Hydrophilic Sponges Based on 2-Hydroxyethyl Methacrylate. VI. Effect of Phase Sequence Inversion on the Characteristics of IPN between Sponges and Homogeneous Gels

Abstract

Poly (2-hydroxyethyl methacrylate) (PHEMA) is currently used as a prosthetic polymer in an artificial cornea consisting of a skirt made of a PHEMA sponge attached to a transparent circular core of homogeneous PHEMA hydrogel. Along the interface between components, a gradient IPN was achieved by using PHEMA sponge as polymer I into which the precursor liquid monomer mixture for the central hydrogel diffused significantly prior to polymerization. In this study, the phase sequence was reversed in order to find whether the inversion affects the manufacture of prosthesis. By using the homogeneous hydrogel as polymer I, the diffusion of liquid monomer mixture for the sponge is negligible. As a result, the IPN region along the interface is very narrow and leads to a weak union between prosthetic polymers. The direct phase sequence (in which PHEMA sponge is polymer I) should be exclusively used for the manufacture of such prostheses.