Influence of surface topography and chemistry on the wetting behavior of laser-patterned, metallic surfaces

表面的润湿行为对其抗菌性能、摩擦磨损性能或附着力有很大的影响。激光图案化的过程允许系统地改变表面的润湿特性。能量的局部施加改变了金属表面的表面化学和表面形貌，而表面化学和表面形貌对润湿性能都有影响。特别是，应借助实验和模拟方法来确定相关的关键参数。第一个目标是产生和表征激光图案化的铜样品，并创建合适的模拟模型。对于激光构图，使用了极其精确和高效的直接激光干涉构图(DLIP)方法。采用了三种不同的脉冲激光系统(ns、ps、fs)，通过利用不同的激光材料相互作用来获得不同的表面化学结构，这些表面化学成分与脉冲宽度有关。首先，不均匀表面化学的影响将通过溅射过程来均衡化。将使用高分辨率技术分析所产生的样品的形貌和表面化学，以创建合适的模拟模型。采用了三种不同的方法：能量最小化、粗粒分子动力学(MD)模拟和全原子分子动力学模拟。此外，化学均质表面的润湿行为是通过宏观和一种专门开发的具有高空间分辨率的方法(偏最小二乘算法)来确定的。第二个目标是用上述方法模拟化学均质样品的润湿行为。我们将研究初级激光图案、表面化学和叠加纳米粗糙度的影响。此外，还将比较连续介质模拟和分子动力学模拟，这是进一步多尺度建模的重要前提。最终目标是确定激光图案化、化学非均匀表面润湿的关键参数，并将实验和模拟进行比较。特别是，将评估模拟方法的可预测性和所需的计算工作量。这是激光图案化金属表面润湿行为领域的一个里程碑，因为到目前为止相关文献还没有达成共识。

The wetting behavior of surfaces has drastic effects on their antimicrobial, friction and wear properties, or their adhesion. The process of laser patterning allows to change the wetting properties of surfaces systematically. The local application of energy modifies both the surface chemistry and the topography, which both have an influence on the wetting properties.The present proposal systematically investigates the influence of laser patterning of metallic surfaces on their wetting properties. In particular, the relevant key parameters shall be identified with the aid of experimental and simulative methods.The first goal is the generation and characterization of laser-patterned copper samples and the creation of suitable simulation models. For laser patterning, the extremely precise and efficient method of Direct Laser Interference Patterning (DLIP) is used. Three different pulsed laser systems (ns, ps, fs) are used in order to obtain different surface chemistry with similar topography by exploiting the varying laser material interaction, which depends on the pulse duration. First, the effect of an inhomogeneous superficial chemistry is to be egalized by sputtering processes. The resulting topography and surface chemistry of the produced samples will be analyzed using high resolution techniques in order to create suitable simulation models. Three different approaches are used: energy minimization, coarse grained molecular dynam-ics (MD) simulations, and fully atomistic MD simulations. Furthermore, the wetting behavior of the chemically homogeneous surfaces is determined both macroscopically and by a specially developed method (Partial Least Squares Algorithm) with high spatial resolution.The second goal is the simulation of the wetting behavior of the chemically homogeneous samples with the above mentioned methods. The influence of the primary laser pattern, the surface chemistry, and a superimposed nano-roughness will be investigated. Furthermore, continuum approach and MD simulations will be compared, which is an important prerequisite for further multi-scale modelling.The final goal is to identify the key parameters in the wetting of laser-patterned, chemically inhomogeneous surfaces and to compare experiment and simulation. In particular, the pre-dictability and the required calculation effort of the simulation methods will be evaluated.This is a milestone in the field of the wetting behavior of laser-patterned metallic surfaces, as there is no consensus in the relevant literature so far.