NER: Self-Assembled Liquid Crystal Thermoset Nano-Composites with Functionally Graded Properties

这项纳米级探索性研究（NER）项目的目标是建立一种具有功能梯度特性的新型自组装三维纳米复合材料的可行性。该项目将试图确定热固性、反应性液晶（LC）单体（含碳纳米管）使用喷墨打印工艺形成功能性纳米复合材料的原理。复合材料的形成可以适应局部成分的变化。当单体沉积时，它们将被磁场选择性地定向成三维，然后通过原位固化单体来锁定定向。定向含有纳米管的LC分子将导致纳米管的自对准。复合材料将通过激光照射紫外线进行光固化。该研究的目的是合成具有不同模量、强度和韧性值的特定区域的3d复合材料，以提高其整体机械（和热）性能。这项工作将包括选择和组合最合适的聚合物和纳米管组合物，以及确定喷墨加工和固化的最佳条件。这项研究还将为亚利桑那大学的一名研究生在这一新技术领域的参与提供机会。如果成功，LC基质树脂与碳纳米管的结合，如图所示，有望生产出比目前最好的碳纤维环氧复合材料更坚硬、更坚韧（耐损伤）、更耐刮擦的复合材料。许多行业和政府机构都有兴趣采用这种新技术，通过计算机控制的逐级分层沉积直接合成3D复合材料。这种工艺将允许直接生产高性能复合材料，而无需使用传统的铸造、锻造、加工、成型或预浸。此外，随意生产新形状的能力使其能够在各种场所快速，灵活，定制化生产。特别是，它提供了相当大的潜力，未来应用于空间飞行器的外星定制生产复合材料部件。与两个独立的工业组织之间现有的合作安排将促进技术向工业的转让。

The objective of this Nanoscale Exploratory Research (NER) project is to establish the feasibility on a new class of self-assembled, 3-D nano-composites with functionally graded properties. The project will seek to determine the principles behind forming functional nanocomposites from thermosetting, reactive liquid crystal (LC) monomers containing carbon nanotubes using an inkjet printing process. The composites will be formed so that local variations in composition can be accommodated. As the monomers are deposited they will be selectively oriented in 3 dimensions by a magnetic field and the orientation then will be locked-in by curing the monomers in-situ. Orienting LC molecules containing nanotubes will result in self-alignment of the nanotubes. The composites will be photocured by exposure with UV radiation delivered by a laser. The objective of the research will be to synthesize 3D-composites designed with specific regions that have different modulus, strength, and toughness values defined so as to enhance their overall mechanical (and thermal) performance. The work will include selecting and combining the most appropriate polymer and nanotube compositions as well as determining the optimum conditions for inkjet processing and curing. This research also will provide an opportunity for the participation of a graduate student in this new technology area at the University of Arizona.If successful, the combination of an LC matrix resin with carbon nanotubes, as depicted here, is expected to produce composites that are stiffer, tougher (damage tolerant), and more scratch resistant than the currently best available carbon fiber-epoxy composites. Numerous industries and Government agencies are interested in adapting this new technology for the direct synthesis of 3D- composites by computer-controlled step-by step, layered deposition. Such a process will allow the direct production of high-performance composites without the use of conventional casting, forging, machining, molding or prepregging. Further, the ability to produce new shapes at will lends itself to rapid, flexible, customized production in various venues. In particular, it offers considerable potential for future application in space vehicles for extraterrestrial customized production of composite parts. Transfer of the technology to industry will be facilitated by an existing collaborative arrangement with two separate industrial organizations.