Tuning Adhesion by Surface Modification with Mixed Polymer Brushes

聚合物-固体界面的粘附性在从微电子到飞机工业的许多应用中都是非常重要的。无论是对永久粘接还是可逆粘合，基材的化学成分和形态都必须得到完美的控制。该项目旨在开发基于化学非均质可切换薄膜的新一代适应性表面，这种薄膜可共价结合到固体衬底上，从而以一种可控和可重复的方式改变其表面化学。这种薄膜最近是由两种不相容的聚合物材料制成的，一端系在衬底上(混合聚合物刷子)。这些混合电刷因环境的不同而发生相分离，导致表面形态和表面能态发生显着变化。该项目旨在研究混合刷子的切换现象对这种表面可以与粘结剂形成的界面强度的影响。这些表面将对调整软胶粘剂的粘合性能特别有用。这类胶粘剂因其低毒和使用方便，在工业和医学领域受到越来越多的关注。了解这类胶粘剂的主要要求，能够实现对不同基材的可逆、快速和轻松的粘接。我们计划在受控环境中制备具有适应性和可切换粘接性能的聚合物薄膜。混合刷状层将通过“接枝”和“接枝”两种方法制备。利用椭偏仪、XPS、XPEEM、FTIR/ATR、接触角和原子力显微镜等测试手段对可适应和可切换附着力的功能薄膜进行了定量表征。这种表面改性对胶粘剂和摩擦性能的影响将通过使用原子力显微镜的纳米断裂测试和弹性胶粘剂的探针测试来研究。德国集团提供薄膜制备、表面化学和表面表征领域的专业知识，法国集团提供粘合剂性能的机械测量和表征领域的专业知识。

Adhesion at polymer-solid interfaces is of great importance for numerous applications from microelectronics to aircraft industry. It is essential, for permanent as well as for reversible adhesion, that the substrate's chemical composition and morphology is perfectly controlled. The project aims at the development of a new generation of adaptative surfaces based on chemically heterogeneous switchable thin polymer films, which covalently bond to a solid substrate, modifying therefore its surface chemistry in a well-controlled and reproducible way. Such films were recently fabricated from two incompatible polymer materials tethered at one end to the substrate (mixed polymer brushes). Those mixed brushes undergo phase segregation depending on environment resulting in a remarkable switching of morphology and surface energetic state. The project aims to study the influence of the switching phenomenon of mixed brushes on the strength of the interface which such a surface can form with an adhesive. These surfaces will be particularly useful to tune the adhesive properties of soft adhesives. This class of adhesives is gaining increasing interest in industry and medicine for its low toxicity and ease of use. Knowing the main requirements for such adhesives provides the capability to generate reversible, fast and easy adhering bonds to different substrates. We plan to prepare polymer films with adapting and switchable adhesive properties in a controlled environment. The mixed brush-like layers will be fabricated with "grafting to" and "grafting from" methods. Functional thin films for adapting and switchable adhesion will be quantitatively characterized with ellipsometry, XPS, XPEEM, FTIR/ATR, contact angle and AFM measurements. The consequences of this surface modification on adhesive and frictional properties will be investigated by a nano fracture test utilizing AFM and a probe test for elastomeric adhesives. The German group provides expertise in the area of film preparation, surface chemistry and surface characterization and the French group contributes expertise in the area of mechanical measurements and characterization of adhesive properties.