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、汽车和航空航天领域的轻质复合材料。尽管有巨大的潜在应用，但生产纳米纤维的可扩展方法仍处于起步阶段。目前的方法，如众所周知的静电纺丝工艺，通常依赖于将大量溶剂释放到环境中的溶液进行聚合物加工。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。这项研究的结果将通过建立无溶剂的“绿色”纳米纤维生产方法，影响先进制造业，从而影响美国经济。在材料科学、化学工程、纤维加工和能量-物质耦合等专业知识的指导下，将通过多学科的努力来实现研究目标。这一努力还将扩大未被充分代表的学生群体在STEM领域的参与。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，计划开发一种新型的熔体静电纺丝，即聚合物熔体通过电磁辐射通电并受到静电场的牵引。含有碳纳米管的微纤维将被用作纳米纤维的前驱体。这项工作的智力意义部分在于试图对开发纳米纤维所需的耦合能和物质建立新的认识。利用微纤维的主张在智力上也很重要，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剂，以提高射流的温度，调节其粘度，并通过静电力帮助减小射流直径。研究小组将对复合纤维吸收微波辐射的能量进行实验研究。然后，该团队将开发基于物理的模型来探索由微纤维形成纳米纤维的过程。基于模型输出，该团队将开发加工纳米纤维的装置。该装置将允许对纳米纤维的形成进行实时监测，从而更深入地了解能量-物质耦合。

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.