论文部分内容阅读
以羧甲基纤维素钠(Na CMC)-烷基三甲基溴化铵(CnTAB)复合体系为研究对象,在Na CMC亚浓缠结溶液中考察了CnTAB烷基尾链长度对CnTAB临界缔合浓度(cac)及溶液流变行为的影响.采用荧光探针法测得cac值,根据吉布斯自由能定量分析了烷基尾链对胶束缔合行为的影响.稳态流变测试结果表明,较高浓度CnTAB对Na CMC亚浓缠结溶液有强烈的增黏作用.显微观察表明,低浓度CnTAB形成孤立胶束(约5nm),而较高浓度CnTAB则形成胶束复合聚集体(约30 nm).扣除胶束电荷中和所致降黏作用后,孤立胶束表现为等效刚性球,Na CMC亚浓缠结溶液的黏度变化符合Einstein方程;相反,胶束在临界浓度以上发生逾渗,形成胶束复合聚集体,进一步形成贯穿于Na CMC分子缠结网路的胶束逾渗网络.首次揭示了复合体系增黏的实质是胶束网络逾渗,而不是由胶束吸附聚电解质链形成物理网络.增黏阶段Na CMC亚浓缠结溶液的黏度变化符合逾渗模型和平均场理论.长程静电相互作用控制胶束缔合与逾渗行为,逾渗临界胶束体积分数随CnTAB尾链长度增加而降低,临界胶束表面间距随CnTAB尾链长度增加而增大.
Taking sodium carboxymethyl cellulose (Na CMC) -alkyltrimethylammonium bromide (CnTAB) composite system as the research object, the effects of the CnTAB alkyl tail length on the CnTAB criticality (Cac) and the rheological behavior of the solution.The cac value was measured by the fluorescent probe method, and the influence of alkyl tail-chain on the association behavior of micelles was quantitatively analyzed based on the Gibbs free energy. The results showed that the higher concentration of CnTAB had a strong effect on the concentration of Na CMC sub-entangled solution. Microscopic observation showed that the low concentration of CnTAB formed isolated micelles (about 5nm), while the higher concentration of CnTAB formed micelle complex aggregation (About 30 nm) .After subtracting the effect of viscosity reduction caused by neutralization of micellar charge, the isolated micelles behave as an equivalent rigid sphere. The viscosity change of Na CMC sub-entangled solution accords with the Einstein equation. On the contrary, Percolation occurred above the concentration, the formation of micellar complex aggregates, and further formed through the Na CMC molecular entanglement network micellar percolation network for the first time revealed that the synergistic composite system is essentially the percolation of the micellar network, rather than by Micellar adsorption of polyelectrolyte chains to form a physical network The viscosity changes are in accordance with the percolation model and the mean field theory. The long-range electrostatic interaction controls the association and percolation behavior of the micelles, the percolation critical micelle volume fraction decreases as the length of the CnTAB tail chain increases, and the critical micelle spacing varies with the CnTAB tail chain The length increases and increases.