Applications of colloids in studies of phase transitions and patterning of surfaces

Colloidal dispersions mimic almost all phases of condensed matter and serve as excellent model systems. Therefore, studies of 'model' colloids (i.e. particles with tailored surface or geometric properties) under equilibrium and nonequilibrium conditions have helped to provide new insights into phase transitions in atomic systems. Moreover, new phase transitions (such as a homogeneous-->inhomogeneous transition), which do not have any atomic analog, have also been discovered. Further, structural investigations into charged dispersions in confined geometries have revealed attraction between similarly charged particles. This attraction appears to be similar to the effective interaction potential invoked in the literature in an attempt to explain a number of experimental results in bulk systems. Studies on ordering of colloids have also led to an interest in taking advantage of self-assembly of colloidal spheres for fabricating nanostructures and superlattices on solid substrates.