Interface thermodynamic roughening

Most polymer pairs are thermodynamically incompatible, in the sense that their free energy of mixing is positive. This does not mean that there is absolutely no interdiffusion at all at the interface between them adjacent to the interface limited interdiffusion occurs, which can be seen as an increasing of the low surface entropy implied by a smooth surface [30-33]. This nanoscale roughening of an interface can increase the adhesion between the polymers. 

Adhesion of thermodynamically incompatible polymers is of current interest because of its implications for developing new multiphase polymer materials and for recycling of mixed plastic wastes. Many elegant experiments have been reported in which various types of copolymer are introduced at the interface as putative compatibilizers. The interface may be strengthened as a result of interdiffusion and roughening on a nanoscale. 

The phenomena described in this chapter centered on interfacial disorder, sometimes liquid like disorder, of both a thermodynamic and dynamic origin, and the redistribution of both the disordered material and impurities at solid-liquid interfaces. Because of the change in the surface structure created by both surface roughening and surface melting, they have a profound influence on the local attachment kinetics, and ultimately on pattern formation in ice crystals. We have a clear picture of several issues, namely (i) that roughening is a crucial aspect of growth anisotropy, and (ii) that inter-facially melted water at subfreezing interfaces is mobile and responds in a thermodynamically consistent and predictable manner. Less clear however are a number of other issues as discussed below. 

---