Department of Earth Science and Engineering, Imperial College London, London, United Kingdom.
J Colloid Interface Sci. 2011 Sep 1;361(1):370-80. doi: 10.1016/j.jcis.2011.05.061. Epub 2011 May 26.
The effects of shape and contact angle on the behaviour of orthorhombic particles at an interface and in thin films were investigated using Surface Evolver. It is shown that the energetically stable orientations of the particle change with its aspect ratio. Long, wide, flat particles with low contact angles are more stable in flat orientations, i.e. with two faces parallel to the flat film surface. More cubic particles with higher contact angles are more stable in twisted orientations, where the opposite sides of the film can be drawn together at the sharp edges of the particle. The combination of contact angle and orientation has been found to have a large effect on the capillary pressure required to rupture the film. A film containing a particle in a flat orientation will rupture at a capillary pressure up to three times greater than one containing an identical particle in a twisted orientation. Wider, flatter particles with low contact angles stabilise thin liquid films to a greater extent than cubic particles with high contact angles.
使用 Surface Evolver 研究了形状和接触角对界面和薄膜中正交粒子行为的影响。结果表明，颗粒的稳定取向随其纵横比而变化。具有低接触角的长、宽、平的粒子在平面取向中更稳定，即两个面平行于平面薄膜表面。具有较高接触角的更立方的粒子在扭曲取向中更稳定，在这种取向中，薄膜的相对侧可以在粒子的尖锐边缘处靠拢。发现接触角和取向的组合对破裂薄膜所需的毛细压力有很大影响。在一个平面取向的粒子的薄膜中，破裂所需的毛细压力高达在扭曲取向的薄膜中破裂所需压力的三倍。具有低接触角的更宽、更平的粒子比具有高接触角的立方粒子更能稳定薄液膜。
