Ashraf Arman R, Ryan Justin J, Satkowski Michael M, Lee Byeongdu, Smith Steven D, Spontak Richard J
Corporate Research and Development, The Procter and Gamble Company, Cincinnati, OH, 45224, USA.
Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
Macromol Rapid Commun. 2017 Sep;38(17). doi: 10.1002/marc.201700207. Epub 2017 Jun 29.
Block copolymers have been extensively studied due to their ability to spontaneously self-organize into a wide variety of morphologies that are valuable in energy-, medical-, and conservation-related (nano)technologies. While the phase behavior of bicomponent diblock and triblock copolymers is conventionally governed by temperature and individual block masses, it is demonstrated here that their phase behavior can alternatively be controlled through the use of blocks with random monomer sequencing. Block random copolymers (BRCs), i.e., diblock copolymers wherein one or both blocks are a random copolymer comprised of A and B repeat units, have been synthesized, and their phase behavior, expressed in terms of the order-disorder transition (ODT), has been investigated. The results establish that, depending on the block composition contrast and molecular weight, BRCs can microphase-separate. We also report that large variation in incompatibility can be generated at relatively constant molecular weight and temperature with these new soft materials. This sequence-controlled synthetic strategy is extended to thermoplastic elastomeric triblock copolymers differing in chemistry and possessing a random-copolymer midblock.
由于嵌段共聚物能够自发地自组装成各种形态，这些形态在能源、医学和保护相关（纳米）技术中具有重要价值，因此受到了广泛研究。虽然双组分二嵌段和三嵌段共聚物的相行为传统上由温度和各嵌段质量控制，但本文证明，它们的相行为也可以通过使用具有随机单体序列的嵌段来控制。已经合成了嵌段无规共聚物（BRC），即其中一个或两个嵌段为包含A和B重复单元的无规共聚物的二嵌段共聚物，并研究了其以有序-无序转变（ODT）表示的相行为。结果表明，根据嵌段组成对比度和分子量，BRC可以发生微相分离。我们还报告称，使用这些新型软材料，在相对恒定的分子量和温度下，可以产生不相容性的巨大变化。这种序列控制的合成策略扩展到了化学性质不同且具有无规共聚物中间嵌段的热塑性弹性体三嵌段共聚物。
