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.
