Crystal Growth of Organic Soft Materials in Template-controlling Systems

Crystallization phenomena of organic soft materials occurring in template-controlling systems such as emulsions, vesicles, micelles and air-water interfaces have been discussed by reviewing recent work. Long-chain molecular crystals and amino acids were chosen as the model substances of the organic soft materials which are key materials in food, pharmaceutical, nuetraceutical, cosmetic, and other bio-related industry. Three template-accelerated crystallization systems have been examined: template films prepared by physical vapor deposition, template films at the water-in-oil and oil-in-water emulsions. In the all systems examined, it was confirmed that the template films accelerated the heterogeneous nucleation whose kinetic and morphological properties are largely different from batch systems without any template acceleration. In particular, the vapor-deposited template films showed the controlling of polymorphism and molecular orientation of the crystallized materials through specific interface interactions. In the emulsion systems, it was assumed that the heterogeneous nucleation is initiated at the emulsion interface through van der Waals interactions which are minimized in the bulk systems.