Quantitative Predictions of Shape‐Memory Effects in Polymers

Unique shape-memory transitions manifested by directional extension and subsequent retraction in polymers are attributed to stored conformational entropy. This behavior is quantified in terms of stored (ΔS S) entropic energy density, the maximum strain (εmax), and stress (σSF at εmax). This concept allows quantitative assessments of the shape-memory effect (SME) and can be utilized in any material that exhibits a glass-transition temperature (T g) and a rubbery plateau.