Ecologically safe sugar-based gemini surfactants

Abstract

Gemini surfactants have appeared in the early 1990s as a new type of surfactants with two polar heads and two alkyl tails linked by an spacer. These structural feature give to these type of surfactants unprecedented and better interfacial properties in comparison with their monomeric counterparts. Alkyl glycosides are monomeric non-ionic surfactants prepared in industrial scale from fatty alcohols and carbohydrates. They are gradually replacing the non-ionic surfactants derived from petrochemical materials. The interesting properties of gemini surfactants prompted us ten years ago to design and synthesize gemini surfactants from alkyl glucoside. Butyl, octyl, dodecyl and tetradecyl glucosides were prepared and linked through O-6 or O-2 via succinyl, glutaryl and terephthaloyl spacers. The effect of the position of the linkage, the anomeric configuration of the glucoside, the spacer functionality and the spacer type (rigid or flexible) on the interfacial properties were analized. The physico-chemical parameters of these gemini surfactants were compared with those of their monomeric conterparts. Synergist effects were studied. Molecular modelling and inverse micelle formation are summarized.