Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, Ohio 44106, USA.
Chemical Engineering Graduate Program (COPPE), Universidade Federal do Rio de Janeiro, Rua Horácio Macedo 2030, Cidade Universitária, Rio de Janeiro, RJ 21941-909, Brazil.
J Chem Phys. 2019 Sep 21;151(11):114907. doi: 10.1063/1.5100134.
Janus particles interfacially self-assemble into different structures when incorporated into multiphase systems. Dissipative particle dynamics simulations are employed herein to investigate the interplay between aggregation mechanisms and phase separation in polymer blends. Shorter rods with a standing configuration become increasingly "caged" or trapped in larger aggregates as weight fraction increases, which is reflected in the way that their diffusion is coupled to their aggregation rates. Janus rods of higher aspect ratios that are tilted at the interface aggregate side-by-side and are able to hinder phase separation kinetics. This is due to a combination of individual Janus rod conformations at the interface, their intrinsic aggregation mechanisms, aggregate fractal dimension, and aggregation rates, and can also be traced back to the scaling of the diffusion coefficient of aggregates with their size. Findings presented provide insight into the mechanisms governing two dimensionally growing colloidal aggregates at fluid interfaces, more specifically, those associated with Janus particles, and shed light on the potential of these systems in paving the way for designing new functional materials.
当 Janus 粒子被纳入多相体系时，它们会在界面上自组装成不同的结构。本文采用耗散粒子动力学模拟研究了聚合物共混物中聚集机制与相分离之间的相互作用。具有立构构型的较短棒状分子在重量分数增加时，会越来越“被囚禁”或被困在较大的聚集体中，这反映在它们的扩散与聚集速率的耦合方式上。界面倾斜的具有较高纵横比的 Janus 棒状分子则会并排聚集，并能够阻碍相分离动力学。这是由于界面处单个 Janus 棒的构象、它们的内在聚集机制、聚集分形维数和聚集速率的综合作用，也可以追溯到聚集体扩散系数随其尺寸的标度。研究结果为控制流体界面上二维生长胶体聚集体的机制提供了深入的了解，特别是与 Janus 粒子相关的机制，并为这些系统在为设计新型功能材料铺平道路方面的潜力提供了启示。
