Colloidal assembly as a tool for adaptive and switchable interfaces

点击翻译按钮获取中文摘要

This project will contribute to the fundamental understanding of dynamic wetting and dewetting processes on flexible, adaptive and even switchable substrates by means of lattice Boltzmann simulations and simple analytical models. Our aim is to propose strategies utilizing colloidal assembly at fluid interfaces to generate “substrates” with complex geometrical and wetting properties. We will base on recent advances in the synthesis and control of colloids which led to the availability of particles with highly specific features such as well-defined shapes and surface properties together with the ability to manipulate them by external forces and fields. An example for such particles are patchy particles or Janus particles which depict a variation of their surface properties in dependence on the position. They can even be stimuli responsive or react to external magnetic and electric fields, light or changes in the properties of the surrounding fluids. Attached to a fluid interface, these abilities render them interesting candidates to create interfaces which adopt to the surrounding liquid species or can be switched by means of external fields. For example, due to external forces, a collection of microscale Janus particles with hydrophobic and hydrophilic hemispheres might rotate at the interface and thus dynamically change the macroscale wetting properties of the interface. Alternatively, these particles might be let rotate freely at the interface so that they can optimize the wetting properties by simply minimizing their surface energy. We will investigate such systems systematically by simulating the spreading and wetting dynamics of droplets on various interfaces: A pure liquid interface, an interface covered with particles with defined homogeneous wettability and geometry, and particles with anisotropic shape and wetting properties. At last, we will investigate how to “switch” particle-laden interfaces by means of external fields.