Non-equilibrium flow at gradient surfaces: Fluid kinetics of droplets and particle motion

纳米级几何形状中的流动在许多领域中是重要的，例如在芯片生产、印刷技术和生物医学传感装置中。实验研究的重点是在纳米几何形状的非平衡流将产生的地形或化学表面结构。流体将受到由纳米通道给出的限制的影响，纳米通道通过共聚物的纳米级相分离产生，通过不同的表面官能度，其可以类似地空间结构化，或通过表面梯度，其用混合聚合物刷获得。流动将与含有聚合物和不同液体的溶液进行研究，从而为非平衡流的研究提供了一个可调的模型系统。通过聚合物浓度的变化来调节粘度，并且通过溶液的源或漏的存在来控制非平衡流动。镶嵌基板提供了一个限制的流动的解决方案到有限的空间的通道和流动的微观和散射技术作为控制参数，如通道宽度，通道粗糙度或通道形态的函数进行了研究。表面可以通过化学反应改性以提供特定的功能。例如，可以实现疏水或亲水行为，从而改变基质和溶液组分之间的相互作用。化学结构化或梯度衬底提供了这种相互作用的空间变化，其相对于纳米流体可以显示出与带通道衬底类似的效果。因此，地形和化学结构的功能化模型表面将比较它们对聚合物溶液和混合液体的纳米流体的影响，以提供更好的理解和可能的控制在纳米级的流动。

Flow in nanoscale geometries is of importance in many areas as for example in chip production, printing techniques and bio-medical sensing devices. The experimental investigation focuses on non-equilibrium flow in nanoscale geometries to be generated by topographic or chemical surface structuring. The fluidics will be influenced by confinement given by nano-channels, which are produced via nano-scale phase separation of copolymers, by different surface functionalities, which may be similarly spatially structured, or by surface gradients, which are obtained with mixed polymer brushes. Flow will be investigated with solutions containing polymers and different liquids thus providing a tunable model system for the investigation of non-equilibrium flow. By variation of polymer concentration the viscosity is adjusted, and by the presence of a source or drain for the solution the non-equilibrium flow is controlled. Channeled substrates provide a confinement of the flowing solution into the restricted space of the channels and flow is investigated by microscopic and scattering techniques as a function of control parameters such as channel width, channel roughness or channel morphology. The surface can be modified by chemical reaction to provide specific functionality. For instance hydrophobic or hydrophilic behavior can be achieved, thus changing interaction between substrate and components of the solution. Chemically structured or gradient substrates provide a spatial variation of this interaction which with respect to nanofluidics could show a similar effect as channeled substrates. Thus both topographic and chemically structured functionalized model surfaces will be compared with respect to their influence on nanofluidics of polymer solutions and mixed liquids to provide a better understanding and possibly control of flow at nanoscopic level.