The Interaction Between Imidazolium Surfactants And Hydrophobic Modified Polyacrylamide

Imidazolium cationic surfactants are a kind of amphiphilic molecules, which are made of imidazolium rings as head groups and alkyl chains as the hydrophobic parts. Imidazolium surfactants have some unique properties different from other cationic surfactants. Imidazolium surfactants have good interfacial adsorption ability, environment-friendliness, and biocompatibility, they are widely applied in fields of deterging, wetting, medicine, oil and gas development and so on. Moreover, they have been found a good application in drug solubilization, corrosion inhibition, sewage treatment, mesoporous and nano-materials preparation separation. The imidazolium Gemini surfactant is a kind of new surfactant which has prominent advantages, because it owns the properties of both traditional Gemini surfactant and single-chain imidazolium surfactant. So imidazolium Gemini surfactant is increasingly attracted researchers’ interest.Hydrophobically modified water-soluble polymers introduce a small amount of hydrophobic groups in traditional polymer chain (about2-5mol%). Due to the introduction of hydrophobic groups, hydrophobic modified polymer both possess the interfacial activity of conventional surfactant and the bulk phase property of polymer in aqueous solution, and also because of their properties, they have potential in industrial applications such as tack producing, gel preparation, inverse microemulsion preparation, oil recovery, and water treatment. The study on the interaction with surfactants would be very great theory significance and utility value in the cosmetics, pharmaceutical and oil and gas development.In this article, we choose three different types of imidazolium surfactants and hydrophobic modified polyacrylamide with different structures. The aggregation behaviors of the imidazolium amphiphiles on the surface of aqueous solution and in the aqueous solution in the presence of polymer are studied. There are some parts in this thesis: In the first section, an overview was provided about the properties of imidazolium surfactants and hydrophobic modified polyacrylamide; in addition, the application of HMPAM in crude oil emulsion breaking were briefly introduced. The importance of study on imidazolium surfactants with macromolecules and the study progress on the interaction between imidazolium surfactant and macromolecules are summarized.In the second section, the interaction of imidazolium surfactants ([C14-4-C14im]Br2and [C14mim]Br) with hydrophobic modified polyacrylamide (HMPAM) were investigated at low frequency (0.005-0.1Hz) by dilational rheology, and compared the difference between HMPAM and hydrolyzed polyacrylamide (HPAM).The results have showed that the single imidazolium surfactant, polymer and imidazolium surfactant/polymer system, the dilational modulus passes through a maximum value with surfactant concentration or polymer aqueous solutions concentration increasing. The maximum dilational modulus value of mixed system is higher than the one of the pure surfactant which suggests that imidazolium surfactant interact with polymer on the interface, and the interaction enhance the dilational elastic and dilational viscous of interfacial film. In addition, the maximum value of the dilational modulus of [C14-4-C14im]Br2/HMPAM aqueous solution is higher than [C14mim]Br/HMPAM aqueous solution system at low polymer aqueous solution concentration. The interaction between imidazole Gemini surfactant and HMPAM is larger than HP AM at low midazole surfactant concentration.In the thrid section, the π-A isotherms of imidazolium surfactants ([C14-4-C14im]Br2,[C14mim]Br and [C14]2imBr) on subphases of pure water, HMPAM and HP AM polymer aqueous solutions were measured by a Langmuir-Blodgett (LB) film balance, the mono layer formed by imidazolium surfactants at subphases of pure water, HMPAM and HPAM aqoeous solutions transferred onto solid substrates. The LB films were characterized by atomic force microscopy, contact angle and FT-IR measurements. The results show that HMPAM and HPAM polymers are into the interface, and they interact with imidazolium surfactants. The interaction between the two polymers and imidazolium surfactants on the interface were related to imidazolium surfactant and polymer molecular structures. The IR spectra suggests the methylene chain of [C14-4-C14im]Br2is less ordered packing than [C14]2imBr inside the aggregates on the surface of quartz. In the fourth section, the corrosion and inhibitor adsorption processes in carbon steel (A3)/imidazolium surfactants ([C14-4-C14im]Br2and [C14mim]Br)/hydrochloric acid (0.1mol·L-1HC1) systems was studied at15℃by means of electrochemical impedance spectroscopy (EIS), polarization curves, and weight loss measurements.The Quantum chemistry calculation methods have been used to investigate the inhibition mechanism of imidazolium surfactants in carbon steel in theory. At the same time, The influence of the addition of HMPAM on the properties of corrosion inhibition of imidazole Gemini surfactant was studied, which has potential application value in the process of oilfield development. Results show that imidazolium surfactants exhibit a very good performance as inhibitors for carbon steel corrosion in0.1mol·L-1HC1. The inhibition efficiency increases with increasing concentration of imidazolium surfactants. In addition, the inhibition efficiency of [C14-4-C14im]Br2is higher than [C14mim]Br at the same concentration. The weight loss has showed that the adsorption for the studied imidazolium surfactants on carbon steel complies with the Langmuir adsorption isotherm at all studied temperatures. On the bases of thermodynamic adsorption parameters,[C14-4-C14im]Br2is based on chemisorption and [C14mim]Br is based on physisorption for the studied imidazolium surfactants on carbon steel surface. The Quantum chemistry calculation results suggest that the imidazolium surfactants molecules show a high reaction activity, and the whole reaction activity of [C14-4-C14im]Br2is higher than [C14mim]Br, which suggests that [C14-4-C14im]Br2interacts with the surface of carbon steel and the protection of carbon steel surface higher than [C14mim]Br. Besides, the weight loss has showed that the addition of HMPAM could coordinate with imidazolium surfactants to protect carbon steel surface from being corrosion.