Collaborative Research: Manufacturing of Polymer Nanofiber Arrays on Surfaces by Chemical Vapor Deposition into Liquid Crystal Templates

这项研究资助为一种具有变革性的新制造工艺建立知识，这种工艺有可能使一系列美国工业受益，创造新的就业机会和经济活动。电子产品、食品包装和医疗设备的制造商目前使用化学气相沉积的方法，在他们的产品上涂上塑料薄膜，起到保护屏障的作用。这项研究资助的研究人员发现了一种新方法，可以极大地扩展化学气相沉积在制造业中的潜在用途，使用该工艺制造末端附着塑料纳米纤维阵列覆盖的表面。用纳米纤维地毯装饰的表面显示出与连续涂层截然不同的特性，例如提供可调的光学或粘合特性，这些特性可能用于节能和柔性显示器或下一代机器人。该奖项支持基础研究，以了解这些纳米纤维薄膜是如何形成的，以及它们的表面是如何编码的，这些特性对电子、食品和医疗设备行业有用。在这项研究中取得的进展有可能迅速扩大到工业实践的纳米技术，带来经济繁荣和安全。该基金还为下一代制造业劳动力的多学科培训提供了绝佳的机会。在这项资助中要研究的方法包括化学气相沉积成液晶薄膜的聚合物。具体来说，在涂有微米厚液晶膜的表面上进行的化学气相聚合导致末端附着的聚合物纳米纤维形成有组织的组装，具有前所未有的对组织、尺寸（长度和宽度）、表面化学、手性和形状（直、弯或螺旋）的控制。与传统的液晶模板聚合相比，液晶相中的单体浓度仍然很低，因为单体是在气相中形成的，然后扩散到液晶模板中。因此，化学气相聚合可以最大限度地减少单体引起的液晶相行为变化，并可以获得具有精确定义结构的纳米纤维阵列。鉴于可用作化学气相聚合模板的液晶种类繁多，该项目有可能为具有复杂界面形态和化学性质的定向纳米纤维阵列的大规模制造提供一种范式转换方法。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。

This research grant establishes knowledge for a transformative new manufacturing process that has the potential to benefit a range of U.S. industries, creating new jobs and economic activity. Manufacturers of electronics, food packaging and medical devices currently coat their products with thin films of plastics that function as protective barriers using a process called chemical vapor deposition. The investigators supported by this research grant have discovered a new way to greatly expand the potential usefulness of chemical vapor deposition in manufacturing, using the process to fabricate surfaces covered with arrays of end-attached plastic nanofibers. Surfaces decorated with carpets of nanofibers exhibit properties that differ dramatically from continuous coatings, such as providing tunable optical or adhesive properties that might be used in energy-efficient and flexible displays or next generation robotics. This award supports fundamental research needed to understand how these nanofiber films form and how their surfaces are encoded with properties useful for electronics, food and medical device industries. The advances achieved during this research have the potential to be rapidly scaled into an industrially practiced nanotechnology, bringing economic prosperity and security. The grant also provides an outstanding opportunity for multidisciplinary training of the next generation manufacturing workforce.The approach to be investigated in this grant involves chemical vapor deposition of polymers into thin films of liquid crystals. Specifically, chemical vapor polymerization performed on surfaces coated with micrometer-thick films of liquid crystals leads to formation of organized assemblies of end-attached polymer nanofibers with unprecedented control over organization, size (length and width), surface chemistry, chirality, and shape (straight, bent or helical). In contrast to conventional liquid crystal-templated polymerizations, the monomer concentration in the liquid crystal phase remains low, as the monomers are formed in the vapor phase and then diffuse into the liquid crystal template. Accordingly, chemical vapor polymerization minimizes monomer-induced changes to the liquid crystal phase behavior and enables access to nanofiber arrays with precisely defined structures. Given the diverse range of liquid crystals available for use as templates for chemical vapor polymerization, this project has the potential to provide a paradigm-shifting approach for large-scale manufacturing of oriented nanofiber arrays with complex interfacial morphologies and chemistries.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.