Towards the control of surface properties via nanostructured polymeric materials

该研究计划的重点是调查动态表面力（摩擦力，粘附力，表面力的时间和距离依赖性）的末端接枝带电聚合物在水介质中。 表面性质将使用表面力装置（SFA）直接测量，该装置是用于直接测量表面之间作用的分子力的最可靠的仪器之一。 尽管过去已经针对不同类别的聚合物轴承表面进行了使用SFA的几项研究，但润滑和粘附机制尚未明确阐明。缺乏系统的研究，研究聚合物的性能和环境条件对表面相互作用的影响，部分原因是难以控制的聚合物接枝密度和稳定性的接枝层的云母，这是最可靠的基板SFA测量。我们最近开发了不同的方法，允许直接共价连接到等离子体活化云母表面的聚合物与接枝密度的控制。 我们建议使用二嵌段共聚物（疏水/可离子化嵌段）共价连接到云母基板与直接键合到云母和可离子化聚合物作为最外层悬挂在水性介质中的最内层的疏水层。疏水嵌段将充当防止聚合物/云母界面处的水解反应的保护层，该界面是聚合物裂解或滑移的可能位置。通过这些方法，我们的目标是建立可靠的物理和化学性能之间的关联，最终接枝聚合物层（厚度、接枝密度、电离度、弹性、表面粗糙度、化学功能性）、环境条件（离子强度、pH值、温度、溶剂条件、压缩、剪切）和表面相互作用（摩擦力、粘附力和力的距离依赖性）。

The research program focuses on the investigation of dynamic surface forces (friction, adhesion, time- and distance-dependence of the surface forces) of end-grafted charged polymers in aqueous media. The surface properties will be directly measured using a Surface Forces Apparatus (SFA), being one of the most reliable instruments for the direct measurement of molecular forces acting between surfaces. Although several studies using SFA have been carried out in the past for different classes of polymer-bearing surfaces, the lubrication and adhesion mechanisms are not clearly elucidated. The lack of systematic studies examining the influence of polymer properties and environmental conditions on the surface interactions is in part a result of the difficulty in controlling the polymer grafting density and the stability of grafted layers on mica, which is the most reliable substrate for SFA measurements. We have recently developed different approaches allowing direct covalent attachment of polymers onto plasma activated mica surfaces with a control in the grafting density. We propose to use diblock copolymers (hydrophobic/ionizable block) covalently attached to mica substrates with an innermost hydrophobic layer directly bond to mica and the ionizable polymers as the outermost layer dangling in aqueous media. The hydropbobic block will act as a protective layer against hydrolysis reactions at the polymer/mica interface, a likely location for polymer cleavage or slip. With these approaches, we aim to establish reliable correlations between physical and chemical properties of the end-grafted polymer layers (thickness, grafting density, degree of ionization, elasticity, surface roughness, chemical functionality), environmental conditions (ionic strength, pH, temperature, solvent condition, compression, shear) and surface interactions (friction, adhesion and distance-dependence of the forces) between polymer-bearing surfaces.