Departamento de Química, Universidade Federal de Santa Catarina, UFSC, Florianópolis, SC 88040-900, Brazil.
J Colloid Interface Sci. 2012 Mar 15;370(1):94-101. doi: 10.1016/j.jcis.2011.12.049. Epub 2011 Dec 28.
Four modified hyperbranched polyethylene imines (PEIs) were synthesized by means of the alkylation of PEI. SAXS, viscosity, surface tension, and pyrene fluorescence emission were then used as techniques to examine the conformation and aggregation of the modified PEIs in aqueous solution, in the absence and presence of sodium dodecylsulfate (SDS). Analysis of the SAXS data showed that the radius of gyration decreases with an increase in the alkyl chain length of the polymer, while the viscosity data indicated a decrease in the intrinsic viscosity under the same conditions. The nonmodified PEI was not surface active, while the hydrophobically modified samples showed pronounced surface activity and the presence of hydrophobic domains. On addition of SDS, the onset of the formation of polymer-surfactant complexes was determined, indicating a decrease in the critical aggregate concentration with an increase in the alkyl chain length of the polymer backbone.
四种改性超支化聚乙烯亚胺（PEI）通过 PEI 的烷基化反应合成。然后使用小角 X 射线散射（SAXS）、粘度、表面张力和芘荧光发射技术来研究改性 PEI 在水溶液中的构象和聚集，以及在存在和不存在十二烷基硫酸钠（SDS）的情况下。SAXS 数据分析表明，回转半径随着聚合物烷基链长度的增加而减小，而在相同条件下，特性粘度减小。非改性的 PEI 没有表面活性，而疏水性改性的样品表现出明显的表面活性和存在疏水域。加入 SDS 后，确定了聚合物-表面活性剂复合物形成的开始，表明临界聚集浓度随聚合物主链烷基链长度的增加而降低。
