Studies On Synthesis And Properties Of Gemini Surfactants

Since the1990s, the novel functional surfactants with the especial moleculestructure have become the focus of attention of researchers. Among the large number ofsurfactant products, some of surfactants have especial properties through introducingthe specific functional groups on the basis of traditional surfactants. However, a numberof surfactants are modified on raw materials without surface activity and naturalmaterial, most of are novel synthetic surfactants with special structure than traditionalsurfactants which have excellent properties and special features, such as Geminisurfactants, Bola surfactants, Crown ethers surfactants and Chelating surfactants and soon.Gemini surfactants are made up of at least two hydrophilic groups and twohydrophobic groups which are connected at the level of the head groups by a spacergroups through chemical bond. Because of their especial structure, Gemini surfactantshave better physical and chemical and applicable properties than conventionalsurfactants, but the price is more expensive, the large-scale industrialization has notachieved. In this paper, we use amino acids and their derivatives because of their widevariety of sources as raw materials, through a series of experiments, the Lysine-basednovel Gemini surfactants were synthesized.The major work are listed below.1． The present status and synthesis situation about different types of Geminisurfactants are reviewed detailedly and simple introductions about current applicationsand development prospects of Gemini surfactantst are summarized.2． Lysine-based Gemini surfactants have been synthesized with hydrophobicchain lengths were8,10,12and their structures were testified by FT-IR and1H-NMR.The optimized conditions of synthesis were determined by discussing the factorsaffecting reactions with taking product yield as index.3． The critical micelle concentration (cmc) and the surface tension (γcmc) at theircmc of Gemini surfactants were measured by Conductivity and Surface tension methods.The impacts of carbon chain length, solution temperature and electrolyte concentrationon cmc value and γcmcvalue of different Gemini surfactants were explored. At the sametime, we discussed other properties of Gemini surfactants, including the properties,wettability, solubilization and emulsification properties.4． The thermal properties, molecular and micelles structure in aqueous solution ofLysine-based Gemini surfactants were studied. Because of their environment friendly, non-toxic and good biocompatibility characteristics, we researched the interactionsbetween Gemini surfactant and DNA.