Redox-controlled reversible micelles transition and lyotropic liquid-crystalline behavior of novel polymerizable ferrocenyl surfactants

Abstract

A novel photopolymerizable surfactant with ferrocenyl group, (11-ferrocenylundecyl) (ethyl methacrylate) dimethylammonium bromide (I+), was synthesized through the reaction of 11-bromoundecyl ferrocene and N,N-(dimethylamino) ethyl methacrylate. Based on the results of voltammetric cycle, the small potential difference ΔE was 72 mV, which indicates that the I+ has good redox reversibility. The critical micellar concentration (CMC) values were about 0.5 and 22.7 mM for I+ in the reduction (CMCred) and oxidation state (CMCox) and it could aggregate and disaggregate by using redox reaction and photopolymerization when its concentrations was between their CMCred and CMCox values. The lyotropic liquid-crystalline properties of I+ in water were investigated by X-ray diffraction (XRD) and plarized optical microscope (POM). The results indicate when the concentration of the I+ solution over 40 wt %, an ordered lamellar liquid crystal structure was formed. With increasing concentration, the nanoscopic long-range order improved. Moreover, the lyotropic liquid-crystalline properties of I+ could also be controlled by using redox reaction and photopolymerization. In a word, the novel polymerizable ferrocenyl surfactants are good environmental responsive materials and can potentially act as the drug carrier and the scavenger for removing dissolved organic impurities in water.