Aggregation states and polymerizabilities of amphiphilic monomer molecules in aqueous systems with different water contents

Molecular aggregation states of sodium and zinc 10-undecenoates in aqueous systems with different water contents were investigated in relation to their polymerizabilities. The aggregation states were examined by thermal analysis, and γ-ray-initiated post-polymerization in various states was monitored by IR spectral changes. In the case of sodium 10-undecenoate, coagel and gel states with lamellar structures and a liquid crystal state consisting of a regular hexagonal array of cylindrical aggregates of the molecules can appear, depending on the temperature in the range of water contents of 30–60%. However, zinc 10-undecenoate exhibits coagel, gel-I, gel-II and lamellar liquid crystal states in a wide range of water contents. The polymerizability of the sodium salt increased in the order coagel, gel and liquid crystal with a hexagonal structure, whereas the zinc salt polymerized most effectively in the gel-I phase with a regular lamellar structure. It is concluded that the regular arrangement of the monomer molecules together with conformational freedom is an important factor for the polymerization.