Synthesis of Carbohydrate Derived Non-ionic Gemini Surfactants and Study of Their Micellar and Reverse Micellar Behavior - A Review

Abstract

Gemini surfactants (gemini) are a distinct class of amphiphiles having more than one hydrophobic tail and hydrophilic head group connected via a spacer. These surfactants usually have better surface active properties than corresponding conventional surfactant of equal chain length. Depending upon the nature of charge on head group, these geminis may be cationic or anionic. If there is no charge on head group, the geminis are termed as non-ionic. Carbohydrate derived gemini surfactants carry sugar moiety linked with each of the conventional surfactants, which are further connected by spacer. The sugar moiety was found to enhance the aggregation tendencies. Moreover, due to the presence of sugar moiety, these surfactants are non-toxic and biodegradable. Due to chiral nature of sugar moiety, these surfactants can be used for chiral recognition of some chiral drugs in order to improve their aqueous solubility. Non-ionic surfactants are more important than ionic surfactants as in the latter case, due to repulsion among the same charged head group, aggregation does not take place readily. However, in case of non-ionic surfactants, the head group carries no charge, so there is no repulsion, thus micelle forms easily and at low concentration. The only repulsive forces among head groups are due to hydration shell formed by solvent molecules.