OBSERVATION OF OSTWALD-LIKE RIPENING IN 2-DIMENSIONAL CRYSTALLIZATIONOF POLYETHYLENEGLYCOLDISTEARATE IN LANGMUIR-BLODGETT-FILMS

Langmuir-Blodgett films of polyethyleneglycoldistearate obtained from monolayers spread at air-water interfaces have been studied using diff erent spreading solvents. They show that growth patterns in the two-di mensional crystallization at the interface are determined by how far t he film is from the equilibrium when solvents with different polaritie s are used. Single crystals seem to grow when polar solvents such as m ethanol are in the mixture while disordered ramified structures are fo rmed when solutions of the compound in purely nonpolar solvents are ap plied at the water surface. The results indicate that the aggregation and subsequent crystallization are stabilized by polar components simi lar to Ostwald ripening in binary mixtures.