Abstract
We examine the shape memory effect in polymer networks intended for biomedical, and specifically cardiovascular, applications. The polymers were synthesized by photopolymerization from a tert‐butyl acrylate monomer with a diethyleneglycol diacrylate crosslinker. Three‐point flexural tests were used to systematically investigate the thermomechanics of shape storage (predeformation) and shape recovery. The glass transition temperature, T~g~, of the polymers was determined to be approximately 65°C. The polymers show 100% strain recovery, at low and high predeformation temperatures, up to maximum strains of ∼80%. The polymers show a sigmoidal free strain recovery response as a function of increasing temperature at a constant heating rate. Free strain recovery was determined to depend on the temperature during predeformation; lower predeformation temperatures (T < T~g~) decreased the temperature required for free strain recovery. Constrained stress recovery shows a complex evolution as a function of temperature and also depends on the temperature during predeformation. Stress recovery after low‐temperature predeformation (T < T~g~) shows a peak in the generated recovery stress, whereas stress recovery after high‐temperature predeformation (T > T~g~) is sigmoidal. The isothermal free strain recovery rate was found to increase with increasing temperature or decreasing predeformation temperature. The thermomechanical results are discussed in light of potential biomedical applications, and a prototype device is presented. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 339–348, 2005