Delamination of drying nanoparticle suspensions
Delamination of drying nanoparticle suspensions
复制标题
干燥纳米颗粒悬浮液的分层
DOI：
10.1039/c1sm05734k
复制
发表时间：
2011
期刊：
影响因子：
3.4
通讯作者：
Mahesh S. Tirumkudulu
中科院分区：
文献类型：
--
作者：
Arijit Sarkar;Mahesh S. Tirumkudulu
胶体分散体在细毛细血管中干燥，呈现出一组迷人的裂缝。在这里，我们提出的实验中，裂缝之前是分层，其中颗粒堆积区域从毛细管壁开裂前。在不同蒸发速率范围和两种不同大小的毛细管上进行的实验表明，存在一个较高的临界毛细管压力，在这个压力下分层会自发发生，而在较低的临界压力下，分层的传播锋会被阻止。测量结果显示，干燥过程中毛细血管壁发生亚微米级的偏转。我们将分层过程建模为储存在应力粒子网络中的弹性能量与毛细管变形壁面之间的竞争，并且随着分层锋面的推进，表面能量增加。预测的毛细壁变形和毛细脱层临界压力与观测值基本一致。
Colloidal dispersions dried in thin capillaries exhibit a fascinating array of cracks. Here, we present experiments where the cracks are preceded by delamination in which the particle packed region debonds from the walls of the capillary before cracking. Experiments over a varying range of evaporation rates and with two differently sized capillaries show that there exists an upper critical capillary pressure at which the delamination occurs spontaneously and a lower critical pressure at which the propagating delamination front is arrested. Measurements reveal sub-micron deflection of the capillary walls during drying. We model the delamination process as a competition between the elastic energy stored in the stressed particle network and the deformed walls of the capillary, and the surface energy increase when the delamination front advances. The predicted deformation of the capillary walls and the critical capillary pressure for delamination are in fair agreement with the observations.