A theory of constrained swelling of a pH-sensitive hydrogel

• DOI: 10.1039/b917211d
• Publication Date: 2010-01-26T10:00:10Z
• Authors: Romain Marcombe; Shengqiang Cai; Wei Hong; Xuanhe Zhao; Yuri Lapusta; Zhigang Suo
• Keywords: Legendre transformation; Hyperelastic material

Many engineering devices and natural phenomena involve gels that swell under the constraint of hard materials. The causes a field stress in gel, often makes swelling inhomogeneous even when gel reaches state equilibrium. This paper develops theory constrained pH-sensitive hydrogel, network polymers bearing acidic groups, equilibrium with an aqueous solution mechanical forces. condition is expressed as variational statement field. A free-energy function accounts for stretching network, mixing solution, dissociation groups. Within Legendre transformation, hydrogel equivalent to hyperelastic solid. first used compare several cases homogenous swelling: free attached rigid substrate, confined three directions. To analyze swelling, we implement finite element method commercial software ABAQUS, illustrate layer coated on spherical particle, valve microfluidics.