The simultaneous use of nonequilibrium reaction processing and complex macromolecular architecture is an exciting way to achieve nanostructures that are not easily accessible via standard static block polymer self-assembly. Previous work has shown that the polymerization of styrene in the presence of a poly(styrene)-block-poly(butadiene) (PS-PBD) diblock copolymer induces a nanostructural transition from a lamellar (LAM) to a hexagonally packed cylinder (HEX) morphology. The transition was found to be driven by in situ PS grafting from the PBD block, which transforms the PS-PBD coil–coil diblock copolymer to a poly(styrene)-block-[poly(butadiene)-graft-poly(styrene)] (PS-b-PBD-g-PS) coil–comb block polymer. In situ small-angle X-ray scattering and oscillatory shear dynamic mechanical spectroscopy measurements show that the order–order transition is not a simple epitaxial transition seen in prototypical block polymers, but undergoes a complex phase path in which the starting LAM phase at room temperature before polymerization initially disorders at elevated temperatures, evolves from a disordered phase to what is presumed to be a hexagonally perforated lamellae phase during the polymerization, and then transitions to a HEX phase on cooling to room temperature. The high-temperature phase persists for extended periods of time during the polymerization process, which allows for both the trapping and the characterization of the structure at room temperature. By utilizing nonequilibrium reactive processing to convert linear block copolymers to comb–coil type polymers, the creation of polymers with complex molecular topologies can be synthetically simplified while simultaneously allowing for the development of new processing modalities.

中文翻译：

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在嵌段共聚物/单体共混物的聚合诱导的纳米结构转变过程中破译复杂的相行为

同时使用非平衡反应过程和复杂的高分子结构是获得纳米结构的令人兴奋的方式，而纳米结构无法通过标准的静态嵌段聚合物自组装轻易获得。以前的工作已经表明，苯乙烯在聚（苯乙烯）的存在下聚合-嵌段-聚（丁二烯）（PS-PBD）二嵌段共聚物诱导纳米结构从层状（LAM）过渡到六边形填充气缸（HEX）形态学。发现过渡是由PBD嵌段的原位PS接枝驱动的，该过程将PS-PBD线圈-线圈二嵌段共聚物转变为聚（苯乙烯）-嵌段-[聚（丁二烯）-接枝-聚（苯乙烯）] （PS- b -PBD- g-PS）线圈–梳状嵌段聚合物。原位小角X射线散射和振荡剪切动态力学光谱测量表明，阶跃转变不是典型的嵌段聚合物中看到的简单外延转变，而是经历了复杂的相路径，其中室温下起始LAM相在聚合反应最初在高温下发生紊乱之前，它在聚合过程中从无序相演变为推测为六边形穿孔的薄片相，然后在冷却至室温时转变为HEX相。高温相在聚合过程中会持续较长的时间，从而可以在室温下捕获和表征结构。