Understanding interfacial gas retention under water: A materials approach using aligned carbon nanotube architectures

植物和动物已经进化了数百万年的高度复杂的层次结构表面，以适应特定的环境条件。一些昆虫、蜘蛛和植物甚至能够在水下保持持久的气体层。这些空气层和不同的支撑结构作为本研究项目中采用的仿生全碳基材料系统的“活角色模型”。该项目的重点是超疏水气体保持垂直排列的碳纳米管（VACNTs）。该合作研究项目旨在探索物理和化学材料的基本原理，使气体在水中和其他溶剂中保持不变。碳纳米管，特别是VACNT已被确立为具有广泛可调的化学和物理性质的有价值的材料，包括它们的排列和化学表面功能化。这种材料的长度、直径、弹性、化学功能都可以定制，提供了各种重要的特性（例如机械强度、pH值、耐腐蚀性和抗结垢性），这种材料的惊人可变性将使人们能够对水下气体保留的基础知识进行广泛的研究。它是独特的，可以作为一个模型结构，以获得更深入的了解界面材料的性质，如物理表面结构和化学表面功能，这两者都是必要的，以获得这样的行为。对气体保持材料领域的材料发展有更深入和全面的了解可能会产生什么一般性影响？了解气体和空气保留在拟议的VACNT模型系统的基本原理将奠定基础，为未来利用水下空气保留表面，在工程和科学的各个领域的应用从减阻或气体交换到传感系统。虽然减阻已经成为工程师和生物学家关注的焦点，但像压力传感和气体交换这样的领域迄今为止只有很少的研究和理解。这可归因于缺乏直接可获得的材料或获得这些材料的复杂技术，或两者兼而有之。随着使用VACNTs作为模型材料，这可以克服和定制的几何（物理）和表面（化学）性质相对于气-水界面将使我们能够解开的因素，支配其气体保留性能。在这个建议，将被解决，以达到这些目标的具体任务是：通过调整其几何参数（直径，距离，高度，倾斜度）和它们的表面化学（通过表面功能化调整疏水性）的VACNTs的物理和化学表面特性的调谐。确定水-气界面相对于尺寸的形状和稳定性、对不同压力条件的稳定性、气体环境的改变、气体交换和溶剂环境。

Plants and animals have evolved over millions of years highly complex hierarchical structured surfaces as an adaptation to particular environmental conditions. Some insects, spiders and plants are even able to maintain persistent gas layers under water. These air layers and the different supporting structures serve as “living role models” for the biomimetic all carbon based material system employed in this research project. The project focusses on super hydrophobic gas retaining vertically aligned carbon nanotubes (VACNTs). The collaborative research project aims to explore the physical and chemical material fundamentals allowing gas retention under water and other solvents. CNTs and especially VACNTs have been established as valuable materials with widely tunable chemical and physical properties including their alignment and chemical surface functionalization. The amazing variability of this material which can be tailored in length, diameter, elasticity, chemical functionality, providing a variety of important properties (e.g. mechanical strength, pH and corrosion and fouling resistivity) will enable extensive studies on the basics of gas retention under water. It is unique and can serve as a model structure to gain deeper insight into the interfacial material properties like physical surface structure and chemical surface functionality which are both necessary to obtain such a behavior. What general impact might a deeper and complete understanding on materials development in the area of gas retention materials have? Understanding the fundamentals of gas and air retention in the proposed VACNT model system will lay the foundation for the future utilization of under water air retaining surfaces which have applications in various fields of engineering and science going from drag reduction or gas exchange to sensory systems. Whereas drag reduction has already been in the focus of engineers and biologists areas like pressure sensing and gas exchange are so far only sparsely studied and understood. This can be attributed to a lack of either straightforward accessible materials or elaborate techniques to obtain those or a combination of both reasons. With the usage of VACNTs as model material this could be overcome and tailoring the geometric (physical) and surface (chemical) properties with respect to the gas-water interface will enable us to unravel the factors which govern their gas retention properties. Specific tasks in this proposal which will be addressed to reach these goals are: Tuning of the physical and chemical surface properties of VACNTs by adjusting their geometrical parameters (diameter, distance, height, inclinement) and their surface chemistry (tuning hydrophobicity by surface functionalization). Determining the shape and stability of the water-gas interface with respect to size, stability towards different pressure conditions modification of the gas environment, exchange of gases and solvent environment.