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

纳米几何形状的流动在许多领域都很重要，例如在芯片生产、印刷技术和生物医学传感装置中。实验研究的重点是由地形或化学表面结构产生的纳米几何形状的非平衡流动。通过纳米级共聚物相分离产生的纳米通道，不同的表面功能（可能具有相似的空间结构）或由混合聚合物刷获得的表面梯度所给予的约束将影响流体。流动将研究含有聚合物和不同液体的溶液，从而为非平衡流动的研究提供一个可调的模型系统。通过聚合物浓度的变化来调节粘度，通过溶液源或漏的存在来控制非平衡流动。通道衬底提供了流动溶液进入通道受限空间的限制，流动通过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）的函数进行研究。表面可以通过化学反应进行修饰，以提供特定的功能。例如，疏水或亲水性行为可以实现，从而改变底物和溶液组分之间的相互作用。化学结构或梯度衬底提供了这种相互作用的空间变化，相对于纳米流体可以显示出与通道衬底相似的效果。因此，地形和化学结构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纳米级流动控制。

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.