Polymerization of mixed Langmuir monolayers based on 10,12-pentacosadiynoic compounds

This work reports on the preparation and investigation of ultrathin polymer films based on 10,12-pentacosadiynoic acid and 10,12-pentacosadiynamine. Mixed catanionic Langmuir monolayers formed from these compounds at different component ratios have been studied. It has been established that the electrostatic attraction of the head groups of monolayer components facilitates spreading of the diacetylene monomers over the surface of an aqueous subphase and prevents pentacosadiynoic acid from crystallization. Fiber-optic spectrometry has been employed to study the effect of monolayer packing density on the efficiency of polymerization in the system and to investigate the optical properties of two-dimensional copolymers. It has been shown that the interactions between the oppositely charged head groups in a polymerized monolayer facilitate the formation of a film with a low shrinkage and do not hinder the fast relaxation of the strained blue form of the polymer into its red form characterized by a lower bond conjugation. For the first time, optically uniform ultrathin films based on copolymers of diacetylene surfactants have been obtained and their morphology has been investigated with the help of atomic force microscopy.