Lithographic Patterning of Co-Dispersed Nanomaterials for Device Applications

在柔性或刚性基底上制造成纳米级图案阵列的混合无机纳米颗粒-聚合物基复合材料提供了广泛的新颖光学和电子特性。新的设备可以通过中等规模的特征来创建，其中可以访问和控制分子和本体行为之间的过渡属性。为了实现这种杂化材料的纳米制造，需要开发低成本、灵活、简单和可扩展的方法，以有效地将无机和有机物质组织成大量具有不同功能的特征。自组装很容易形成缺陷，而基于探针和电子束的光刻技术对于大规模生产来说通常太慢。该奖项研究了一种广泛适用的纳米压印光刻工艺，用于对纳米粒子-聚合物混合复合材料进行图案化，并使用它们来制造纳米级光学和电子设备。这是通过使用分散在有机溶剂中的纳米颗粒来实现的，这些纳米颗粒可以快速填充纳米压印聚合物模具，然后固结以形成具有高纳米颗粒负载的图案特征。该项目为研究生和本科生提供培训。计划在弗吉尼亚理工大学校园和西弗吉尼亚科学博物馆夏令营开展几项外展活动，以增加工程领域女性和少数族裔的入学人数。纳米压印光刻可以大规模地以高保真度和可重复性转移纳米级图案。然而，大多数研究都集中在纯聚合物材料系统上。该项目通过解决纳米颗粒和聚合物（单体）在有机溶剂中共分散的关键科学挑战，并利用分散溶剂的蒸发性质以及聚合物链从分散和可溶状态到固态的转变将纳米颗粒和聚合物共悬浮液图案化为纳米级特征，探索用于纳米颗粒-聚合物混合图案化的纳米压印光刻。该研究工作充分探索了在聚合物链存在的情况下纳米粒子在有机溶剂中分散的不同方法。对光刻成型过程中纳米颗粒-聚合物共分散和有机溶剂蒸发的理解有望突破新型混合图案形成的界限。与仅使用聚合物材料的传统纳米压印光刻相比，人们期望出现一种具有复杂结构和新颖功能的新型混合材料。混合模式可以为直接设备使用提供广泛的功能安排。通过结合颗粒-溶剂-聚合物和液体-固体领域边界的知识，这具有巨大的科学和应用潜力。

Hybrid inorganic nanoparticle-polymer matrix composite materials that are fabricated into nanoscale pattern arrays on a flexible or rigid substrate offer a wide range of novel optical and electronic properties. New devices can be created from intermediate scale features where transitional properties between molecular and bulk behaviors can be accessed and controlled. To realize nanomanufacturing of such hybrid materials, low-cost, flexible, simple, and scalable methods need to be developed to efficiently organize inorganic and organic species into a large number of features with distinct functions. Self-assembly is prone to defect formation and probe- and e-beam-based lithography techniques are often too slow for mass production. This award investigates a broadly applicable nanoimprint lithography process for patterning nanoparticle-polymer hybrid composite materials and to use them to manufacture nano-scale optical and electronic devices. This is accomplished by using nanoparticles dispersed in organic solvents that can fill nanoimprinted polymer molds quickly and then be consolidated to form patterned features with high nanoparticle loadings. The project provides training to both graduate and undergraduate students. Several outreach activities on the Virginia Tech campus and summer camps at Science Museum of Western Virginia are planned to increase the enrollment of females and minorities in engineering.Nanoimprint lithography can transfer nanoscale patterns with high fidelity and repeatability in large scales. However, most of the research has been focused on pure polymeric material systems. This project explores nanoimprint lithography for nanoparticle-polymer hybrid patterning by addressing the key scientific challenges of nanoparticle and polymer (monomer) co-dispersion in organic solvents and patterning the nanoparticle and polymer co-suspensions into nano-scale features using the evaporative nature of dispersing solvents and the polymer chain transition from dispersed and soluble state to solid state. The research work fully explores different methods of nanoparticle dispersion in organic solvents in the presence of polymeric chains. The understanding of nanoparticle-polymer co-dispersion and organic solvent evaporation during lithographic molding promises to push the boundaries of novel hybrid pattern formation. In contrast to traditional nanoimprint lithography, which uses polymer materials only, a new class of hybrid materials with intricate architectures and novel functionalities is expected. The hybrid patterns can offer a wide range of feature arrangements for direct device uses. This holds great scientific and application potentials by combining the knowledge at the boundaries of the particle-solvent-polymer and liquid-solid domains.