A droplet of nanoparticle suspension is deposited on a specially designed dual wettable surface. Half diagonal of SiO₂ substrate was oil coated and other half stayed unchanged. The droplet forms contact angle of 35^∘ on the unchanged dry portion whereas it reaches to 60^∘ on the oil coated region. Nanoparticle dried in stick–slip fashion where such effect was more pronounced on the oil-wet region. Scanning electron microscope (SEM) images revealed large ribbon-like nanorod assembly on the dry-region and short monolayer ribbons on the oil-wet part of the substrate. On both surfaces, shape-separation effect produced rod-rich and sphere-rich regions. The assemblies formed over the dry portion were dense whereas significantly small number of nanoparticles were observed on the oil-wet region. The droplet contact-line remained partially dynamic owing to the dual wettable design of the surface. Such contact-line dynamics facilitated the shape-separation effect induced by the surfactant molecules and dictated the deposition process over the surface. This work will be helpful to study shape-separation effect of small biological entities and multisystem of nanoparticles.

一滴纳米颗粒悬浮液沉积在专门设计的双可润湿表面上。SiO ₂基材的一半对角线涂有油，另一半保持不变。液滴在未改变的干燥部分形成 35 ^{∘ 的}接触角，而达到 60 ^∘在涂油区域。纳米颗粒以粘滑方式干燥，这种效果在油湿区域更为明显。扫描电子显微镜 (SEM) 图像显示干燥区域上的大带状纳米棒组件和基材的油湿部分上的短单层带。在两个表面上，形状分离效应产生了富含棒和富含球体的区域。在干燥部分上形成的组件是致密的，而在油湿区域上观察到的纳米颗粒数量非常少。由于表面的双重可湿性设计，液滴接触线保持部分动态。这种接触线动力学促进了表面活性剂分子引起的形状分离效应，并决定了表面上的沉积过程。