Discrete Element Model for Suppression of Coffee-Ring Effect

• DOI: 10.1038/srep42817
• Publication Date: 2017-02-20T10:07:48Z
• Authors: Ting Xu; Miu Ling Lam; Ting-Hsuan Chen
• Keywords: 11. Sustainability; 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences; Article

When a sessile droplet evaporates, coffee-ring effect drives the suspended particulate matters to edge, eventually forming ring-shaped deposition. Because it causes non-uniform distribution of solid contents, which is undesired in many applications, attempts have been made eliminate effect. Recent reports indicated that can be suppressed by mixture spherical and non-spherical particles with enhanced particle-particle interaction at air-water interface. However, model comprehend inter-particulate activities has lacking. Here, we report discrete element (particle system) investigate phenomenon. The modeled dynamics included particle traveling following capillary flow Brownian motion, its resultant 3D hexagonal close packing along contact line. For being adsorbed interface, cluster growth, deformation, combination. We found suppression does not require circulatory driven an inward Marangoni Instead, number new formation, increasing ratio overall microspheres, more dominant process. Together, this provides useful platform elucidating insights for suppressing practical applications future.