Collaborative Research: A Scalable Processing Method to Produce Thermoplastic Nanofibers from Melt

聚合物纳米纤维可以在许多应用中产生重大的社会影响，包括水过滤、药物输送、能量储存以及汽车和航空航天部门的轻质复合材料。尽管有重要的潜在应用，但可扩展的方法生产纳米纤维仍处于初级阶段。目前的方法，如众所周知的电纺工艺，通常依赖于从溶液中进行聚合物加工，在这种溶液中，大量的溶剂被释放到环境中。该溶剂大大增加了原材料成本和生产单位的环境足迹，并要求采取极端的安全通风措施来保护劳动力。该奖项支持基础研究，以产生以无溶剂和工业可扩展的方法生产聚合物纳米纤维所需的知识。该方法适用于多种聚合物。这项研究的结果将影响先进的制造业，从而影响美国经济，因为它建立了无溶剂、因此是“绿色”的纳米纤维生产方法。研究目标的实现将通过多学科的努力，在材料科学、化学工程、纤维加工和能量-物质耦合方面的专业知识的指导下进行。这一努力还将扩大代表不足的学生群体在STEM领域的参与。其目标是发展以环境可持续和可扩展的方式制造连续聚合物纳米纤维的科学和技术。为此，计划设计一种新型的熔体电纺，通过电磁辐射给聚合物熔体提供能量，并通过静电场拉动聚合物熔体。含有碳纳米管夹杂物的超细纤维将被用作纳米纤维的前驱体。这项工作的学术意义部分在于试图对发展纳米纤维所需的能量与物质的耦合产生新的理解。利用超细纤维的提议在智力上也具有重要意义，是可扩展性的关键。微纤维中的纳米管将作为辐射的能量吸收者，提高喷嘴的温度，调节其粘度，并通过静电力帮助缩小喷嘴的直径。研究小组将从实验上研究复合纤维对微波辐射的能量吸收。然后，该团队将开发基于物理的模型，以探索从微纤维形成纳米纤维的过程。根据模型输出，该团队将开发处理纳米纤维的装置。该装置将允许实时监测纳米纤维的形成，以获得对能量-物质耦合的更多洞察。

Polymeric nanofibers can have major societal impacts in many applications including water filtration, drug delivery, energy storage, and light-weight composites for automotive and aerospace sectors. Despite significant potential applications, scalable methods to produce nanofibers are in their infancy. Current methods such as the well-known electrospinning process often rely on polymer processing from solutions in which a large quantity of solvent is released to the environment. The solvent significantly increases the cost of raw materials and the environmental footprint of the production units, and demands extreme measures for safe ventilation to protect the workforce. This award supports fundamental research to generate the knowledge required to produce polymeric nanofibers in a solvent-free and industrially scalable method. The method is applicable to a wide range of polymers. The results from this research will impact advanced manufacturing and, hence, the U.S. economy, by establishing solvent-free and thus "green" nanofiber production methods. The fulfillment of the research goal will be through a multidisciplinary effort, guided by expertise in material science, chemical engineering, fiber processing and energy-matter coupling. This effort will also broaden the participation of underrepresented student groups in STEM fields. The goal is to develop the science and technology of manufacturing continuous polymeric nanofibers in an environmentally sustainable and scalable fashion. To this end, a novel form of melt electrospinning, where polymer melts are energized via electromagnetic radiation and pulled by electrostatic fields, is planned. Microfibers with carbon nanotube inclusions will be utilized as nanofiber precursors. The intellectual significance of this work partly lies in attempts to develop new understanding for coupling energy to matter required to develop nanofibers. The proposition to utilize microfibers is also intellectually significant and is a key to scalability. The nanotubes in microfibers will serve as energy absorbers from radiation to raise the temperature of the jet, regulate its viscosity and assist with reducing the jet diameter via electrostatic forces. The research team will experimentally study the energy absorption by composite fibers from microwave radiation. The team will then develop physics-based models to explore the formation of nanofibers from microfibers. Based on model output, the team will develop the setup to process nanofibers. The setup will allow for real time monitoring of the nanofiber formation to obtain more insight into energy-matter couplings.