Study On The Interaction Between Cationic Surfactants And Silica Nanoparticles And Their Applications

Surfactants have a wide range of applications owing to their special properties of wetting,emulsification and foaming attributed to their amphiphilic structure.With the development of technology,the use of surfactants has been extended to the field of nanomaterials.Studies on interactions between surfactants and nanoparticles are of great importance in both theoretical and practical aspects.In this work,the interactions between cationic surfactants and silica nanoparticles were investigated,and the main contents of this paper are summarized as following:In chapter 1,the properties and applications of silica nanoparticles as well as the properties of surfactants were reviewed.The research advances on the interactions between surfactants and nanoparticles in recent years were also summarized,followed by the research ideas and framework of the present study.In chapter 2,the interactions between alkyltrimethylammonium chloride and silica nanoparticles?referred to as CQ380?were investigated.The factors influencing viscosity,such as pH,concentration and hydrophobic chain of surfactants as well as salts were examined.The adsorption capacities of different surfactants on silica were compared through measuring the surface tension of the solutions composed of silica and different surfactants.Moreover,rheological properties of colloidal gels formed between silica nanoparticles and cationic surfactant were evaluated.The interaction mechanism between cationic surfactant and silica nanoparticles was discussed using a combination of viscosity,particle size distribution,changes in surface tension and microstructure.In chapter 3,the gel composed of octadecyl trimethyl ammonium chloride?referred to Ci8TAC?,sodium salicylate?referred to NaSal?and silica nanoparticles was studied by rheological measurement.The optimal composition of C18TAC,NaSal and nano-SiO₂ was confirmed according to the results of rheological measurement.The zero shear viscosity,viscosity under high shear rate and viscoelasticity of C18TAC-NaSal-SiO₂ were investigated.Finally,the properties of Ci8TAC-NaSal-SiO₂ such as sand carring,fluid loss as well as core damage were evaluated.In chapter 4,the resonance light scattering?RLS?spectrum between cationic surfactant and silica nanoparticles was investigated.The experimental conditions,such as concentration of NaOH,reaction time and temperature,were examined.The enhanced resonance light scattering intensity was proportional to the concentration of cationic surfactant in a certain range.Based on these,a novel simple method has been proposed to determine the contents of cationic surfactant.