Conventionally, solid-solid reactions have been treated using models similar to solid-fluid reactions. However, in general, we need to explicitly account for the discrete nature of contact between reactants in such cases (and hence the complicated geometries that arise when reactions proceed from such contact points), since the conventional treatment often leads to inconsistent values for the rate parameter estimated (Diffusivity in most cases). We have derived approximate models to treat such situations and also derived some conditions under which the conventional treatment may suffice. In ongoing work, we are trying to rigorously solve the problem using a finite-element technique, and hence establish the regions in the parameter space where different approximations are tenable. The models are also being tested via experiments on calcia-alumina and other systems.

Several gas-separation membranes and RO membranes are made by polymerization techniques in which the conditions of synthesis have a significant influence on the structure, and hence function, of the membrane. Interfacial polycondensation is a reaction that is actively being investigated in our group. Novel methods have been developed to follow the kinetics of these fast reactions and relate them to the structural features of the films that form. Other themes such as performance enhancement through particle incorporation are additional areas of interest.