Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India.
J Colloid Interface Sci. 2010 May 15;345(2):346-50. doi: 10.1016/j.jcis.2010.01.079. Epub 2010 Feb 1.
The cloud points (CP) of 1 g/dl solutions of polyethylene oxide-polypropylene oxide (PEO-PPO) based triblock copolymers (Pluronics® P84, L64, L44 and Reverse Pluronics® 10R5, 25R4, 17R4) were measured as a function of their molecular weight and added ionic surfactant. For identical PEO/PPO ratios, copolymers with lower molecular weight show a larger increase in the cloud point in the presence of surfactants than polymers with higher molecular weight. The opposite trend has been observed for reverse Pluronics. The cloud points of polymers with different PEO/PPO ratios have also been reported. An increase in the size of the middle PEO block in reverse Pluronics has a more significant effect on cloud points than molecular weight increment. Ionic surfactants produced marked increases in the cloud points of copolymer solutions. The effect was much larger for surfactants with higher hydrophobicity. Cationic surfactants with different chain lengths were used to examine the surfactant-polymer interaction. A novel approach for normalising the cloud points to their relative values has been carried out to see the clear effect of ionic surfactants. Tri component systems, comprising polymers, cetyltrimethylammonium bromide (C(16)TABr) surfactant and salt (NaBr), have also been studied to see the effect of salt on the phase separation behaviour of solutions within the framework of our new cloud point approach.
1g/dl 浓度的聚氧化乙烯-聚氧化丙烯（PEO-PPO）嵌段共聚物（Pluronics® P84、L64、L44 和 Reverse Pluronics® 10R5、25R4、17R4）溶液的浊点（CP）随其分子量和添加的离子型表面活性剂而变化。对于相同的 PEO/PPO 比例，分子量较低的共聚物在存在表面活性剂时浊点的增加幅度大于分子量较高的聚合物。相反的趋势也在 Reverse Pluronics 中观察到。还报道了具有不同 PEO/PPO 比例的聚合物的浊点。Reverse Pluronics 中中间 PEO 嵌段尺寸的增加对浊点的影响比对分子量增加的影响更大。离子型表面活性剂显著增加共聚物溶液的浊点。疏水性较高的表面活性剂的效果更大。使用不同链长的阳离子表面活性剂来研究表面活性剂-聚合物相互作用。采用一种新的方法将浊点归一化为相对值，以清楚地观察离子型表面活性剂的影响。还研究了由聚合物、十六烷基三甲基溴化铵（C（16）TABr）表面活性剂和盐（NaBr）组成的三元体系，以在我们新的浊点方法的框架内研究盐对溶液相分离行为的影响。
