Wetting transitions within membrane compartments

Abstract

A biomimetic membrane in contact with several aqueous phases is theoretically studied using a combination of Helfrich curvature elasticity theory for fluid membranes and self-consistent field theory for polymers in solutions. Two phases that are thermodynamically formed by phase separation of aqueous solutions, as well as stable and metastable shapes of fluid vesicles, have been observed. The wetting transitions from complete to partial wetting and to complete dewetting are identified within a membrane compartment. The dependences of wetting transitions on material parameters, such as the intrinsic contact angles θ_in, the interaction strengths between the polymers χ_αβ and between the membrane and the polymer η_p, and impermeability of the membrane to the enclosed polymers ζ_p, are investigated. For a given χ_αβ, impermeability ζ_p and affinity to the membrane η_p, θ_in is found to be a constant and independent of the reduced volume of vesicles and the volume fraction of two phases.