Geometry and kinetics determine the microstructure in arrested coalescence of Pickering emulsion droplets
Geometry and kinetics determine the microstructure in arrested coalescence of Pickering emulsion droplets
复制标题
几何学和动力学确定皮克林乳液液滴滞留聚结的微观结构
DOI：
10.1039/c9sm00435a
复制
发表时间：
2019
期刊：
影响因子：
3.4
通讯作者：
Atherton, Timothy J.
中科院分区：
文献类型：
--
作者：
Xie, Zhaoyu;Burke, Christopher J.;Mbanga, Badel;Spicer, Patrick T.;Atherton, Timothy J.
聚结受阻发生在皮克林乳液中，其中吸附在液滴表面上的胶体颗粒变得拥挤并抑制液滴形状的松弛和进一步聚结。所得到的液滴具有不均匀的曲率分布，并且取决于初始覆盖率，可以在桥接两个液滴的颈部周围并入具有负高斯曲率的区域。在这里，我们解决的曲率和动力学过程的逮捕的微观结构的最终状态的相对影响。在准静态情况下，缺陷的诱导和分布，以屏蔽高斯曲率。相反，如果每个颗粒的面积变化率超过颗粒的扩散常数，则不断变化的表面会引起局部固化，这让人想起在其他胶体系统中观察到的堵塞前沿。在这个制度中，最终的结构被证明是强烈的压缩历史之前逮捕，这可以预测从外在的几何形状的序列的表面相比，内在的几何形状，统治的静态制度。
Arrested coalescence occurs in Pickering emulsions where colloidal particles adsorbed on the surface of the droplets become crowded and inhibit both relaxation of the droplet shape and further coalescence. The resulting droplets have a nonuniform distribution of curvature and, depending on the initial coverage, may incorporate a region with negative Gaussian curvature around the neck that bridges the two droplets. Here, we resolve the relative influence of the curvature and the kinetic process of arrest on the microstructure of the final state. In the quasistatic case, defects are induced and distributed to screen the Gaussian curvature. Conversely, if the rate of area change per particle exceeds the diffusion constant of the particles, the evolving surface induces local solidification reminiscent of jamming fronts observed in other colloidal systems. In this regime, the final structure is shown to be strongly affected by the compressive history just prior to arrest, which can be predicted from the extrinsic geometry of the sequence of surfaces in contrast to the intrinsic geometry that governs the static regime.