Cationic surfactants are used for number of stabilization problem and have found many technical application. Application of cationic surfactants include softeners, cosmetic products, electrodicoating and the stabilization agent of adhesive polymer as well as in mining, floating and paper manufacturing. In recent years, new type of amphiphilic molecules have attracted the attention of various research groups. One of these classes is the gemini surfactants, which have two hydrophilic head group and two hydrophobic groups per molecule, separated by spacer. Gemini surfactants can produce lower surface tension than monomeric surfactants at the same concentration. It have lower cmc and have better wetting properties. As industrial technology makes further progress, demand for high performance surfactant are increasing. In response to these demands, novel cationic gemini surfactants have been successfully designed and developed.
In this study, two type cationic gemini surfactants, namely ,-alkane-bis(N-alkanoyl oxyethyl-N,N-dimethyl)-diammonium bromide and N-dodecyl-N,N-dimethyl alkyl ammonium chloride were synthesized. The synthesized product was confirmed by FT-IR and Raman, 1H-NMR spectroscopy. Surface tension of synthesized cationic gemini surfactants were measured by automatic surface tensiometer. The surface activities of pure and mixed systems in aqueous solution such as surface tension, Krafft temperature, foaming power, emulsifying, solubilization and cmc have been observed at different mole% of synthesized cationic gemini surfactant and sodium dodecyl sulfate (SDS) solution. The cmc of cationic gemini surfactants decreases as the alkyl chain length increases. The cmc values are 0.86 × 10-5∼9.3 × 10-4 mol/L. From the graph of surface tension versus logC, we can determined the critical micelle concentration and surface excess concentration (Γmax) at the air/aqueous solution interface, critical packing parameter (CPP) and the minimum area per surfactant molecule (A) could be calculated according to Gibbs adsorption isotherm. The cmc of mixed systems were obtained by surface tension on cationic gemini/SDS surfactant mixed micelles in water at different mole fraction of surfactants. The decrease of surface activity is attributed to amount of nonsurface -active aggregates. The approximately 0.5 of mole fraction values (χ1) shows that the cationic gemini/SDS surfactants are interacting by 1:1 molar ratio.
The ,-alkane-bis(N-alkanoyl oxyethyl-N,N-dimethyl)-diammonium bromide of C12 chain length shows good foaming properties and stability of foam. The antifoaming properties of C16 chain length seem excellent. N-dodecyl-N-alkyl-N,N-dimethyl ammonium chloride shows low initial foam value and have good anti foaming properties. Slight synergism of emulsification has been observed at two cationic gemini surfactants. The solubilization property of cationic gemini surfactant/SDS mixture(0.8 : 0.2 mol%) shows better solubilization power than other surfactants mixtures.
Synthesized cationic gemini surfactant, its inhibition effect on corrosion of low carbon steel in 1 M HCl solution was tested by weight loss method. The gemini surfactants have been showed the act as an corrosion inhibitor in 1 M HCl by chemical adsorption on the surface of steel. The inhibition rate increases by increasing concentration of cationic gemini surfactants above the cmc.
The water based emulsion adhesive prepared by non-ionic surfactant and synthesized cationic gemini surfactants. The adhesion properties of emulsion adhesive used non-ionic surfactant with cationic gemini surfactant and those used only non-ionic surfactant were compared.
The solid contents of prepared adhesive were 56.8∼62.1 wt%. Particle size distribution of adhesive were 300~900 nm. The initial adhesive expression rate of adhesive used with non-ionic and Gemini 2 was better than adhesive used non-ionic surfactant. The anti-corrosion rate of prepared adhesive by Gemini 1 have good performance on the iron surface during 48 hour.