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（附着力、摩擦力），以实现与基体的可逆附着或防止接触时滑动。在这个项目中，有两个中心任务彼此紧密相连。一项任务是研究昆虫、蜘蛛和壁虎毛状附着装置的超微结构、材料性能和附着-脱离性能；另一项任务是构建基于碳纳米管（CNTs）的人工结构。从材料科学的角度来看，碳纳米管是模拟类似壁虎脚趾结构的分层微纳米结构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模仿其自然原型的形态和一些特性的方式设计，壁虎的刚毛。在我们的实验室中建立了生产它们的合成方法和以高度集成的方式排列它们的路线。两个主要的研究领域，(i)昆虫和壁虎毛附着装置的生物超微结构和力学性能研究，以及（ii）排列有序的碳纳米管的合成、结构、进一步的化学改性和与粘合和摩擦性能相关的实验强度研究是联合研究的重点。碳纳米管表面将通过各种力测量技术进行实验测试，并将数据与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概述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碳纳米管结构在其层次长度尺度上的基本材料特性有新的见解。这些研究必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。计划合作项目的基本成果可能对操纵亚微米零件或器件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、毛发长宽比、坡度、层次、接触的形状、毛发设计的不对称以及在附着和分离过程中的适当运动、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表面结构的人工材料基础时，这些参数大多可以改变。这种结构对干粘合感兴趣，可用于可逆粘合，或在技术重要领域用于安装或操纵微结构甚至纳米结构片的拾取和放置技术。到目前为止，这一仿生学领域几乎没有被触及。

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.