Biologically inspired frictional and adhesive artificial surfaces derived from hierarchically ordered patterns of carbon nanotubes

计划中的项目将研究自然和人工系统，这些系统利用生物力学特性来增加接触力(粘附力、摩擦力)，以便可逆地附着在衬底上或在接触中防止滑动。在该项目中，有两项相互紧密联系的中心任务，一项是研究昆虫、蜘蛛和壁虎毛发附着装置的超微结构、材料特性和附着-分离性能，另一项任务是基于碳纳米管(CNTs)构建人工结构。从材料科学的角度来看，碳纳米管是模拟与壁虎脚趾结构非常相似的分级微纳米结构的最有前途的方法之一。这些实验室制造的结构将在我们的项目中以一种方式设计，它们模仿它们的自然原型-壁虎的刚毛的形态和一些特性。我们的实验室建立了碳纳米管的合成方法和高度集成的排列路线。两个主要研究领域是：(I)昆虫和壁虎刚毛附着装置的生物超微结构和力学性能的研究，以及(Ii)与排列的层状有序碳纳米管的粘附性和摩擦性能相关的合成、结构、进一步的化学修饰和实验强度研究。碳纳米管表面将通过各种测力技术进行实验测试，并将数据与在生物系统上获得的数据进行比较和优化。这种方法不仅有助于勾勒出生物系统中结构和功能之间相互关系的一般规则，而且还将允许对排列的碳纳米管结构的层级长度尺度上的基本材料性质有新的见解。这些研究将为开发具有特殊摩擦和粘合性能的新型人造表面铺平道路。计划中的合作项目的基本结果可能对操纵亚微米部件或装置具有潜在的实际影响。通常，精细的细节可以极大地提高技术系统的性能。从对生物系统的研究中，我们可以了解到，自然系统的哪些特征(尺寸和密度、头发长宽比、坡度、等级、接触的形状、头发设计的不对称性以及在附着和脱离过程中适当的移动、梯度材料的使用)对于系统在各种表面上的最佳性能至关重要。当使用碳纳米管作为自粘合表面结构的人工材料基础时，这些参数中的大多数可以改变。这种结构对可用于可逆粘合的干粘接感兴趣，或用于在重要技术领域安装或操纵微结构甚至纳米结构件的拾取贴装技术。到目前为止，仿生学的这一领域几乎没有人涉足。

The planned project will study natural and artificial systems which use biomechanical properties to increase contact forces (adhesion, friction) for reversible attachment to a substrat or for sliding prevention in contact. Within the project there are two central tasks which are strongly interconnected to each other.One task is to investigate the ultrastructure, material properties, and attachment-detachment performances in hairy attachment devices of insects, spiders, and geckos, the other task is to build artificial structures based on carbon nanotubes (CNTs). From the materials science point of view, carbon nanotubes are one of the most promising approaches to mimic hierarchical micro- and nanostructures closely resembling the gecko toe structure. These laboratory made structures will be designed in our project in a way that they mimic morphology and some properties of their natural archetype, the setae of gecko. Synthetic ways for their production and routes to align them in a highly integrated manner are established in our labs.Two main research areas, (i) studies towards the biological ultrastructure, the mechanical properties of the attachment devices of insects and gecko setae as well as (ii) the synthesis, structuring, further chemical modification and experimental strength studies related to the adhesive and frictional properties of aligned hierachically ordered CNTs are the joint research endeavour. CNT surfaces will be experimentally tested by various force measurement techniques and the data will be compared and optimized towards those obtained on the biological systems. This approach will not only aid in outlining general rules of the interrelationship between the structure and function in biological systems, but will also allow for new insights into fundamental material properties of aligned CNT structures on their hierachical length scales. Such studies will certainly pave the way to development novel artifical surfaces with particular frictional and adhesive properties.The fundamental results of the planned cooperative project may have potential practical impact for manipulating submicron parts or devices. Often fine details can dramatically improve the performance of a technological system. From studies of biological systems we can learn, which features of natural systems (dimension and density, hair aspect ratio, slope, hierarchy, shape of the contact, asymmetry of hair design combined with proper movements during attachment and detachment, use of gradient materials) are essential for optimal performance of the system on a variety of surfaces. Most of these parameters can be varied when using CNTs as artificial materials basis for self adhesive surface structures. Such structures are of interest in dry adhesion which may be used in reversible gluing, or in pick and place technologies for mounting or manipulating microstructured or even nanostructured pieces in technologically important areas. This area of bionics has been only barely touched so far.