Fluid flow and interface motion in gels: A finite-strain theory and its application to a channel flow problem

We present a theory for coupled deformation and liquid permeation in polymer gels, allowing large strains rotations conjunction with sharp interfaces separating regions of high low volume fraction. The is applied to pressure-driven flow through gel-filled rectangular channel, the aim investigating how elastic osmotic properties gel influence resulting process. Apart from streamwise direction pressure drop, process may involve transverse if response allows normal stress acting on plane parallel channel walls be affected by shear same plane. For certain energy densities, including those neo-Hookean Mooney type, takes place exclusively drop. Otherwise, spanwise driven contribution distributed planes also present. In contrast downstream flow, transient accompanied changes composition leading nonuniform distribution across thereby influencing profile. By analyzing instantaneous gel, we determine driving force show that strain-stiffening networks motion interstitial directed inward network spreads outward center toward walls. opposite occurs strain-slackening networks. steady-state response, demonstrate gradient leads distributions chains than can continuous or discontinuous. Discontinuous occur an effective involving attractive interactions are formation fraction separated interfaces. Finally, provide illustrative examples whose responses modeled Gent density Flory–Huggins mixing density, respectively.