Biomimetic Micro/Nano-structured Adhesive Materials with "Smart" Properties

随着对机器小型化和性能密度最大化的需求的快速增长，相似和不同材料部件的有效粘接和/或连接已经成为制造更小规模的生物传感器、医疗设备、微电子和许多其他技术的最关键的技术先决条件之一，其中其他材料连接手段(例如螺栓-螺母、紧固、焊接)不能有效地工作。拟议的研究计划旨在开发具有智能特性的仿生微纳米结构粘接材料，用于下一代先进材料和制造工艺。在当前的发现资助计划中，我的研究团队受到生物系统的优越性能和结构的启发，如莲花超疏水防粘树叶和壁虎粘附性脚趾垫，在当前的发现资助计划中，我的研究团队开发了几代仿生微结构，并使用它们来定制粘合和相关的界面现象，如材料之间的界面润湿、变形和破裂。我们还开发了各种纳米材料，并对聚合物粘合剂的粘弹性行为和纳米级表面相互作用有了深入的了解。在以往成功的基础上，拟议的计划将通过扩大纳米技术和纳米科学的最新进展，进一步发展这一令人兴奋的仿生领域，开发具有多功能“智能”特性的新一代仿生粘合剂。基于我们自己的研究成果和文献报道，我们提出了将功能纳米复合材料用于仿生粘接结构的新概念，导电纳米薄膜之间的相互作用以及它们与聚合物基质的相互作用将使纳米复合仿生粘接结构具有多功能的智能性能。我们的胶粘剂研究在电子制造中的应用已经建立了良好的利基市场。我们将专注于诸如导电性、压电响应和附着力适应等智能。纳米级的功能填充物(如银)将被引入仿生结构中，使其导电，从而向粘合材料提供诸如压电和传感特性等“智能”功能。这些智能仿生结构将通过先进的化学手段进行功能化，使其在具有挑战性的表面具有适应性的粘附性。例如，壁虎对干燥和潮湿的条件都有很好的适应能力；但目前的壁虎模拟动物缺乏这种适应性，限制了它在潮湿条件下的应用。在拟议的项目中，将合成新型水凝胶类薄膜，并将其用于粘接结构的功能化，使其具有所需的适应性粘接性能。与壁虎脚垫上的表面蛋白质类似，表面聚合物凝胶具有对环境条件变化的反应能力。此外，这项研究还将探索如何将已开发的技术和机械知识转化为用于生物和机械系统应用的有效粘合和粘合工艺。总体而言，拟议的研究计划走在了生物材料领域的前沿，并为研究生提供了极好的培训机会。计划中的研究活动具有原创性和创新性，可能会带来革命性的进展，对科学界产生广泛影响。这一计划将有助于保持加拿大科学界和制造业的竞争优势，也将造福人类。

With the rapidly growing demand to miniaturize machines and maximize their performance density, the effective adhesion and/or joining of similar and dissimilar material components has become one of the most critical technical prerequisites for manufacturing biosensors, medical devices, microelectronics and many other technologies at ever-smaller scales, where other means of materials joining (e.g., bolts-nuts, fastening, welding) do not work effectively. The proposed program of research aims at the development of biomimetic micro and nano-structured adhesive materials with smart properties for next-generation advanced materials and manufacturing processes. Inspired by the superior properties and structures of biological systems, such as lotus superhydrophobic anti-adhesive leaves and gecko adhesive toe pads, in the current Discovery Grant program, my research team has developed several generations of biomimetic micro-structures and used them to tailor adhesion and associated interfacial phenomena, such as wetting, deformation, and cracking at interface between materials. We also developed various nanoscale materials and acquired a deep understanding of viscoelastic behavior of polymer adhesives and nanoscale surface interactions. Building on the previous successes, the proposed program will further develop this exciting biomimetic field by extending recent advances in nanotechnology and nanoscience to develop a new generation of biomimetic adhesives with multifunctional "smart" properties. Based on our own research findings and literature reports, we have developed a new concept of using functional nanocomposite materials in the biomimetic adhesive structures; the interplay among the electrically conductive nanofillers and their interaction with the polymer matrix will make the nanocomposite biomimetic adhesive structures possible to deliver multifunctional “smart” properties. A nice niche of application of our adhesive research in electronic manufactures has been established. We will focus on such smartness as electrical conductivity, piezoelectric responses and adhesion adaptation. Nanoscale functional fillers (e.g. silver) will be incorporated into the biomimetic structures to make them electrically conductive so as to deliver such “smart” functions as piezoelectric and sensing properties to adhesive materials. These smart biomimetic structures will be functionalized with advanced chemistry to make it have adaptable adhesion to challenging surfaces. For example, Geckos are well adapted to both dry and wet conditions; but current gecko mimics lack this adaptability and limits its applications in humid and wet conditions. Under the proposed project, new types of hydrogel-like thin films will be synthesized and utilized to functionalize the adhesive structures so that they can have the desired adaptable adhesion properties. Similar to surface proteins on the gecko foot pad, the surface polymer gel have the ability to response to changes in environmental conditions. Furthermore, this research will explore ways to transfer the developed technology and mechanistic understanding into effective adhesion and bonding processes used in biological and mechanical systems’ applications. Overall, the proposed research program is at the forefront of the field of bionanomaterials and provides excellent training opportunities for graduate students. The planned research activities are original and innovative, likely leading to revolutionary advances that will have a broad impact to the scientific community. This program will help maintain the competitive advantage of Canadian scientific community and manufacturing industries and benefit mankind as well.