Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology , Gotthard-Franz-Straße 3, 76131 Karlsruhe, Germany.
Department of Chemical Engineering, KU Leuven , Celestijnenlaan 200f, 3001 Leuven, Belgium.
ACS Appl Mater Interfaces. 2017 Mar 29;9(12):11095-11105. doi: 10.1021/acsami.6b13624. Epub 2017 Mar 14.
Cracks, formed during the drying of particulate films, can reduce the effectiveness or even render products useless. We present a novel, generic approach to suppress crack formation in thin films made from hard particle suspensions, which are otherwise highly susceptible to cracking, using the capillary force between particles present when a trace amount of an immiscible liquid is added to a suspension. This secondary liquid preserves the particle cohesion, modifying the structure and increasing the drying rate. Crack-free films can be produced at thicknesses much greater than the critical cracking thickness for a suspension without capillary interactions, and even persists after sintering. This capillary suspension strategy is applicable to a broad range of materials, including suspensions of metals, semiconductive and ceramic oxides, or glassy polymeric particles, and can be easily implemented in many industrial processes since it is based on well-established unit operations. Promising fields of application include ceramic foils and printed electronic devices.
裂缝是在颗粒膜干燥过程中形成的，会降低产品的有效性，甚至使其变得毫无用处。我们提出了一种新颖的通用方法，通过在悬浮液中添加微量不混溶液体来利用存在的颗粒之间的毛细力，从而抑制由硬颗粒悬浮液制成的薄膜中出现裂缝，否则这些薄膜很容易出现裂缝。这种二次液体保持了颗粒的内聚力，改变了结构并提高了干燥速率。即使在烧结后，也可以在比没有毛细相互作用的悬浮液的临界开裂厚度大得多的厚度下生产无裂缝的薄膜。毛细悬浮液策略适用于广泛的材料，包括金属、半导体和陶瓷氧化物或玻璃状聚合物颗粒的悬浮液，并且由于它基于成熟的单元操作，因此可以很容易地应用于许多工业过程。有前途的应用领域包括陶瓷箔和印刷电子设备。
