Bourrianne Philippe, Lilin Paul, Sintès Guillaume, Nîrca Traian, McKinley Gareth H, Bischofberger Irmgard
Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
Soft Matter. 2021 Oct 13;17(39):8832-8837. doi: 10.1039/d1sm00832c.
A drop of an aqueous suspension of nanoparticles placed on a substrate forms a solid deposit as it dries. For dilute suspensions, particles accumulate within a narrow ring at the drop edge, whereas a uniform coating covering the entire wetted area forms for concentrated suspensions. In between these extremes, we report two additional regimes characterized by non-uniform deposit thicknesses and by distinct crack morphologies. We show that both the deposit shape and the number of cracks are controlled exclusively by the initial particle volume fraction. The different regimes share a common avalanche-like crack propagation dynamics, as a result of the delamination of the deposit from the substrate.
将一滴纳米颗粒水悬浮液置于基底上，干燥时会形成固体沉积物。对于稀悬浮液，颗粒在液滴边缘的窄环内聚集，而浓悬浮液则会形成覆盖整个湿润区域的均匀涂层。在这两种极端情况之间，我们报告了另外两种状态，其特征是沉积物厚度不均匀且裂纹形态各异。我们表明，沉积物形状和裂纹数量均仅由初始颗粒体积分数控制。由于沉积物与基底分层，不同状态具有共同的类似雪崩的裂纹扩展动力学。
