Wetting of structured surfaces with switchable topography and mechanical properties

液体与结构表面的相互作用可以具有不同的特征——如果表面结构坚硬，地形可以决定润湿性；如果弹性力和表面张力相互比较，地形影响润湿性，液滴形状影响表面地形。根据表面结构的大小及其弹性模量的不同，表面张力或弹性力可以起主导作用——这种从弹性力的主导到弹性力和表面张力的相互作用的转变在第一个资助期进行了研究。特别是，我们开发了一种利用具有可切换机械性能和形状记忆行为的聚合物制造具有高纵横比的片层形状表面结构的方法。表面结构是否能适应液滴形状取决于聚合物的状态，我们证明了润湿性能取决于表面结构的可变形性。在第二个资助期，我们将向前迈出一步，开发具有主动可切换形貌的结构表面的新方法，并将研究弹性力和表面张力的相互作用如何影响形貌的切换和润湿行为的切换。3d打印和静电纺丝熔体电解的先进结合将用于打印复杂的结构，使用可逆膨胀和双向形状记忆聚合物。我们还将开发新的方法来获取液滴的三维形状，并将其用于研究具有可切换地形的表面上的润湿。本项目获得的实验结果将通过与spp2171其他成员合作开发的模型进行验证。

The interaction of liquids with structured surfaces can have different character - either topography can determine wetting if the surface structures are hard, or topography affects wetting and the droplet shape affects the surface topography if the elastic forces and surface tension are comparable with each other. Depending on the size of surface structures and their elastic modulus, either surfaces tension or elastic force can dominate – this transition from domination of elastic force to counteraction of elastic and surface tension force was studied in the first funding period. In particular, we developed a method for fabrication of surface structures with the shape of lamellae with high aspect ratio from polymers with switchable mechanical properties and shape memory behavior. Surface structures either could or could not adapt to the droplet shape depending on the state of the polymer, and we demonstrated that the wetting properties depend on the deformability of the surface structures. In the second funding period, we will make a step forward and develop new method for fabrication of structured surfaces with actively switchable topography and will investigate how counteraction of elastic force and surface tension will affect switching of topography and switching of wetting behavior. Advanced combination of 3D-printing and electrospinning – melt electrowriting will be used to print complex structures using reversibly swelling and two-way shape memory polymers. We will also develop new methodology for acquiring 3D shape of droplet and will use it for studying of wetting on surfaces with switchable topography. The experimental results obtained in this project will be validated by models developed in cooperation with other members of SPP 2171.