CAREER: Dual-Wavelength Sub-diffraction Limited Digital-light Projection (DLP) for High-Performance, Nano-Architected Polymers

This Faculty Early Career Development Program (CAREER) award enables contribution of new knowledge in advancing the state-of-the-art light-based additive manufacturing (AM) for scalable fabrication of high-performance, nanostructured polymeric materials. With the rising need of heterogeneous integration and III-V-on-Si photonic integrated circuits (PICs) in microelectronics industry, 3D nanostructured polymeric materials are playing increasingly important role beyond sacrificial 2D photoresists in pattern transfer. Traditional lithographic approaches fall short in fabricating continuous 3D nano-pathways due to difficulties in repeated molding and etching processes. In contrast, high-resolution additive manufacturing approaches, such as digital-light-projection (DLP) processes, readily create micrometer resolution 3D structures, serving as promising platform candidates. This award supports the establishment of fundamental knowledge that pushes the boundary of low-energy, continuous wavelength DLP that addresses critical challenges in existing patterning resolution-scalability tradeoff, provides direct understanding on in-situ photochemical reactions at nano-resolutions, and develops advanced photosensitive resins with high-performing thermo-mechanical properties. This research program will be integrated with educational and outreach activities, including incorporation of AI-driven model development in material characterization coursework, tutorial YouTube videos for characterization of soft and hybrid materials, and organization of industry career panel involving regional industrial leaders. The research goal of this project is to establish a research program that produces the scientific knowledge for enabling scalable fabrication of nanostructured high-performance polymer materials. To break the nanometer resolution-scalability trade off in low-energy, continuous wavelength digital-light-projection (DLP) platforms, this project will establish a dual-wavelength DLP platform that combines frequency-controlled structured illumination with wavelength-specific photoiniferter chemistry to enable sub-diffraction, area-unlimited printing. To elucidate in-situ reaction kinetics at the nano-resolution that is unachievable via existing infrared microscopy, a mid-infrared pump-probe spectroscopy will be built within the DLP platform. The in-situ IR spectroscopy characterization will also inform the physical model that combines optical and reaction-diffusion kinetics simulations to predict the crosslinking kinetics and inter-wavelength material property evolution. To enable high-performing polymer material patterning that is compatible with nano-resolution DLP platform, a dual-cure, photo- and thermally sensitive resin material will be developed, through utilization of dynamic covalent chemistry that enables the tunability of mechanical and thermal properties. Taken together, the this research aims to establish a new paradigm for fabricating sub-diffraction limited, high-performance polymeric materials, with critical process-relevant reaction kinetics obtained from in-situ microscopy characterization. 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. NSF Award ID: 2542480 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Kaiwen Hsiao | Institution: Texas A&M Engineering Experiment Station, COLLEGE STATION, TX | Award Amount: $550,000 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2542480 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2542480.html