Review on chemically bonded geminis with cationic heads: second-generation interfactants

Cationic gemini surfactants are a special class of second-generation smart surfactants. Since Menger first named them, gemini surfactants have drawn a wide and immense attraction from scientists throughout the whole world. These dimeric surfactants possess two or more hydrophilic with two or more hydrophobic head groups, chemically bonded with a linker, called the spacer group. These kinds of surfactants are used mainly in homogeneous catalytic reactions, as well as for solubilisation, emulsification, and many more technical applications. They are used in industries for electro-decoating, stabilization of adhesive polymer latex, anti-friction agents, mining, paper manufacturing, preparation of surfactants including softeners, cosmetics, and most importantly, recent advancement in drug designing, synthesis, and application in medicine. The aim of this paper is to bring attention to the high performance second generation interfactants, with a focus on their synthesis, structure, types, and greener industrial application with high possibility of future prospect.