具有梯度弹性模量的仿生微纳米柱状阵列的粘附性能研究

Many animals have the ability to stand and to walk on vertical surfaces and even on ceilings, which is the result of the reversible adhesion generated between micro- and nanostructures on their foot (setae) and counterpart surfaces. It has been found that the fine structures of setae dominating the surface chemistry control the reversible adhesion; therefore, bio-inspired adhesive surfaces could be used in various applications. Inspired by the structure of beetle’s seta, a series of micro-, nano- and hierarchical pillar arrays with gradient elastic modulus along the pillar axis will be designed and constructed by combining different techniques. Parameters for the fabrication of different systems, like polymers used, solvents, external field, environment parameters, et al., will be studied in detail, aiming to reveal the mechanisms of the formation of elastic-modulus gradient. Nanoindentation will be employed to study the relationship between the local structure on pillars and the local elastic modulus. Thorough study will be carefully carried out to investigate the influence of morphology, size and gradient ratio of the gradient structures in micro- and nano-pillar arrays on the contact mechanics and adhesion performances. Comparing to current studies, we will design and study bio-inspired dry adhesives from a new and unique viewpoint, which may become a promising candidate for reversible adhesive with excellent adhesion performances.

很多动物能够在墙壁甚至天花板上站立和自由移动，这是因为它们脚上的有序微纳米结构（刚毛）与接触表面形成了可逆粘附力。可逆粘附力主要由刚毛的结构而非表面化学性质决定。仿生粘附表面因而具有非常广阔的应用前景。受甲虫刚毛结构的启发，本课题拟综合使用多种技术，开发微米级、纳米级和微纳米复合的、在轴向具有弹性模量梯度变化的柱状阵列结构。研究不同体系制备过程中各种参数，如：聚合物、溶剂、外场、加工环境等，对弹性模量梯度形成的影响，以揭示弹性模量梯度的形成机理；利用纳米压痕仪研究局部结构和弹性模量之间的关系；进一步探索梯度结构的形态、尺寸、梯度变化率等对微米、纳米柱阵列在不同表面的接触机理以及对干态粘附性能的影响规律。与现有的研究相比，我们从一个全新的视角来设计、研究仿生干态粘附表面，有望为制备具有良好性能的可逆粘附材料提供一种新的有效途径。

很多动物能够在墙壁甚至天花板上站立和自由移动，这是因为它们脚上的微纳米柱状阵列结构与接触表面形成了可逆黏附力。可逆黏附力主要由微纳米柱状阵列的结构而非表面化学性质决定，仿生黏附表面因而具有非常广阔的应用前景。受甲虫刚毛梯度性质的启发，本项目采用嵌段共聚物选择性溶胀技术、温度梯度场控制光聚合以及离心分散技术，制备得到了微、纳米梯度结构。在不同体系制备过程中，通过调节各种参数，实现了对梯度结构的可控调节，并探讨了梯度结构的形成机制。与柱状阵列结构耦合，制备得到结构稳定的在柱子长轴方向具有梯度弹性模量的微纳米柱状阵列结构。通过结构设计，实现了仿生梯度柱状阵列接触界面的应力调控，进而实现了仿生结构黏附性能的大幅度提升。该项目的成果有望为仿生结构黏附的材料设计提供一种新思路。