Multi-Scale Self-Assembly of Nanotube Structures

碳纳米管（CNTs）和石墨烯等碳纳米材料正在进入一个令人着迷的时代，它们的物理性质和合成方法已经被很好地了解，足以吸引工业界的兴趣。后者最好用碳纳米管的生产能力来量化，碳纳米管的生产能力呈指数级增长，目前已达到每年几千吨。碳纳米管增强复合材料和电池电极等应用推动了这些材料的成功。虽然令人印象深刻，但这些产品通常由碳纳米管的随机混合物组成，其整体性能与在单个纳米管中观察到的相比是有限的。在某种程度上，这是因为今天的碳纳米管产品是用传统的制造能力加工的，比如注塑和喷涂。不幸的是，这些工艺不能对纳米颗粒的排列进行任何结构控制，导致材料性能有限。未来新型纳米碳应用的商业成功将在很大程度上取决于我们设计纳米颗粒组装的能力。在EPSRC的第一笔资助中，我们假设理解碳纳米管之间的物理和化学相互作用是新材料结构自组装的基础，其性能优于随机混合物。更准确地说，我们的目标是开发一种有条理的分层制造方法，在纳米尺度、微观尺度和宏观尺度上系统地优化纳米颗粒组织。为了使这个过程成功，我们将首先寻求对碳纳米管之间粒子间力的物理和化学的理解。然后，利用这些粒子间相互作用作为驱动力的自组装过程将得到优化。更准确地说，该项目建立在PI先前开发的自上而下的光刻工艺基础上，并辅以一种新的自下而上的自组装方法，可以在大型基板上定义良好的纳米颗粒组织。我们设想，在这个项目中开发的材料将特别有趣的各种扩散限制过程。这些应用包括电池电极、水过滤器和催化，在这些应用中，设备的性能受到某些组件在所开发材料中快速扩散的能力的限制。例如，在电池中可以是锂离子，在过滤器中可以是水。该项目开发的工艺的独特之处在于，它允许大规模制造碳纳米管组件，并具有对纳米级形貌和微尺度孔隙率的特殊控制，这是设计扩散路径的关键。虽然对电池应用的深入研究超出了本项目的范围，但我们将进行初步实验以评估所开发材料的性能。

Carbon nanomaterials such as carbon nanotubes (CNTs), and graphene are entering a fascinating era where their physical properties and synthesis methods are understood well enough to attract industry's interest. The latter is best quantified by the production capacity of CNTs, which is increasing exponentially, and has now reached several thousand tons per year. The success of these materials is fueled by applications including CNT-reinforced composites, and battery electrodes. While impressive, these products typically comprise random mixtures of CNTs whose overall properties are limited compared to what is observed in the constituent individual nanotubes. In part, this is because today's CNT products are processed with traditional manufacturing capabilities, such as injection molding and spray coating. Unfortunately these processes do not enable any structural control over the nanoparticle arrangement, resulting in limited material properties. Future commercial success of new nanocarbon applications will largely depend on our ability to engineer the organization of nanoparticle assemblies. In this EPSRC first grant, we hypothesize that understanding of physical and chemical interactions between CNTs underlies the self-assembly of new material architectures with properties superior to random mixtures. More precisely, we aim at developing a methodical hierarchical manufacturing approach where nanoparticle organization is systematically optimized at nanoscale, microscale and macroscale dimensions. For this process to be successful we will first seek understanding of the physics and chemistry of inter-particle forces between CNTs. A self-assembly process will then be optimized which uses these inter-particle interactions as a driving force. More precisely, this project builds on a top-down lithographic process previously developed by the PI, and complements this with a new bottom-up self-assembly approach enabling well-defined nanoparticle organization over large substrates. We envision that the materials developed in this project will be particularly interesting for a variety of diffusion limited processes. These are applications such as battery electrodes, water filters, and catalysis, where the performance of the device is limited by the ability of certain components to diffuse rapidely through the developed material. This can for instance be Li ions in the case of batteries, or water in the case of filters. Unique to the process developed in this project is that it allows for large scale fabrication of CNT assemblies with exceptional control of nanoscale morphology, and micorscale porosity, which is key to engineer the diffusion path. While in depth investigation of for instance battery applications is outside the scope of this project, we will perform preliminary experiments to assess the performance of the developed materials.