Guerin Gerald, Rupar Paul A, Winnik Mitchell A
Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada.
Polymers (Basel). 2021 Sep 16;13(18):3122. doi: 10.3390/polym13183122.
Studying the growth of 1D structures formed by the self-assembly of crystalline-coil block copolymers in solution at elevated temperatures is a challenging task. Like most 1D fibril structures, they fragment and dissolve when the solution is heated, creating a mixture of surviving crystallites and free polymer chains. However, unlike protein fibrils, no new nuclei are formed upon cooling and only the surviving crystallites regrow. Here, we report how trapping these crystallites at elevated temperatures allowed us to study their growth kinetics at different annealing times and for different amounts of unimer added. We developed a model describing the growth kinetics of these crystallites that accounts for fragmentation accompanying the 1D growth process. We show that the growth kinetics follow a stretched exponential law that may be due to polymer fractionation. In addition, by evaluating the micelle growth rate as a function of the concentration of unimer present in solution, we could conclude that the micelle growth occurred in the mononucleation regime.
研究结晶-线圈嵌段共聚物在溶液中于高温下自组装形成的一维结构的生长是一项具有挑战性的任务。与大多数一维纤维结构一样，当溶液加热时它们会断裂并溶解，形成存活微晶和游离聚合物链的混合物。然而，与蛋白质纤维不同的是，冷却时不会形成新的核，只有存活的微晶会重新生长。在此，我们报告了如何在高温下捕获这些微晶，从而使我们能够研究它们在不同退火时间和添加不同量单体时的生长动力学。我们开发了一个描述这些微晶生长动力学的模型，该模型考虑了一维生长过程中伴随的断裂。我们表明，生长动力学遵循拉伸指数规律，这可能是由于聚合物分级所致。此外，通过评估胶束生长速率作为溶液中单体浓度的函数，我们可以得出胶束生长发生在单核化区域的结论。
