Synthesis And Aggregation Behavior Of Cationic-Nonionic Surfactants

This article has three parts,synthesized the function surfactants of N-alkyl-N,N-dimethyl-N-?2,3-epoxy propyl?ammonium chloride,studied the surface activity and aggregation behavior with traditional surfactants.In the chapter I,it mainly discusses the types and properties of traditional surfactants,including the adsorption properties of surfactants at the two-phase interface,the properties and applications of functional surfactant-epoxy and quaternary ammonium surfactants,and cationic surface activity;interaction of agents with traditional anions,two-phase ionic and non-ionic surfactants.In the chapter II of part one,a series of N-alkyl-N,N-dimethyl-N-?2,3-epoxy propyl?ammonium chloride?CnEAC?with alkyl of decyl,dodecyl,tetradecyl,hexadecyl,octadecyl and octadecyl were synthesized.The surface properties and aggregation behaviors were studied by surface tension,conductivity,dynamic light scattering,steady state fluorescence,fluorescence quenching,and oscillating bubble methods.Data of critical micelle concentration?cmc?,surface tension at cmc showed that the surface activity increased with the increase of hydrocarbon chain length.The micellization was entropy-driven process when the temperature higher than 25oC,and when the temperature lower than 25oC,the micellization was enthalpy-driven process.In the chapter II of part two,we studied the viscoelasticity and dynamic adsorption process of surfactants CnEAC?n=10,12,14,16?at air/water interface under different temperatures,concentrations and frequencies,as well as the influence of salt?NaCl and Na2CO3?environment on the rheological behavior at surfactant interface.The experimental principle was based on the molecular thermodynamics and kinetics of the interfacial layer,change the morphology of small droplets by shaking,and quantitatively analyze the changes of the interface structure in the secondary process.The results shown that with increased the oscillating frequency and temperature,the molecules cannot be exchanged between the interface and bulk phase in time,resulting in an increase in the composite modulus.As the concentration of CnEAC increases,adsorption and desorption appear at the interface.In the chapter III of part one,we studied the interactions between N-tetradecyl-N,N-dimethyl-N-?2,3-epoxy propyl?ammonium chloride?C14EAC?and commonly surfactants including sodium dodecyl?SDS?sodium dodecyl sulfonate?AS?,dodecyltrimethylammonium chloride?DTAC?and N,N-dimethyldodecylamine oxide?C12DMAO?by surface tension,conductivity,steady-state fluorescence and dynamic scattering and Rubingh regular solution methods,respectively.The values of cmc,surface tension at cmc,pc₂₀,?_cmc,?_max,and A_min were calculated,which indicate a strong synergistic effect between C14EAC and SDS?and AS?,compared with the relative weak interaction between DTAC?C12DMAO?and C14EAC.The interaction between C14EAC and SDS?AS?is temperature dependent,results the cmc of the mixed surfactant systems variation with temperature.Thermal parameters calculated from conductivity show that the micellization of C14EAC/SDS?AS?mixed systems is spontaneous and exothermic process.The results obtained from steady-state fluorescence,dynamic scattering and rubingh regular solution confirmed the strong interaction between surfactants.In the chapter III of part two,the aggregon behavior of salt-free catanionic surfactants,tetradecyltrimethyl ammonium hydroxide?TTAOH?/fatty acid?FA?including octanoic acid?OA?,decylic acid?DA?and lauric acid?LA?in aqueous solutions were studied.The critical micelle concentration?cmc?,surface tension at cmc(?_cmc),surface excess(?_max),mean molecular surface area(A_min),adsorption efficiency(pc₂₀)and surface tension reduction effectiveness(?_cmc)were obtained from surface tension isotherms.The influence of temperature on the surface tension of salt-free TTAOH/FA?TTAOF?systems was investigated.Data of adsorption dynamics indicated that at fixed adsorption time,the order of adsorption capacity was TTAOH<TTAOH/OA?TTAOO?<TTAOH/DA?TTAOD?<TTAOH/LA?TTAOL?.The adsorption process of salt-free TTAOF was adsorption-controlled.The complex and storage moduli increased with increasing oscillation frequency,however,the loss modulus showed the opposite trend.The complex modulus passed through a maximum value with increasing concentration of salt-free surfactant TTAOF.The adsorbed TTAOF layer was elastic,and the elasticity increased with increasing hydrocarbon chain length of FA.