Vleugels Leo F W, Pollet Jennifer, Tuinier Remco
†DSM Chemical Technology BV, Advanced Chemical Engineering Solutions (ACES), P.O. Box 18, 6160 MD Geleen, The Netherlands.
‡Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
J Phys Chem B. 2015 May 21;119(20):6338-47. doi: 10.1021/acs.jpcb.5b02043. Epub 2015 May 12.
Polyelectrolyte-surfactant complexes (PESC) are a class of materials which form spontaneously by self-assembly driven by electrostatic and hydrophobic interactions. PESC containing sodium lauryl ether sulfates (SLES) have found wide application in hair care products like shampoo. Typically, SLES with only one or two ethylene oxide (EO) groups are used for this application. We have studied the influence of the size of the EO block (ranging from 0 to 30 EO groups) on complexation with two model polycations: linear polyDADMAC and branched PEI. PESC size and electrostatic properties were determined during stepwise titration of buffered polycation solutions. The critical aggregation concentration (CAC) of PESC was determined by surface tension measurements and fluorescence spectroscopy. For polyDADMAC, there is no influence of the size of the EO block on the complexation behavior; the stiff polycation governs the structure formation. For PEI, it was seen that the EO block size does affect the structure of the complexes. The CAC value of the investigated complexes turns out to be rather independent of the EO block size; however, the CMC/CAC ratio decreases with increasing size of the EO block. This latter observation explains why the Lochhead-Goddard effect is most effective for small EO blocks.
聚电解质 - 表面活性剂复合物（PESC）是一类通过静电和疏水相互作用驱动自组装而自发形成的材料。含有月桂醇聚醚硫酸酯钠（SLES）的PESC已在洗发水等护发产品中得到广泛应用。通常，仅含有一个或两个环氧乙烷（EO）基团的SLES用于此应用。我们研究了EO嵌段大小（范围从0到30个EO基团）对与两种模型聚阳离子（线性聚二烯丙基二甲基氯化铵和支化聚乙烯亚胺）络合的影响。在缓冲聚阳离子溶液的逐步滴定过程中测定了PESC的大小和静电性质。通过表面张力测量和荧光光谱法测定了PESC的临界聚集浓度（CAC）。对于聚二烯丙基二甲基氯化铵，EO嵌段大小对络合行为没有影响；刚性聚阳离子控制结构形成。对于聚乙烯亚胺，可以看出EO嵌段大小确实会影响复合物的结构。所研究复合物的CAC值结果与EO嵌段大小相当无关；然而，临界胶束浓度（CMC）/ CAC比值随着EO嵌段大小的增加而降低。后一观察结果解释了为什么洛赫黑德 - 戈达德效应对于小EO嵌段最为有效。
