Collaborative Research: Nanoimprinting of High Aspect-Ratio Nanostructures in Thermoplastic Polymers Using Metallic Glass Roller Molds

这个合作研究团队使用多学科方法来研究通过使用金属玻璃辊模具实现热塑性聚合物薄膜表面可伸缩印记的可行性。具有高长径比纳米特征的热塑性聚合物具有多种性能，在太阳能电池、透明导电膜和光子晶体等领域有着广泛的应用前景。使用卷对卷(R2R)纳米压印技术制造具有纳米级特征的此类薄膜是为反应性聚合物开发的，但对热塑性聚合物来说一直是一个挑战，因为它们的粘性通常要高出100倍以上，并且需要显著更高的压印压力。因此，迫切需要开发一种用于热塑性纳米压印的精密且耐用的辊模。这个合作项目涉及两个机构，一个领导热塑性塑料衬底中高纵横比纳米结构的设计和卷对卷制造的研究，另一个指导表征和建模方面的工作。这项研究的结果形成了将新型制造技术成功转移到工业中的科学基础，并使经济地生产用于能源、医疗保健、汽车和电信应用的纳米设备成为可能。该项目进一步丰富了课程开发，特别是在纳米制造的跨学科领域，并扩大了妇女和代表性不足群体对研究的参与。该奖项支持基础研究，以探索一种可行的纳米制造工艺，使用机械坚固的金属玻璃辊模连续生产高保真热塑性纳米结构。金属玻璃是一类高强度金属，可以像塑料一样在过冷的液体状态下被加工成特征尺寸低至10纳米的大型几何形状。这个项目涉及几项任务。(1)研究了平面纳米结构在金属玻璃涂层辊模曲面上的转移。(2)非晶态金属玻璃滚筒纳米压印热机械加工窗口的确定。(3)利用近距离加热来提高复制精度。(4)印迹纳米结构复制保真度的表征。(5)基于卷对卷纳米制造过程的数值模拟性能。关于金属玻璃和热塑性聚合物在连续纳米印迹过程中的纳米尺度动力学，预计将做出基本贡献。特别是，这项研究促进了对(A)纳米级金属玻璃和热塑性聚合物的流变学和加工-微观结构-性能关系的理解，(B)金属玻璃在过冷液体区域的结晶，以及(C)材料的精确控制和优化？S纳米级制造的热机械历史。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 collaborative research team uses a multidisciplinary approach to investigate the feasibility of scalable imprinting of thermoplastic polymer film surfaces enabled by the use of metallic glass roller molds. Thermoplastic polymers with high aspect-ratio nanoscale features exhibit versatile properties and are highly desired in numerous applications such as solar cells, transparent conducting films and photonic crystals. Manufacturing such films with nanoscale features using roll-to-roll (R2R) nanoimprinting has been developed for reactive polymers but has been a challenge for thermoplastic polymers because they are typically over 100 times more viscous and require significantly higher imprinting pressure. Hence, there emerges a need for the development of a precise and durable roller mold for thermoplastic nanoimprinting. This collaborative project involves two institutions, one leading investigations into the design and roll-to-roll manufacture of the high aspect-ratio nanostructures in thermoplastic substrates, the other directing efforts in characterization and modeling. Results from this research forms the scientific basis for successful transfer of the novel manufacturing technology to industry and enables economic production of nanodevices for applications in energy, healthcare, automotive, and telecommunication. The project further enriches curriculum development, particularly in the interdisciplinary area of nanomanufacturing, and broadens the participation of women and underrepresented groups in research. This award supports fundamental research to explore a viable nanomanufacturing process using a mechanically robust metallic glass roller mold for continuous production of high-fidelity thermoplastic nanostructures. Metallic glasses are a class of high strength metals that can be processed like plastics in their supercooled liquid state into large-scale geometries with feature sizes down to 10 nm. The project involves several tasks. (1) Investigations into the transfer of planar nanostructures onto the curved surface of metallic glass coated roller molds. (2) Identification of the thermomechanical processing window for roller nanoimprinting of metallic glasses without crystallization. (3) Utilization of proximity heating to enhance the replication precision. (4) Characterization of the replication fidelity of the imprinted nanostructures. (5) Performance of numerical modeling of roll-to-roll based nanomanufacturing processes. Fundamental contributions are anticipated regarding the nanoscale dynamics of metallic glasses and thermoplastic polymers during continuous nanoimprinting. Particularly, the research advances the understanding of (a) rheology and processing-microstructure-property relations in metallic glasses and thermoplastic polymers at nanoscale, (b) crystallization of metallic glasses in the supercooled liquid regime, and (c) precise control and optimization of material?s thermomechanical history in nanoscale fabrication.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.