The relationship between the molecular structure of polyhydroxy amphiphiles and their aggregation behaviour in water. I. The contact preparation method as a tool for empirical studies

The lyotropic liquid‐crystalline behaviour of several dozens of (nonionic) 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 aqueous solution. The compounds were plotted as a function of the total number of hydroxyl and carbonyl groups vs. the total number of carbon atoms in the (hydrophobic) alkyl chain(s). The symbol used for each compound was chosen to indicate the mesophase observed. In this manner, a clear picture emerged of the relationship between overall molecular structure and type of lyotropic phase(s) formed. Based on this plot it becomes possible to predict the type of lyotropic phase that will be formed at the amphiphile‐water interface. Lyotropic mesophases are generally considered to be built up from the aggregates found in dilute aqueous solution. Therefore, a contact preparation also constitutes a simple test for the prediction of the type of aggregate an amphiphile will form in dilute aqueous solution. A useful tool for the design of new surfactants is thus provided.