Magneto-responsive surfaces for controlling dynamics of wetting and drop impact (SANDPIT)

用于控制润湿和跌落冲击动态的磁响应表面 (SANDPIT)

• 批准号: 524921900
• 负责人: Professor Dr. Mikhail Chamonine
• 金额: --
• 依托单位: Fakultät Elektro- und Informationstechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/524921900?language=en
• 关键词: Magneto; responsive; surfaces; controlling; dynamics; Magneto; responsive; surfaces; controlling; dynamics

Magneto-responsive surfaces (MRSs) have recently attracted attention of researchers because they provide a remote, nondestructive and real-time (dynamic) approach for controllable manipulation of nonmagnetic liquids. Prospective technological applications range from droplet-based microfluidics, microreactors, and liquid distributors, to fog harvesting etc. Hitherto, the dynamic wetting of MRSs remained out of the scope of research. The project aims to explore the potential of MRSs, based on soft magneto-active elastomers (MAEs) to understand and tune their wetting properties and drop splashing. MAEs are composite materials comprising micro- and nanometer-sized ferromagnetic particles embedded into a compliant polymer (in our case polydimethylsiloxane) matrix. We plan i) to investigate magnetic field-based regulation of wetting and drop splashing on non-structured MAE surfaces and ii) to investigate magnetic field-based regulation of wetting and drop splashing on microstructured MAE surfaces. i) Application of a magnetic field of a few hundred mT, perpendicular to MAE film surfaces, leads to the increase (switch) in the dynamic shear modulus over a few orders of magnitude and to the significant increase in the surface roughness. Furthermore, the magnetic-field-induced plasticity effect of MAEs allows one to retroactively smoothen or even modulate the roughness of the MAE surface on the micrometer scale. This makes MAEs promising candidates for separate elucidation of the effects of surface topography and the mechanical properties on switching of wetting properties. For this purpose, we will study unstructured MAE surfaces with different material composition and initial surface roughness, leading to the variable material stiffness and responsivity to a magnetic field. ii) We will study effects of magnetic-field-induced switching of surface topography on MAE surfaces textured with lamellar and pillared microstructures. A magnetic field which is not parallel to the protrusion direction of surface structures leads to their bending and therefore, drastically changes the surface topography. The effects of deflection of flexible microstructures with a high aspect ratio due to capillary forces will be also explored. The special feature of our approach is the usage of tilted microstructures from soft MAEs that may lead to asymmetry of drop spreading. Finally, we will study drop impact on MAE surfaces to unveil the relationships between micro- and macro-scale processes, related to fast contact line motion, and the outcome of drop impact (deposition / bouncing / splash).

磁反应表面（MRSS）最近引起了研究人员的注意，因为它们提供了一种远程，无损和实时（动态）方法，可控制非磁性液体。前瞻性技术应用范围从基于液滴的微流体，微反应器和液体分销商到雾收集等。该项目旨在基于软磁性弹性体（MAE）来探索MRSS的潜力，以了解和调整其润湿性能并滴落。 MAE是包含微型和纳米尺寸的铁磁颗粒的复合材料，这些颗粒嵌入了符合符合的聚合物（在我们的情况下是聚二甲基硅氧烷）基质中。我们计划I）研究基于磁场的润湿和滴落在非结构化MAE表面上的调节，以及II）研究基于磁场的调节微观结构MAE表面上的润湿和滴落的调节。 i）在垂直于MAE膜表面的几百个MT的磁场上施加，导致动态剪切模量在几个数量级上增加（开关），并且表面粗糙度的显着增加。此外，MAE的磁场诱导的可塑性效果使人们可以追溯平滑甚至调节MAE表面在微米尺度上的粗糙度。这使MAE有希望的候选人单独阐明表面地形的影响以及机械性能对润湿性能开关的影响。为此，我们将研究具有不同材料组成和初始表面粗糙度的非结构化MAE表面，从而导致材料刚度和对磁场的响应性的可变。 ii）我们将研究磁场诱导的表面地形切换对用层状和柱状微结构质感的MAE表面的影响。与表面结构的突起方向平行的磁场会导致其弯曲，因此会大大改变表面形貌。还将探索具有毛细管力引起的高纵横比的挠性微观结构的偏转影响。我们方法的特征是使用软MAE的倾斜微观结构的使用可能导致跌落散布的不对称性。最后，我们将研究对MAE表面的下降影响，以揭示与快速接触线运动以及跌落撞击结果（沉积 /弹跳 /飞溅）有关的微观和宏观尺度过程之间的关系。