubbery moduli (9.3–23.0 MPa). Recovery is dominated by glass transition temperature, with rubbery modulus having little effect on free‑strain recovery but strongly influencing stress generation during fixed‑strain recovery, and the MMA‑co‑PEGDMA networks emerge as a high‑strength shape‑memory biomaterial for device design.

Abstract

Abstract Shape‐memory polymers are a class of smart materials that have recently been used in intelligent biomedical devices and industrial applications for their ability to change shape under a predetermined stimulus. In this study, photopolymerized thermoset shape‐memory networks with tailored thermomechanics are evaluated to link polymer structure to recovery behavior. Methyl methacrylate (MMA) and poly(ethylene glycol) dimethacrylate (PEGDMA) are copolymerized to create networks with independently adjusted glass transition temperatures ( T g ) and rubbery modulus values ranging from 56 to 92 °C and 9.3 to 23.0 MPa, respectively. Free‐strain recovery under isothermal and transient temperature conditions is highly influenced by the T g of the networks, while the rubbery moduli of the networks has a negligible effect on this response. The magnitude of stress generation of fixed‐strain recovery correlates with network rubbery moduli, while fixed‐strain recovery under isothermal conditions shows a complex evolution for varying T g . The results are intended to help aid in future shape‐memory device design and the MMA‐ co ‐PEGDMA network is presented as a possible high strength shape‐memory biomaterial.