Mechano-responsive and dynamic electro-wetting of replica-casted laser-induced periodic surface structures

复制铸造激光诱导周期性表面结构的机械响应和动态电润湿

• 批准号: 470373333
• 负责人: Professor Dr.-Ing. Frank. A. Müller
• 金额: --
• 依托单位: Lehrstuhl für Oberflächen- und Grenzflächentechnologien
• 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/470373333?language=en
• 关键词: Mechano; responsive; dynamic; electro; wetting

The present research proposal combines material synthesis aspects (laser processing, replica casting, and surface functionalization) with the mechano-responsive wetting of elastomers and the electro-, pyro-, and piezo-wetting of ferroelectric polymers.Our research proposal focuses on the dynamic wetting of flexible polymer substrates. For this purpose we will realize specific micro- and nanostructures on the surface of stretchable polymers. The wetting behavior is controlled by surface functionalization and various external triggers. The micro- and nanostructures are produced on a metallic master substrate in the form of so-called laser-induced periodic surface structures (LIPSS) using an fs-laser. The LIPSS model is then transferred to flexible and stretchable polymer samples in a replica casting process.In a first approach, hydrophilic and hydrophobic surface groups are coupled to the structured surface by a sequential process of hydroxylation and selective silanization. In contact with water the prepared samples show superhydrophobic behaviour due to roughness induced air inclusions. Stretching the specimen reduces the contact angle as roughness is reduced and an increasing number of hydrophilic functional groups come into contact with the water drop. With prolonged elongation, the surface becomes hydrophilic due to the increasing specific amount of polar groups. In this way, the wettability of the polymer can be reversibly adjusted over a wide range by mechanical deformation.Our second approach is based on the electro-wetting of polarized ferroelectric polymers. Here the contact angle can be controlled by an external voltage between the water drop and the substrate. Based on the pyro or piezoelectric effect of the selected polymer, the contact angle can be adjusted by temperature or mechanical stress as an external trigger. The starting point of the contact angle and thus the maximum working range is determined by the LIPSS model, which is transferred to the polymer by the replica casting process.

目前的研究方案结合材料合成方面（激光加工，复制铸造，表面功能化）与弹性体的机械响应润湿和电，热，压电铁电聚合物wetting.Our研究方案侧重于柔性聚合物基板的动态润湿。为此，我们将在可拉伸聚合物表面实现特定的微米和纳米结构。润湿行为由表面功能化和各种外部触发器控制。使用fs激光器在金属主基底上以所谓的激光诱导周期性表面结构（LIPSS）的形式产生微米和纳米结构。然后，在复制铸造过程中将LIPSS模型转移到柔性且可拉伸的聚合物样品上。在第一种方法中，通过羟基化和选择性硅烷化的顺序过程将亲水性和疏水性表面基团偶联到结构化表面。在与水接触，制备的样品显示超疏水行为，由于粗糙度引起的空气夹杂物。拉伸试样会降低接触角，因为粗糙度降低，并且越来越多的亲水性官能团与水滴接触。随着延长的伸长，由于极性基团的特定量增加，表面变得亲水。第二种方法是基于极化铁电聚合物的电润湿性。这里，接触角可以通过水滴和基底之间的外部电压来控制。基于所选聚合物的热电效应或压电效应，接触角可以通过温度或机械应力作为外部触发来调节。接触角的起始点和最大工作范围由LIPSS模型确定，该模型通过复制铸造工艺转移到聚合物上。