Noskov B A, Grigoriev D O, Lin S-Y, Loglio G, Miller R
St. Petersburg State University, Chemical Faculty, Universitetsky pr. 2, 198904 St. Petersburg, Russia.
Langmuir. 2007 Sep 11;23(19):9641-51. doi: 10.1021/la700631t. Epub 2007 Aug 14.
The dynamic surface elasticity, dynamic surface tension, and ellipsometric angles of mixed aqueous poly(diallyldimethylammonium chloride)/sodium dodecylsulfate solutions (PDAC/SDS) have been measured as a function of time and surfactant concentration. This system represents a typical example of polyelectrolyte/surfactant complex formation and subsequent aggregation on the nanoscale. The oscillating barrier and oscillating drop methods sometimes led to different results. The surface viscoelasticity of mixed PDAC/SDS solutions are very close to those of mixed solutions of sodium polystyrenesulfonate and dodecyltrimethylammonium bromide but different from the results for some other polyelectrolyte/surfactant mixtures. The abrupt drop in surface elasticity when the surfactant molar concentration approaches the concentration of charged polyelectrolyte monomers is caused by the formation of microparticles in the adsorption layer. Aggregate formation in the solution bulk does not influence the surface properties significantly, except for a narrow concentration range where the aggregates form macroscopic flocks. The mechanism of the observed relaxation process is controlled by the mass exchange between the surface layer and the flocks attached to the liquid surface.
已测量了混合的聚二烯丙基二甲基氯化铵/十二烷基硫酸钠水溶液（PDAC/SDS）的动态表面弹性、动态表面张力和椭偏角，它们是时间和表面活性剂浓度的函数。该体系是聚电解质/表面活性剂复合物形成及随后在纳米尺度上聚集的典型例子。振荡屏障法和振荡液滴法有时会得出不同的结果。混合PDAC/SDS溶液的表面粘弹性与聚苯乙烯磺酸钠和十二烷基三甲基溴化铵混合溶液的非常接近，但与其他一些聚电解质/表面活性剂混合物的结果不同。当表面活性剂摩尔浓度接近带电聚电解质单体浓度时表面弹性的突然下降是由吸附层中微粒的形成引起的。溶液本体中的聚集体形成对表面性质没有显著影响，除了在一个狭窄的浓度范围内聚集体形成宏观絮状物。观察到的弛豫过程的机制由表面层与附着在液体表面的絮状物之间的质量交换控制。
