RAPID: Design, Fabrication, and Testing a Prototype of Heatable Face Mask for Preventing Respiratory Diseases Contracted through Airborne

目前，由于美国的COVID-19大流行，个人防护装备，特别是口罩严重短缺。据统计，一名新冠肺炎患者平均每天消耗17个医护人员佩戴的口罩。这一流行病还影响到军事和惩教设施中的人员。新冠肺炎后的预测显示，在感染和死亡人数曲线趋于平缓和下降后很长一段时间内，仍需要口罩。在今后很长一段时间内，在工作场所、购物中心、公共活动中，戴口罩将成为一种新常态。与此同时，由于需求量巨大，口罩价格也在急剧上涨。这个项目的目标是设计和制造一种可加热和可重复使用的口罩原型，这种口罩可以杀死在口罩表面捕获的病毒，从而防止它们进入人体呼吸系统。这是通过高于病毒致死温度的电阻加热来实现的。将使用一种由工程碳纳米材料制成的薄而透气的隔热膜，这种膜是多孔的，可以改造或放置在任何商用面罩的外表面。这种可加热过滤器由便携式电池或手机供电，与面部皮肤隔热。用户佩戴或存放时可通电消毒。具有不同背景的院系、本科生和研究生，以及一些行业，最终都将参与这个项目。该提案的主要目的是制造和测试一种可加热的多孔碳纳米管空气过滤器，该过滤器被整合到市售的N95呼吸器或其他口罩中，适用于处理病原体的医护人员。焦耳加热是由由垂直排列的碳纳米管阵列绘制的几层碳纳米管片组成的薄膜产生的，但是其他碳纳米管片材料如巴基纸也可以使用。多孔碳纳米管加热器表面直接作用温度设计不超过85℃，足以灭活SARS-CoV-2。当戴上加热口罩时，所选的透气绝缘层将把这个温度降低到无害的37°C。这里提出了第二种口罩操作模式，即使用后的防护设备通过加热30秒激活，对储存的口罩进行消毒，以便再次使用。本提案的目标将通过追求以下目标来实现：(a)设计和制造一种透气的碳纳米管加热器，这种加热器具有灵活性，需要低电压，可以通过便携式电池或手机供电；(b)将多孔碳纳米管加热器集成到商用掩膜中；(c)测试空气流速和口罩灭活病毒替代品的有效性，以及佩戴的安全性。这项工作的智力价值体现在将多孔碳纳米管加热器与传统面罩合并，从而将其转化为可重复使用的个人防护装备，这是第一次在这里提出。这种口罩在其他商业面部防护设备中没有替代品。这一提议的更广泛影响体现在发明的口罩的多用途使用上，预计不仅有利于医疗保健提供者，而且有利于接触生物武器的军事人员，以及有利于公众预防导致COVID-19的病毒。具有不同背景的院系、本科生和研究生，以及一些行业，最终都将参与这个项目。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Currently, there is a significant shortage of Personal Protective Equipment, particularly face masks, due to the COVID-19 pandemic in the United States. The statistic shows that one COVID-19 patient consumes on average 17 face masks per day worn by the medical personnel. The pandemic is also affecting personnel in military and correction facilities. The post COVID-19 forecast describes that the face masks will be required long after the infection and death toll curve is flattened and declines. Wearing face masks will become a new norm for a long period of time at workplaces, shopping centers, and public events. Simultaneously, with the huge demand, face mask prices are increasing dramatically. This project is targeting the design and fabrication of a prototype of heatable and reusable face mask that can kill viruses caught on the mask surfaces thus preventing their penetration within the human respiratory system. This is achieved through resistive heating above the virus lethal temperature. A thin and breathable hater film made of engineered carbon nanomaterials will be used, which is porous and can be retrofitted or placed on the outer surface of any commercial face mask. This heatable filter is powered by a portable battery or a cell phone and is thermally insulated from facial skin. The mask can be energized when worn by the user or in storage to disinfect it. Faculties with diverse background as well as undergraduate and graduate students, and eventually some industries, will be involved in this project. The main objective of the proposal is to fabricate and test a heatable and porous carbon nanotube air filter incorporated into a commercially available N95 respirator or other face masks that are suitable for healthcare workers dealing with pathogens. The Joule heating is generated by a thin film consisting of a few layers of carbon nanotube sheet drawn from vertically aligned carbon nanotube arrays, however other carbon nanotube sheet materials like Bucky paper can be also employed. The performance temperature directly on the surface of the porous carbon nanotube heater is designed not to exceed 85 °C, which will be enough to inactivate SARS-CoV-2. The selected breathable insulating layers will attenuate this temperature down to the harmless 37 °C when wearing the heated mask. A second mode of the mask operation is proposed here when the protective equipment after use is activated by heating for 30 seconds which will disinfect the stored mask for reuse. The objective of this proposal will be achieved by pursuing the following aims: (a) design and fabricate a breathable carbon nanotube heater that is flexible and requires low voltage for powering via a portable battery or cell phone; (b) integrate the porous carbon nanotube heater into commercial masks; (c) test the air flow rate and the effectiveness of the mask to inactivate virus surrogates, and its safety to be worn. The intellectual merit of the proposed work is seen in the merging of a porous carbon nanotube heater with a conventional face mask, thus converting it to a reusable Personal Protective Equipment, which is proposed here for the first time. This mask does not have an alternative among other commercial face protective equipment. The broader impact of this proposal can be found in the multipurpose use of the invented face mask, which is expected to be beneficial not only for healthcare providers, but also for military personnel exposed to biological weapons, as well as for the general public preventing viruses causing COVID-19. Faculties with diverse background as well as undergraduate and graduate students, and eventually some industries, will be involved in this project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.