Synthesis Of A Gemini Cationic Surfactant Having An Azobenzene Group And The Performance Of The Surfactant Mixture

Gemini surfactants consist of two hydrophilic groups and two hydrophobic chains,which are connected by a spacer group.It has been reported that the interfacial properties of a Gemini surfactant in aqueous media can be orders of magnitude greater than those of the comparable conventional surfactant.Azobenzene compounds are a class of compounds that typically have different isomers under different lights.A cationic Gemini surfactant(AzoBr)having an azobenzene group was prepared,the structure of which was characterized by1 H NMR and IR spectroscopy.The photoisomerization of the surfactant was identifed by UV spectra.The surface activity of the surfactant was carefully measured.The results showed that the surfactant had low critical micelle concentration.The viscoelastic properties of the surfactant were studied by using the sinusoidal oscillations and the interfacial tension relaxations.We studied the relationship between the viscoelasticity and the foam stability of the surfactant.The results show that the surfactant has stable foaming.After UV irradiation,the critical micelle concentration increases and the foam stability decreases.The results of viscoelasticity show that the modulus decreases after UV irradiation.The cationic Gemini surfactant has different relaxation processes at the air/water interface before and after UV irradiation.In order to broaden the application of the surfactant,we studied the solution properties of the surfactant mixture having AzoBr and the dihydroxy stearic acid.The optimum correlation was calculated by the correlation coefficient.We measured the surface tension,foam stability and rheological properties of the complex system.The results show that the combination of the two compounds has better synergistic effect.It shows lower surface tension and cmc values comparing with the single surfactant.Finally,we studied the flotation of quartz using AzoBr as a collector.The flotation mechanism was investigated by measuring the contact angle,floated rate,Zeta potential and adsorption.The experiments show that AzoBr has strong flotation performance for quartz.