Substrate and Drop Dynamics During Impact and Coalescence on Soft Adaptive Surfaces

软自适应表面冲击和合并过程中的基材和跌落动力学

• 批准号: 422792849
• 负责人: Dr. Kirsten Harth
• 金额: --
• 依托单位: Fachbereich Technik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/422792849?language=en
• 关键词: Substrate; Drop; Dynamics; During; Impact

Droplets impacting on soft materials are frequently encountered ineveryday life, e.g. water drops on skin during showering, dropsimpacting on fresh paint or on plant leaves, or simply drops impacting onto a previously wetted surface. Such systems often consist of a (thin) soft and adaptive surface layer on a stiff substrate. The soft layer, however thin, can crucially alter the behavior of contact lines, and particularly of droplets, on microscopic and macroscopic scales. Contrasting to this, research so farmainly focused on hard surfaces, liquid pools and miscible liquid surface layers (of usually non-microscopic depth). The coupled problem of static shapes of a droplet on visco-elastic substrates has been modeled extensively, and comparatively slow processes of contact line motion have been addressed. Recent research develops more towards studies of the interaction ofsoft substrates with rapidly moving contact lines, as e.g. encountered during drop impact. However, in those studies, the dynamics of the substrate, while it is the actual reason for all changes of the macroscopic contact line and droplet behavior, the actual substrate dynamics is not recorded and not analyzed – measuring the microscopic deformations of thin surface layers during rapid processes requires substantial experimental effort and sophisticated, new techniques. My project deals with two exemplary processes, drop impact on soft flexible layers and drop coalescence on fluid layers of limited depth. The substrates may consist of viscous, or viscoelastic liquids, or of viscoelastic gels. Standard side and top / bottom view high-speed imaging will be combined with a number of non-standard high-speed bottom view techniques,providing access to the substrate's deformations, strains or contact formation processes of the surface with the liquid, as well as possibly entrained microscopic gas layers. My setup and expertise will beavailable to the other participating groups of SPP-2171 throughcollaboration, currently planned for several adaptive substrates. I willcollaborate with theoreticians on analytical and numerical modeling ofmy experiments.

在日常生活中，经常会遇到水滴撞击软材料的情况，例如，淋浴时水滴落在皮肤上，水滴撞击新鲜油漆或植物叶片上，或者仅仅是水滴撞击到先前润湿的表面上。这样的系统通常包括在刚性基底上的（薄的）柔软且自适应的表面层。无论多么薄，软层都可以在微观和宏观尺度上关键地改变接触线的行为，特别是液滴的行为。与此相反，迄今为止的研究主要集中在硬表面，液体池和可混溶液体表面层（通常非微观深度）。粘弹性基底上的液滴的静态形状的耦合问题已经被广泛地建模，并且已经解决了接触线运动的相对缓慢的过程。最近的研究发展更多的研究软基板与快速移动的接触线的相互作用，例如在跌落冲击过程中遇到的。然而，在这些研究中，基板的动力学，虽然它是宏观接触线和液滴行为的所有变化的实际原因，但实际的基板动力学没有记录和分析-在快速过程中测量薄表面层的微观变形需要大量的实验努力和复杂的新技术。我的项目涉及两个典型的过程，软柔性层上的液滴冲击和有限深度的流体层上的液滴聚结。基底可以由粘性或粘弹性液体或粘弹性凝胶组成。标准的侧视图和俯视图/仰视图高速成像将与许多非标准的高速仰视图技术相结合，提供对基板的变形、应变或表面与液体的接触形成过程以及可能夹带的微观气体层的访问。我的设置和专业知识将通过合作提供给SPP-2171的其他参与小组，目前计划用于几个自适应衬底。我将与理论家合作，对我的实验进行分析和数值建模。