Ion Specifictiy at Charged Surfaces

这里提出的项目将集中在复合系统，其中包括与带电和不带电的胶体，如聚合物和纳米粒子接触的柔性膜或固体基板。这些胶体可以分散在周围的溶液中，这是吸附现象中遇到的情况，或者它们可以通过锚或接枝段附着到膜或基底上。在柔性膜的情况下，与胶体的相互作用改变膜的优选曲率并调节其粘合和内聚性质。我们在这里提出的两个具体问题是：（P1）粘附在膜上的粘性胶体，和（P2）由电荷引起的膜/胶体相互作用。实验应用是例如通过疏水性锚片段附着于膜、通过糖杯间接结合于膜或物理吸附的蛋白质。静电相互作用被认为在生物和仿生系统中起着重要作用，因为几乎所有的蛋白质都是带电的。在固体基底的情况下，吸附层对基底-胶体相互作用的依赖性和结构以及胶体溶液的性质是最重要的。我们在这里考虑的具体问题是（P3）对于带电聚合物（聚电解质）在带电基质上的吸附，额外的短程基质-聚合物吸引力的影响，以及（P4）聚合物刚性对聚合物吸附量的影响。与法德网络为这一部分提出的研究主体的联系是由于生物聚合物通常相当坚硬并且同时带电的事实。

The projects proposed here will focus on compound systems which consist of flexible membranes or solid substrates in contact with charged and uncharged colloids such as polymers and nanoparticles. These colloids may be dispersed in the surrounding solution, which is the situation encountered in adsorption phenomena, or they may be attached to the membrane or substrate by anchor or grafting segments. In the case of flexible membranes the interactions with colloids change the preferred curvature of the membranes and modulate their adhesive and cohesive properties. Two specific problems which we propose here are: (P1) Adhesive colloids which stick to the membranes, and (P2) Membrane/colloid interactions arising from electric charges. Experimental applications are for example proteins which are either attached to a membrane via hydrophobic anchor segments, bound indirectly to the membrane through the glycocalix, or physisorbed. Electrostatic interactions supposedly play an important role in biological and biomimetic systems, since almost all proteins are charged. In the case of solid substrates, the dependence and structure of the adsorption layer on the substrate-colloids interaction and the properties of the colloidal solution are of prime interest. The specific problems we have in mind here are (P3) The influence of additional short-ranged substrate-polymer attraction for the adsorption of charged polymers (polyelectrolytes) on charged substrates and (P4) The influence of polymer rigidity on the adsorption behaivor of polymers. The connection to the main-body of research proposed in the French-German Network for this part results from the fact that biopolymers are in general rather stiff and charged at the same time.