Causse J, Lagerge S, de Menorval L C, Faure S
Laboratoire des Agrégats Moléculaires et Matériaux Inorganiques, C.N.R.S. UMR-5072, Université de Montpellier II, CC 015, Place E. Bataillon, 34095 Montpellier Cedex 05, France.
J Colloid Interface Sci. 2006 Aug 15;300(2):713-23. doi: 10.1016/j.jcis.2006.04.042. Epub 2006 Apr 25.
Solubilization of tributylphosphate (TBP), a polar oil, in various micellar solutions of Pluronic has been investigated by turbidimetry emphasizing the effect of temperature and the role of the PPO and PEO blocks on the phase behavior of the three components systems (Pluronic-TBP-water). [Temperature-composition] diagrams allow monophasic and diphasic domains to be delimited. Two temperatures are shown to have a determining effect on the phase behavior (TBP solubilization); the well known cloud point temperature (CPT, here defined for the three components system) and the solubilization minimum temperature (SMT) which is defined as the lowest temperature allowing solubilization of TBP in the system. Both temperature depend on the copolymer structure and, interestingly, are directly related to the TBP concentration in the medium. Monophasic microemulsions are observed when the temperature ranges between the SMT and the CPT. When T<SMT, the phase separation occurs and is related to the formation of TBP in water emulsion droplets. When T>CPT the system separates in two phase due to the co-precipitation of TBP and Pluronic. Moreover an unexpected evolution of the CPT with the TBP content clearly indicates the occurrence of a structural change of the microemulsions which allows higher quantities of TBP to be solubilized. But the structural change does not allow alone higher quantities of TBP to be solubilized. A well compromise between the SMT and the CPT must be also observed so as to obtain a large extent of monophasic domain after the restructuration. The best compromise is obtained with Pluronics with intermediate hydrophobic character. Reversely, hydrophobic and hydrophilic Pluronics exhibit a very small extent of monophasic domain after the restructuration which does not allow benefit by the structural change.
通过比浊法研究了极性油磷酸三丁酯（TBP）在多种普朗尼克胶束溶液中的增溶作用，重点考察了温度的影响以及聚丙二醇（PPO）和聚环氧乙烷（PEO）嵌段对三元体系（普朗尼克-TBP-水）相行为的作用。[温度-组成]图可界定单相和双相区域。结果表明，有两个温度对相行为（TBP增溶）具有决定性影响；一个是众所周知的浊点温度（CPT，此处定义为三元体系的浊点温度），另一个是增溶最低温度（SMT），它被定义为使TBP在体系中能够增溶的最低温度。这两个温度均取决于共聚物结构，有趣的是，它们与介质中TBP的浓度直接相关。当温度介于SMT和CPT之间时，可观察到单相微乳液。当T < SMT时，会发生相分离，这与水乳液滴中TBP的形成有关。当T > CPT时，由于TBP和普朗尼克的共沉淀，体系会分离为两相。此外，CPT随TBP含量的意外变化清楚地表明微乳液发生了结构变化，从而能够增溶更多量的TBP。但仅靠结构变化并不能增溶更多量的TBP。还必须在SMT和CPT之间达成良好的平衡，以便在重组后获得较大范围的单相区域。具有中等疏水特性的普朗尼克能够实现最佳平衡。相反，疏水型和亲水型普朗尼克在重组后单相区域的范围非常小，无法从结构变化中受益。
