SURFACE RESTRUCTURING OF POLYMERIC SOLIDS AND ITS EFFECT ON THE STABILITY OF THE POLYMER WATER INTERFACE

Being endowed with a high degree of surface mobility in comparison with other types of solids, the surfaces of polymeric solids can undergo considerable structural alterations between different environments in order to lower the interfacial free energy with a surrounding medium. Such low interfacial free energy values can adversely affect the stability of the polymeric solid-fluid interface and thus give rise to undesirable effects such as the absorption of the fluid into the solid and/or the dissolution of the solid in the fluid. The above considerations were investigated by a simple contact angle procedure, involving polymeric solid-water interface. The results indicate that the polymeric solid-water interface, which typifies the interface of polymers with most biological environments, does indeed become unstable at very small solid-water interfacial free energy values (caused by the restructuring of the solid in the water environment in this case) and this instability promotes the penetration of water into the polymeric solid and the possible dissolution of the solid in water.