Entropic elasticity
= Entropic elasticity
Entropic elasticity is a restoring response arising from the reduction of accessible molecular configurations under deformation. For an ideal <freely jointed chain>, weak extension has <free energy> $\Delta\mathcal F=3k_BTR^2/(2Nb^2)$ and <spring constant> $k=3k_BT/(Nb^2)$. The proportionality to <temperature> assumes fixed segment geometry; temperature-dependent <Kuhn length> modifies it.