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

这项研究拨款为一种变革性的新制造工艺建立了知识，这种工艺有可能造福于美国的一系列行业，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在他们的产品上涂上塑料薄膜，这种薄膜使用一种名为化学气相沉积的过程作为保护屏障。在这项研究拨款的支持下，研究人员发现了一种新的方法，可以极大地扩大化学气相沉积在制造业中的潜在用途，使用这种工艺来制造覆盖有端接塑料纳米纤维阵列的表面。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结剂特性，这些特性可能用于节能和柔性显示器或下一代机器人。该奖项支持所需的基础研究，以了解这些纳米纤维膜是如何形成的，以及它们的表面是如何编码的，具有对电子、食品和医疗器械行业有用的特性。在这项研究中取得的进展有可能迅速扩大到工业实践中的纳米技术，带来经济繁荣和安全。这笔赠款还为新一代制造业劳动力的多学科培训提供了一个绝佳的机会。这笔赠款将研究的方法涉及将聚合物化学气相沉积到液晶薄膜中。具体地说，在涂有微米厚的液晶薄膜的表面上进行化学气相聚合，可以形成端接的聚合物纳米纤维的有序组件，对组织、大小(长度和宽度)、表面化学、手性和形状(直、弯或螺旋)进行前所未有的控制。与传统的液晶模板化聚合相比，液晶相中的单体浓度保持较低，因为单体在气相中形成，然后扩散到液晶模板中。因此，化学气相聚合将单体引起的液晶相行为的变化降至最低，并能够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，该项目有可能为大规模制造具有复杂界面形貌和化学成分的定向纳米纤维阵列提供一种范式转换方法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.