STATISTICAL-MODEL OF SHORT ALCOHOL MONOLAYERS - CHAIN CONFORMATIONS AND MELTING TRANSITION

A mean field statistical model is used to calculate the chain organiza tion and the thermodynamics behavior of an amphiphilic monolayer at th e surface of water. The configurations of a single chain are generated with the rotational isomeric state model chains. In order to obtain s emiquantitative results for comparison with experiments on short alcoh ol monolayers, the model uses as an external input a relation between the average volume per CH2 and the molecular area experimentally deter mined in recent reflectivity measurements. Various properties associat ed with the chain conformations are calculated and compared with molec ular dynamics simulations. The model exhibits a phase transition which is identified with the melting transition of short alcohol monolayers and which clearly underlines the major role of the conformational ene rgy. (C) 1996 American Institute of Physics.