From Micelles to Randomly Connected, Bilayered Membranes in Dilute Block Copolymer Blends
From Micelles to Randomly Connected, Bilayered Membranes in Dilute Block Copolymer Blends
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稀嵌段共聚物共混物中从胶束到随机连接的双层膜
作者：
J. H. Laurer;J. Fung;J. Sedat;Steven D Smith;J. Samseth;K. Mortensen;D. Agard;R. Spontak
作为大分子表面活性剂，二嵌段共聚物在母体均聚物的存在下有序地形成各种形态。在这里，我们探讨了化学不相容性和界面刚性对共聚物/均聚物在一定共混成分下形态的影响。为此目的合成了五种共聚物，每种共聚物具有随机序列的中间段，其分子量从0到40 wt %不等。虽然共聚物胶束是稀（均聚富）共混物的代表，但随着中嵌段分数的增加，会产生复杂的双层形态，包括囊泡和异常各向同性的“海绵”相。小角度中子散射提供了特征微观结构尺寸的定量评估，而透射电子显微断层扫描产生了由海绵相组成的随机连接的双层膜的第一个三维图像。31参。， 3个无花果。
As macromolecular surfactants, diblock copolymers order into a variety of morphologies in the presence of a parent homopolymer. Here, we probe the effects of chemical incompatibility and interfacial rigidity on the morphology of copolymer/homopolymer blends at constant blend composition. Five copolymers, each possessing a random-sequence midblock that is varied from 0 to 40 wt % of the copolymer molecular weight, have been synthesized for this purpose. While copolymer micelles are representative of dilute (homopolymer-rich) blends, complex bilayered morphologies, including vesicles and the anomalous isotropic `sponge` phase, are produced upon increasing the midblock fraction. Small-angle neutron scattering provides a quantitative assessment of characteristic microstructural dimensions, while transmission electron microtomography yields the first three-dimensional images of the randomly connected, bilayered membrane comprising the sponge phase. 31 refs., 3 figs.