Monolithic Nanofabrication: A Bottom-up Approach for Manufacturing Nanotextured Surfaces

纳米纤维技术通常依赖于加成法或减成法以获得纳米结构化的基底。增材制造涉及通过直接书写或打印数字设计的物体来构建三维物体。减法制造使用蚀刻和其他工艺从批量样品中去除固体材料。然而，将这些方法扩展到纳米级和以高通量方式是具有挑战性的。这个奖项支持一个完全不同的战略，表面纹理在纳米尺度？单片纳米纤维？通过首先用等离子体气体在热聚合物上形成薄层，然后释放系统中的应变。由于表面纳米纹理在压缩时在整个表面上自发形成，因此该技术是大规模并行的。单片纳米纤维的主要优点包括简单性和可扩展性，特别是因为聚合物衬底（没有纳米纤维）已经在收缩包装总线上使用。功能材料中的大面积、分层纳米纹理在一系列应用中是重要的，包括自清洁窗户、水收集、光生物学、生物污染以及减少摩擦和阻力。这项研究是多学科的，涉及制造，机械，化学和材料科学的学科。单片纳米织物的产品将被集成在nanopatterning模块为高中学生在美国国家科学基金会材料世界网络的框架内，在动手活动的公共宣传活动的nanomanufacturing，并在新生化学实验室的聚合物和表面疏水性。单片纳米织物的发展将开辟新的方法来控制无序在纳米尺度和微米尺度。大多数大面积纳米图案化方法旨在以更小的长度尺度产生周期性结构。然而，对于越来越多的应用，有序模式通常不是必需的。这项工作的目的是操纵本地和远程纳米级的障碍，同时在一个单一的基板，从而使层次的纳米纹理，从而使非常规的应用。该项目的主要纳米制造工艺成果是：（1）确定观察纳米折叠和自相似褶皱形成的参数;以及（2）演示热塑性塑料的全化学处理如何生成有序和无序纳米颗粒的可调混合物。主要产品成果包括：（1）具有三个或更多皱纹波长的面内纳米纹理的衬底;（2）控制有序和无序区域的纳米纹理衬底;以及（3）功能材料中的分层纳米纹理。该平台非常适合提取等离子体气体如何与软材料反应以产生局部纳米颗粒的基本原理。自发纹理化过程的可扩展性和热塑性塑料的商业可用性使得单片纳米纤维成为实用的纳米制造策略。

Nanofabrication techniques typically rely on additive or subtractive methods in order to achieve nanostructured substrates. Additive manufacturing involves the building up of a three-dimensional object by direct-writing or printing of a digitally designed object. Subtractive manufacturing uses etching and other processes to remove solid material from a bulk sample. However, extension of these approaches to the nanoscale and in a high-throughput manner is challenging. This award supports an entirely different strategy for surface texturing at the nanoscale?monolithic nanofabrication?by first creating a thin layer on a thermo-polymer with plasma gases and then relieving the strain in the system. Since surface nanotextures form spontaneously across the entire surface upon compression, the technique is massively parallel. Key advantages of monolithic nanofabrication include simplicity and scalability especially since the polymer substrates (without nanopatterns) are already in use on shrink-wrapped buses. Large-area, hierarchical nanotextures in functional materials are important in a range of applications, including self-cleaning windows, water collection, photovoltaics, bio-fouling, and reduced friction and drag. This research is multi-disciplinary and involves the disciplines of manufacturing, mechanics, chemistry, and materials science. Products of monolithic nanofabrication will be integrated in nanopatterning modules for high school students within the NSF Materials World Network framework, in hands-on activities for public outreach events on nanomanufacturing, and in freshmen chemistry labs on polymers and surface hydrophobicity.The development of monolithic nanofabrication will open new approaches to control disorder at the nanoscale and the microscale. Most large-area nanopatterning methods aim to produce periodic structures at ever smaller length scales. Well-ordered patterns are often not necessary, however, for an increasing range of applications. This work aims to manipulate local and long-range nanoscale disorder simultaneously on a single substrate thus making hierarchical nanotextures and hence enable unconventional applications. The major nanomanufacturing processing outcomes of this project are: (1) determining parameters to observe nano-fold and self-similar wrinkle formation; and (2) demonstrating how an all-chemical treatment of thermoplastics can generate a tunable mix of ordered and disordered nanopatterns. The major product outcomes include: (1) substrates with in-plane nanotextures with three or more wrinkle wavelengths; (2) nanotextured substrates with control over ordered and disordered regions; and (3) hierarchical nanotextures in functional materials. This platform is well-suited to extract the fundamental principles of how plasma gases react with soft materials to produce local nano-wrinkling. The scalability of the spontaneous texturing process and commercial availability of thermoplastics make monolithic nanofabrication a practical nanomanufacturing strategy.