Rudyak Vladimir Yu, Kozhunova Elena Yu, Chertovich Alexander V
Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia.
Semenov Institute of Chemical Physics, Moscow, 119991, Russia.
Sci Rep. 2019 Sep 10;9(1):13052. doi: 10.1038/s41598-019-49512-3.
In this paper we propose a new method of coarse-grained computer simulations of the microgel formation in course of free radical precipitation polymerization. For the first time, we simulate the precipitation polymerization process from a dilute solution of initial components to a final microgel particle with coarse grained molecular dynamics, and compare it to the experimental data. We expect that our simulation studies of PNIPA-like microgels will be able to elucidate the subject of nucleation and growth kinetics and to describe in detail the network topology and structure. Performed computer simulations help to determine the characteristic phases of the growth process and show the necessity of prolongated synthesis for the formation of stable microgel particles. We demonstrate the important role of dangling ends in microgels, which occupy as much as 50% of its molecular mass and have previously unattended influence on the swelling behavior. The verification of the model is made by the comparison of collapse curves and structure factors between simulated and experimental systems, and high quality matching is achieved. This work could help to open new horizons in studies that require the knowledge of detailed and realistic structures of the microgel networks.
在本文中，我们提出了一种新的粗粒度计算机模拟方法，用于研究自由基沉淀聚合过程中的微凝胶形成。我们首次使用粗粒度分子动力学模拟了从初始组分的稀溶液到最终微凝胶颗粒的沉淀聚合过程，并将其与实验数据进行比较。我们期望对类聚N-异丙基丙烯酰胺（PNIPA）微凝胶的模拟研究能够阐明成核和生长动力学问题，并详细描述网络拓扑结构。所进行的计算机模拟有助于确定生长过程的特征阶段，并表明延长合成时间对于形成稳定微凝胶颗粒的必要性。我们证明了微凝胶中悬垂端的重要作用，其占微凝胶分子质量的50%之多，且此前对溶胀行为有未被关注的影响。通过比较模拟系统和实验系统的塌陷曲线及结构因子对模型进行验证，实现了高质量匹配。这项工作有助于为那些需要了解微凝胶网络详细且真实结构的研究开辟新的视野。
