Anisotropic nanostructured materials based on graphene and 2D materials

热管理和散热是一个迅速发展的研究领域。电子产品在我们的日常生活中无处不在。更快、更小的电子设备需要将分布在密度不断增长的芯片上的几个电子元件小型化(截至目前，大约500平方毫米的芯片中有超过7x109个晶体管)。电子器件产生的热量随着同一芯片上电子器件的密度成倍增加。各向异性导热材料能够在一个或两个面内空间方向散热，同时阻止面外方向的导热，是在不影响周围设备的情况下有效散热的理想材料。电子芯片产生的热量的散热有两种主要技术：1)具有高度暴露的表面的散热器，以最大限度地提高芯片顶面的散热效率；2)高度导热的粘合剂糊剂，以散热芯片底部产生的热量。后者依赖于能够快速高效地散热的高效材料。如果石墨烯和杂化二维材料能够以较高的浓度掺入浆料和复合材料中，这将导致高导电性和导热性的浆料和复合材料。此外，将石墨烯纤维聚合物复合材料与通过溶液处理大量生产的其他二维材料(如具有导热和电绝缘的六方氮化硼)相结合，将允许在保持高导热系数的同时调节电学性能。这将导致一类新的电绝缘和导热的浆料和聚合物复合材料，以及高度各向异性的聚合物复合材料和浆料。采用石墨烯或2D材料的各向异性器件很难大规模制造。此外，电和热性能的定制通常需要化学/物理功能化或2D薄片的定向排列，这是通过超分子方法实现的。这些过程通常很难放大。一个潜在的解决方案是将更多的此类二维材料工程到聚合物的结构中，以创建纳米结构复合材料。尤其是各向异性材料可以使用大面积沉积技术来沉积或印刷。因此，将聚合物的可调谐特性和加工性与2D材料的特殊特性相结合的能力可能会使一类新材料的大规模实现。考虑到这一点，该项目的目标是设计和生产具有各向异性特性(例如，热/导电性/绝缘性的管理)的新型聚合物复合材料、浆料和油墨，这些材料可以使用现代和工业相关的沉积技术，如挤出、注塑和3D打印来生产。还有机会研究将二维材料引入天然聚合物中，例如用于电子纺织品的纤维素，以实现成本效益高、易于回收和生物兼容的复合材料，这些复合材料可能被引入服装中。从工程部战略主题的角度来看，该项目旨在促进工程材料的制造、设计和理解。具体地说，这包括纳米级生产和微米级制造以及材料和设备的表征，这显然与该部门的研究雄心相一致。就EPSRC指定的研究领域而言，该项目将为碳和石墨烯技术、复合材料和聚合物材料的发展做出贡献，因为该项目的重点是发展2D材料与聚合物复合材料的集成。

Thermal management and heat dissipation is a rapidly growing research area. Electronics are ubiquitous in our everyday life. Faster and smaller electronic devices require the miniaturisation of several electronic components distributed on chips with ever-growing density (as of today more than 7 x 109 transistors in about 500 mm2). The heat generated by electronic devices increases exponentially with the density of electronic devices on the same chip. Anisotropic thermally conductive materials able to dissipate heat in one or two in-plane spatial directions while barring conductivity in the out-of-plane direction are ideal materials to dissipate heat effectively without affecting surrounding devices.Two main techniques exist for the dissipation of the heat generated by an electronic chip: 1) radiators with highly exposed surfaces to maximize efficient heat dissipation from the top surface of the chip, and 2) highly thermally conductive adhesive pastes to dissipate the heat generated at the bottom of the chip. The latter relies on efficient materials that can rapidly and efficiently dissipate this heat.If graphene and hybrid two-dimensional materials could be incorporated into pastes and composites with a high concentration, this could lead to highly electrically and thermally conductive pastes and composites. Moreover a combination of graphene fibre polymer composites with other two-dimensional materials (such as hexagonal boron nitride which is thermally conducting and electrically insulating) produced in large quantities by solution processing will allow the tuning of electrical properties while retaining high thermal conductivity. This can lead to a new family of electrically insulating and thermally conducting pastes and polymer composites as well as highly anisotropic polymer composites and pastes.Anisotropic devices with graphene or 2D materials are hard to mass manufacture. Moreover, tailoring of the electrical and thermal properties often requires chemical/physical functionalisation or directional alignment of the 2D flakes which is achieved by a supramolecular approach. These processes are generally difficult to scale-up.A potential solution is to engineer more accessible amounts of these 2-D materials into the structures of polymers to create nanostructured composites. Anisotropic materials in particular can be deposited or printed using large area deposition techniques. Hence, the ability to combine the tunable properties and processability of polymers with the exceptional properties of 2-D materials may allow the large-scale realisation of a new class of materials.With this in mind, the aim of this project is to devise and produce a new family of polymer composites, pastes and inks with anisotropic properties (e.g. the management of thermal/electrical conductivity/insulation) that can be produced using modern and industrially-relevant deposition techniques, such as extrusion, injection moulding and 3-D printing. There is also the opportunity to investigate the introduction of 2-D materials into natural polymers, such as cellulose, for electronic textiles to enable cost-effective, easily-recyclable and biocompatible composites that may be introduced into clothing, for instance.From the perspective of the Department of Engineering's strategic themes, this project aims to advance the manufacturing, design and understanding of engineering materials. Specifically, this includes the nanoscale production and microscale fabrication and characterisation of materials and devices, which are clearly aligned with the department's research ambitions. In terms of the EPSRC's designated research areas, this project will contribute to the development of carbon and graphene technology, composite materials and polymer materials, given its focus on developing the integration of 2D materials into polymer composites.