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.

目前的研究计划将材料合成方面（激光加工、复制铸造和表面功能化）与弹性体的机械响应润湿以及铁电聚合物的电、热和压电润湿相结合。我们的研究计划侧重于动态柔性聚合物基材的润湿。为此，我们将在可拉伸聚合物的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因素控制。微米和纳米结构是使用飞秒激光以所谓的激光诱导周期性表面结构 (LIPSS) 的形式在金属母基板上产生的。然后，通过复制铸造工艺将 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连续过程将亲水性和疏水性表面基团偶联到结构化表面。在与水接触时，由于粗糙度引起的空气夹杂物，制备的样品表现出超疏水行为。拉伸样品会降低接触角，因为粗糙度会降低，并且越来越多的亲水官能团与水滴接触。随着延长的伸长，由于极性基团特定量的增加，表面变得亲水。这样，聚合物的润湿性可以通过机械变形在很宽的范围内可逆地调节。我们的第二种方法是基于极化铁电聚合物的电润湿。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释电或压电效应，可以通过温度或机械应力作为外部触发来调整接触角。接触角的起始点以及最大工作范围由 LIPSS 模型确定，该模型通过复制铸造工艺转移到聚合物上。