Bai Guangyue, Nichifor Marieta, Lopes António, Bastos Margarida
CIQ (UP), Department of Chemistry, Faculty of Sciences, University of Porto, R. Campo Alegre, 687, P-4169-007 Porto, Portugal.
J Phys Chem B. 2005 Jan 13;109(1):518-25. doi: 10.1021/jp046552b.
We have used a precision isothermal titration microcalorimeter (ITC) to measure the enthalpy curves for the interaction of a hydrophobically modified polyelectrolyte (D40OCT30) with oppositely charged surfactants (SC(n)S) in aqueous solution. D40OCT30 is a newly synthesized polymer based on dextran having pendant N-(2-hydroxypropyl)-N,N-dimethyl-N-octylammonium chloride groups randomly distributed along the polymer backbone with degree of substitution of 28.1%. The employed anionic surfactants are sodium octyl sulfate (SC(8)S) and sodium tetradecyl sulfate (SC(14)S). Microcalorimetric results along with turbidity and kinematic viscosity measurements demonstrate systematically the thermodynamic characterization of the interaction of D40OCT30/SC(n)S. A three-dimensional diagram with the derived phase boundaries is drawn to describe the effect of the alkyl chain length of surfactant and of the ratio between surfactant and pendant groups on the interaction. A more complete picture of the interaction mechanism for D40OCT30/SC(n)S systems is proposed here.
我们使用了一台精密等温滴定量热仪（ITC）来测量疏水改性聚电解质（D40OCT30）与水溶液中带相反电荷的表面活性剂（SC(n)S）相互作用的焓变曲线。D40OCT30是一种基于葡聚糖新合成的聚合物，其侧链N-(2-羟丙基)-N,N-二甲基-N-辛基氯化铵基团沿聚合物主链随机分布，取代度为28.1%。所使用的阴离子表面活性剂为辛基硫酸钠（SC(8)S）和十四烷基硫酸钠（SC(14)S）。微量量热结果以及浊度和运动粘度测量系统地展示了D40OCT30/SC(n)S相互作用的热力学特征。绘制了带有推导相界的三维图，以描述表面活性剂烷基链长度以及表面活性剂与侧链基团比例对相互作用的影响。本文提出了D40OCT30/SC(n)S体系相互作用机制的更完整图景。
