Modeling solvent-activated shape-memory behaviors based on an analogy between solvent and temperature

For amorphous polymers, the thermally-activated and solvent-activated shape-memory effect share the same physical mechanism. The programmed shape can be recovered either by increasing the environment temperature above the activation temperature (thermally-activated mechanism) or decreasing the activation temperature below the ambient temperature (solvent-activated mechanism). An equivalent role exists for solvent and heat in activating shape recovery. Based on this assumption, we presented a method to simulate solvent-activated shape-memory behaviors through the widely available models developed for the thermally-activated mechanism. The recovery in the solvent was treated as increasing the temperature of the specimen, while the diffusion of the solvent into the polymer matrix was analogous to heat conduction. The model was employed to simulate the solvent-activated temperature memory effect of Nafion in acetone and ethanol. The model predictions showed good agreement with the experimental results.