THE RELATIONSHIP BETWEEN THE MOLECULAR-STRUCTURE OF POLYHYDROXY AMPHIPHILES AND THEIR AGGREGATION BEHAVIOR IN WATER .1. THE CONTACT PREPARATION METHOD AS A TOOL FOR EMPIRICAL-STUDIES

The lyotropic liquid-crystalline behaviour of several dozens of (nonio nic) polyhydroxy amphiphiles was studied by observing the penetration of water into the bulk of a sample of amphiphile on a microscope slide and identifying the mesophases observed at the interface with the aqu eous solution. The compounds were plotted as a function of the total n umber of hydroxyl and carbonyl groups vs. the total number of carbon a toms in the (hydrophobic) alkyl chain(s). The symbol used for each com pound was chosen to indicate the mesophase observed. In this manner, a clear picture emerged of the relationship between overall molecular s tructure and type of lyotropic phase(s) formed. Based on this plot it becomes possible to predict the type of lyotropic phase that will be f ormed at the amphiphile-water interface. Lyotropic mesophases are gene rally considered to be built up from the aggregates found in dilute aq ueous solution. Therefore, a contact preparation also constitutes a si mple test for the prediction of the type of aggregate an amphiphile wi ll form in dilute aqueous solution. A useful tool for the design of ne w surfactants is thus provided.