Drozdov A D, deClaville Christiansen J
Center for Plastics Technology, Danish Technological Institute, Gregersensvej 7, Taastrup 2630, Denmark.
Department of Mechanical and Manufacturing Engineering, Aalborg University, Fibigerstraede 16, Aalborg 9220, Denmark.
J Chem Phys. 2015 Mar 21;142(11):114904. doi: 10.1063/1.4914924.
A model is developed for the elastic response of a polyelectrolyte gel under unconstrained and constrained swelling in a water bath with an arbitrary pH, where a monovalent salt is dissolved. A gel is treated as a three-phase medium consisting of an equivalent polymer network, solvent (water), and solute (mobile ions). Transport of solvent and solute is thought of as their diffusion through the network accelerated by an electric field formed by mobile and fixed ions and accompanied by chemical reactions (self-ionization of water molecules, dissociation of functional groups attached to polymer chains, and formation of ion pairs between bound charges and mobile counter-ions). Constitutive equations are derived by means of the free energy imbalance inequality for an arbitrary three-dimensional deformation with finite strains. Adjustable parameters in the governing relations are found by fitting equilibrium swelling diagrams on several hydrogels. The effects of pH, ionic strength of solution, and constraints on equilibrium water uptake are studied numerically.
建立了一个模型，用于描述聚电解质凝胶在任意pH值且溶解有单价盐的水浴中无约束和有约束溶胀时的弹性响应。凝胶被视为由等效聚合物网络、溶剂（水）和溶质（移动离子）组成的三相介质。溶剂和溶质的传输被认为是它们通过网络的扩散，这种扩散由移动离子和固定离子形成的电场加速，并伴随着化学反应（水分子的自电离、聚合物链上连接的官能团的离解以及结合电荷与移动反离子之间离子对的形成）。通过有限应变下任意三维变形的自由能不平衡不等式推导出本构方程。通过拟合几种水凝胶的平衡溶胀图来确定控制关系中的可调参数。数值研究了pH值、溶液离子强度和约束对平衡吸水量的影响。
