A polymer—microemulsion interaction: The coacervation model
A polymer—microemulsion interaction: The coacervation model
复制标题
聚合物-微乳液相互作用：凝聚模型
DOI：
10.1016/0021-9797(82)90304-6
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发表时间：
1982
影响因子：
8.6
通讯作者：
J. Bock
中科院分区：
文献类型：
--
作者：
D. Siano;J. Bock
成功预测相分离的许多定性特征的模型可以基于这样的假设，即当用外相稀释或当与聚合物（其不与表面活性剂络合）混合时，微乳液颗粒保持其完整性。在这种情况下，微乳液颗粒以类似于大分子的方式表现出类似的行为，因此可以预测聚合物-微乳液相图将具有与聚合物-聚合物2-溶剂情况所表现出的定性相似性。大多数实验是通过测量聚合物微乳液混合物的浊点来进行的。混合物的浊点被发现是（通常）添加的聚合物的重量分数的线性函数，并随着分子量的增加而降低。这些曲线的斜率的对数相对于聚合物分子量的对数的图是线性的，斜率指定为β。研究的25个系统的β值落在0.55 ± 0.15的狭窄范围内。在特性粘度和聚合物分子量之间的关系中，这些值被认为与Mark-Houwink指数相同。这种对应关系的原因似乎是凝聚发生在约等于阈值重叠浓度的聚合物浓度。三元相图与微乳液颗粒，盐水，和聚合物选择作为假组分也表现出许多功能预测的模型。相边界的不对称性是在预期的方向和渐近线与预期的微乳液和聚合物分子量的独立性也被证明。与模型一致的是，控制变量是聚合物的重均分子量，而不是数均分子量。
A model which successfully predicts many of the qualitative features of the phase separation can be based upon the assumption that the microemulsion particle retains its integrity when diluted with external phase or when mixed with a polymer (which does not complex with the surfactants). In this case, the microemulsion particle behaves thermodynamically in a manner similar to a macromolecule so that one can predict that the polymer—microemulsion phase diagram will have qualitative similarities to that exhibited by the polymer—polymer2-solvent case. Most of the experiments were conducted by following the phase boundaries by measurements of the cloud points of the polymermicroemulsion mixtures. The cloud points of the mixtures were found to be (usually) linear functions of the weight fraction of the added polymer and decreased with increasing molecular weight. Plots of the logarithm of the slopes of these curves against the logarithm of the polymer molecular weight were linear, with a slope designated as β. The values for β for twenty-five systems studied fell within the narrow range of 0.55 ± 0.15. These values were seen to be the same as the Mark—Houwink exponents in the relationship between the intrinsic viscosity and the polymer molecular weight. The reason for this correspondence appears to be that the coacervation occurs at a polymer concentration about equal to the threshold overlap concentration. Ternary phase diagrams with microemulsion particles, brine, and polymer selected as pseudocomponents also exhibit many of the features predicted by the model. The phase boundary asymmetry is in the direction expected and asymptotes with the expected independence upon microemulsion and polymer molecular weights are also demonstrated. In agreement with the model, it is shown that the controlling variable is polymer weight average, rather thanzor number average molecular weight.