Formation of crystal nuclei near critical supersaturation in small volumes.

This work deals with the nucleation of crystals in confined systems in response to the recent high interest in research on crystallization in emulsion and microemulsion droplets. In these confined systems, crystallization often occurs at high supercooling; thus, nucleation determines the overall crystallization process. A decrease in the volume of the confined mother phase leads to the higher supercooling needed for the phase transition. We have numerically solved kinetic equations in order to determine the conditions under which the first crystal nuclei are formed by homogeneous and heterogeneous nucleation from supercooled melt and supersaturated solution, depending on the volume of the mother phase. Supersaturation (or supercooling) increases with decreasing volume of the mother phase. The nucleation barrier depends linearly on the logarithm of volume of the mother phase in all cases under consideration, as follows from the numerical solution of kinetic equations.