Dai Sheng, Tam Kam Chiu
Singapore-MIT Alliance and School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Republic of Singapore.
J Phys Chem B. 2006 Oct 26;110(42):20794-800. doi: 10.1021/jp061438+.
The micellization of sodium dodecyl sulfate (SDS) in different glycol-water solvent mixtures was studied using the isothermal titration calorimetric (ITC) technique. At the same time, microcalorimetric titrations were also carried out to monitor the binding interaction of SDS and poly(ethylene oxide) (PEO) in the presence of different cosolvents. The demicellization of SDS in mixtures of water and cosolvents is different from that in water due to the reduction in solvent polarity and charge interaction of surfactants. The critical micelle concentration (cmc) first decreases with the addition of a small amount of cosolvents and then increases at higher cosolvent concentrations. The thermodynamics of surfactant micellization can be analyzed using the solubility parameters of solvent mixtures. For the binding interaction between SDS and PEO in different solvent mixtures, the dehydration process at low SDS concentrations is replaced by the chain solubilization process with decreasing solvent polarity. With further reduction in the solvent polarity, the binding interaction between SDS and PEO becomes weak and no aggregates can be formed beyond a certain glycol concentration. The binding interaction between SDS and PEO in different solvent mixtures was analyzed and ascribed to the effects of PEO solubility and hydrophobicity of SDS.
采用等温滴定量热法（ITC）研究了十二烷基硫酸钠（SDS）在不同乙二醇 - 水混合溶剂中的胶束化作用。同时，还进行了微量热滴定，以监测在不同助溶剂存在下SDS与聚环氧乙烷（PEO）的结合相互作用。由于溶剂极性降低和表面活性剂的电荷相互作用，SDS在水和助溶剂混合物中的去胶束化作用与在水中不同。临界胶束浓度（cmc）首先随着少量助溶剂的加入而降低，然后在较高助溶剂浓度下升高。表面活性剂胶束化的热力学可以用溶剂混合物的溶解度参数进行分析。对于不同溶剂混合物中SDS与PEO之间的结合相互作用，在低SDS浓度下的脱水过程随着溶剂极性降低被链增溶过程所取代。随着溶剂极性进一步降低，SDS与PEO之间的结合相互作用变弱，超过一定乙二醇浓度就无法形成聚集体。分析了不同溶剂混合物中SDS与PEO之间的结合相互作用，并将其归因于PEO溶解度和SDS疏水性的影响。
