Quantitative Predictions of Shape‐Memory Effects in Polymers

Abstract

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 (ε_max ), and stress (σ_SF at ε_max ). 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.