Effect of Nonadsorbing Polyelectrolytes on Colloidal Interactions in Aqueous Mixtures
Effect of Nonadsorbing Polyelectrolytes on Colloidal Interactions in Aqueous Mixtures
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DOI：
10.1006/jcis.1997.4940
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发表时间：
1997-07
影响因子：
9.9
通讯作者：
Sharma;Tan;Walz
中科院分区：
文献类型：
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作者：
Sharma;Tan;Walz
使用全内反射显微镜光学技术测量了添加非吸附性带电聚合物聚苯乙烯磺酸钠 (SPSS) 对 15 m 直径聚苯乙烯颗粒和玻璃板之间相互作用能量分布的影响。典型的剖面由大间距处的排斥屏障和随后的次级井组成。在聚合物分子呈棒状的无盐溶液中也观察到了远程三级井的证据。添加电解质会导致第三井深度减小，并在大间距处产生振荡。此外，使用光学光散射测量了 SPSS 存在下带电聚苯乙烯颗粒溶液的稳定性。由于颗粒之间的静电排斥，该溶液在不添加聚合物的情况下对于初级絮凝是稳定的。然而，由于长程吸引力耗尽力，在低 SPSS 浓度（0.2 wt%）下，可逆二次絮凝发生局部势能最小值。聚合物在临界絮凝浓度 (v *) 下引起絮凝，发现该浓度随着粒径的增加而降低。没有观察到胶乳分散体的重新稳定。
The effect of adding a nonadsorbing charged polymer, sodium polystyrene sulfonate (SPSS), on the interaction energy profile between a 15 m diameter polystyrene particle and a glass plate was measured using the optical technique of total internal reflection microscopy. A typical profile consisted of a repulsive barrier at large separations followed by a secondary well. Evidence of a longer-range tertiary well was also observed in salt-free solutions where the polymer molecules are rod-like. Addition of electrolyte causes a reduction in the depth of the tertiary well and produces oscillations at large separations. In addition, the stability of a solution of charged polystyrene particles in the presence of SPSS was measured using optical light scattering. Because of the electrostatic repulsion between the particles, the solution was stable against primary flocculation with no added polymer. However, because of long range attractive depletion forces, reversible secondary flocculation occurred into a local potential energy minimum at low SPSS concentrations (order 0.2 wt%). The polymer caused flocculation at a critical flocculation concentration (v *) which was found to decrease with increasing particle size. No restabilization of the latex dispersions was observed.