Manufacturing Multi-Material Nanostructures Using Supercritical CO2-Assisted Spray Deposition

该补助金支持在纳米结构表面制造方面贡献新知识的研究，促进美国在制造科学和技术方面的进步，并促进国家繁荣。通常通过在所需基底上沉积和图案化纳米材料来制造的纳米结构化表面对于在许多设备中提供诸如结构、电、热、磁、光和音频的功能是必不可少的。有许多制造技术来制造纳米结构表面。然而，几乎所有这些技术都需要昂贵的多步骤工艺来制备纳米材料和表面，可能使用有害溶剂，并且在材料选择方面受到限制。如果在单个应用中需要多种功能，则这些技术通常不能在单个基板上同时沉积多种类型的材料。该补助金支持基础研究，为喷雾沉积制造工艺的开发提供所需的知识，该工艺能够用多种材料可扩展和高精度地制造多功能纳米结构表面，而不需要昂贵的制备或使用有害溶剂。这项研究能够大规模制造尺寸从微米到厘米的结构多功能纳米结构表面，并降低最终成本，应用于功能涂料，可穿戴电子产品，智能纺织品和涂料以及电子设备。这项研究的结果将为美国多个行业提供一种新的可扩展的制造技术，从而使美国经济和社会受益，增加国内就业机会，让更多的公众获得智能技术。这项研究是一项跨学科的工作，涉及加工和制造科学，机械，材料科学和化学，并为美国劳动力培养下一代高技能的工程师和科学家。此外，这项研究将为妇女，代表性不足的少数群体和STEM领域的资深学生提供独特的研究机会。研究结果将有助于K-12学生的教育，通过培训高中教师纳米材料和纳米结构制造，并帮助他们将这些概念融入他们的教育课程。超临界CO2辅助喷雾沉积制造过程可以通过组合不同的纳米材料图案来生成精确图案化的三维多材料纳米结构。这项研究将克服纳米结构表面制造中存在的几个局限性，如颗粒/基材/溶剂的缓慢和昂贵的处理，外部刺激的使用，由于纳米材料和溶剂的相容性而导致的材料选择范围窄，以及小的构建区域。该项目旨在通过产生关于纳米材料图案开发的新知识来克服这些障碍，这些纳米材料图案形成由分子间力控制的表面纳米结构。本研究将解决蒸发液滴中纳米材料与固-液-气界面之间的分子间力平衡的演化，并阐明两亲性和液滴性质对这些力的影响。该研究将实验表征与密度泛函理论和分子动力学模拟相结合，以将特定的分子间力映射到纳米材料图案和所得的纳米结构。该奖项反映了NSF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。

This grant supports research that contributes new knowledge in manufacturing of nanostructured surfaces, promoting both the U.S. progress in manufacturing science and technology and advancing national prosperity. Nanostructured surfaces, often fabricated by depositing and patterning nanomaterials on desired substrates, are essential to provide functionalities such as structural, electrical, thermal, magnetic, optical, and audio in many devices. There are many manufacturing techniques to fabricate nanostructured surfaces. However, almost all these techniques require costly multi-step processes to prepare both nanomaterials and surfaces, could use hazardous solvents and are limited in the choice of materials. If multiple functionalities are required in a single application, these techniques are often incapable of depositing multiple types of materials at once on a single substrate. This grant supports fundamental research to provide needed knowledge for the development of a spray-deposition manufacturing process that enables scalable and high-precision manufacturing of multifunctional nanostructured surfaces with multiple materials without the need for costly preparations or use of hazardous solvents. This research enables manufacturing of structural multifunctional nanostructured surfaces with sizes ranging from micrometer to centimeter at large scale and reduced final costs with applications in functional coatings, wearable electronics, smart textiles and paints, and electronic devices. The results from this research will equip multiple U.S. industries with a new scalable manufacturing technique and thus benefit the U.S. economy and society with increased domestic job opportunities and more public access to smart technology. This research is an interdisciplinary effort that involves processing and manufacturing science, mechanics, materials science, and chemistry and trains the next generation of highly skilled engineers and scientists for the U.S. workforce. In addition, this research will provide unique research opportunities for women, underrepresented minority groups, and veteran students in STEM fields. The research findings will contribute to the education of K-12 students through training high-school teachers on nanomaterials and nanostructure manufacturing and help them integrate these concepts into their educational curriculum.The supercritical CO2-assisted spray-deposition manufacturing process can generate precisely patterned three-dimensional multi-material nanostructures by composing different nanomaterials patterns. This research will overcome several limitations existing in fabrication of nanostructured surfaces such as slow and costly treatment of the particles/substrates/solvent, use of external stimuli, narrow selection of materials due to compatibility of nanomaterials and solvent, and small build areas. This project intends to overcome these barriers by generating new knowledge on the development of nanomaterial patterns that form surface nanostructures controlled by intermolecular forces. This research will resolve the evolution of intermolecular force balance between nanomaterials and solid-liquid-gas interfaces in evaporating droplets and elucidate the effect of amphiphilicity and droplet properties on these forces. The research combines experimental characterization with density functional theory and molecular dynamics simulations to map specific intermolecular forces to nanomaterial patterns and the resultant nanostructures. This knowledge establishes Force-Pattern-Microstructure-Property relationship to transform the researched method into a viable material-agnostic manufacturing technique for fabrication of next generation of structural multifunctional components.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.