ASSOCIATION PROBABILITIES BETWEEN THE SINGLE-CHAIN AMPHIPHILES INTO ABINARY MIXTURE IN PLAN MONOLAYERS (II)

A test system of homologous binary mixtures of single-chain amphiphile s was considered. The dependence of the association probabilities on t he hydrophobic chain length, and on the dipole moment of the shorter c hain component when the longer chain component has a low dipole moment , was studied. The free-end effect of each hydrophobic chain on the as sociation probability was also analysed. Generally, both the shorter c hain end effect and the longer chain end effect on the association pro cess are independent of their own initial chain length, but are depend ent on the chain length of the other component and dipole moment. The changes in every association probability produced by the addition of o ne methylene group to the shorter chain and to the longer chain are un equal and opposite. For this reason the efficiency ratios were defined and analysed. The thermotropic behaviour of lipid mixtures can be rel ated to association processes.