Preparation Of Vesicle Induced By Ca²⁺ And Its Properties

Two series of surfactants based on amino acid are designed and synthesized in this dissertation. The surface properties and foamability are studied and a possible explain is proposed to explain the result. All the products are used to prepare vesicle induced by Ca-through ultrasonic dispersion, and the proper concentrations of amino acid surfactants are determined by dynamic light scattering analysis. The optimal mass ratios of lecithin to surfactants are determined. The influence of acid-soap mixed system on vesicle formation is discussed.Long carbon chain acyl chlorides are obtained by the reaction of octanoic acid, capric acid, lauric acid, myristic acid or palmitic acid with phosphorus trichloride. Then the long carbon acyl chlorides are reacted with glycine in the weak alkaline environment, and the N-long carbon acyl glycine (GlynC) is prepared. The long carbon acyl chlorides are reacted with serine in mixture of water and tetrahydrofuran, and the N-long carbon acyl serine (SernC) is prepared. The two series surfactants, ten compounds, are characterized by MS,1H NMR and13C NMR.Surface properties and foamability of synthesized amino acid surfactants are studied. It can be found that the CMC and ycmc values of the synthesized amino acid surfactants decrease as the length of carbon chain increases in the same series, but the saturated absorption and the molecular sectional area don’t show a big difference among the compounds in the same series. Compared with the glycine series, the serine series appears a higher CMC and a lower ycmc.The trend of the foamability change of the two series is consistent with that of surface tension change. At the same concentration, the serine series shows a better foam stabilization because of the lower surface tension of surfactants and hydrogen bond between two surractant molecules. A better foamability of serine series is observed than that of glycine series.The vesicle induced by Ca2+is studied. For the synthesized compounds, single chain surfactants, Ca2+can induce the surfactants to form vesicle except Gly10C, Gly12C and Ser12C. The optimal concentrations of amino acid surfactants are determined by particle size, the PDI and average size will increase when concentration above or below the optimal concentration. The optimal concentration decreases with the increase of carbon chain length in the same series. Finally, the influences of lecithin and acid-soap mixed system are discussed. The PDI of system decrease when lecithin is added to the mixed solution of amino acid surfactant and Ca2-. Glyl2C and Scrl2C can form vesicle in the acid-soap (1:1) mixed system.