In this project, funded by the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professors Chaitanya Ullal and Edmund F. Palermo at Rensselaer Polytechnic Institute are using visible light to precisely direct the synthesis of large nanostructures. The synthesis method utilizes a combination of several different light-based techniques and is reminiscent of classical photography, with the exception that it does not require a projected image using a photomask. The approach can create extremely small patterns, down to a few tens of nanometers in size. Precise control of the shape and size of the objects it creates is also provided. Additionally, patterns can be printed over an entire surface cost-effectively. Research associated with this award has the potential to enable super-resolution printing in 3D without the need to utilize expensive state-of-the art equipment. The new techniques could advance the design of biomedical devices and other advanced manufacturing applictions. The research team is continuing their commitment to education and community outreach, with a particular emphasis on promoting women and under-represented minorities in science through innovative family-based learning activities and design projects. The educational broader impacts include the creation of hands-on learning activities, the development of educational videos, and the mentorship of K-12 students, all of which inspire and promote participation of under-represented students in STEM fields.
The central goal of this research is to create 3D bicontinuous nanostructured materials using a combination of functional macromolecular chemistries and advanced optics, especially super-resolution optics and interference lithography. In the first objective, a deeper fundamental understanding of the underlying chemical kinetics needed to enable super-resolution 3D interference lithography is developed. A library of spirothiopyran derivatives with systematically varied structural features is synthesized in order to precisely tune the kinetics of photo-switching and click reactions leading to a cross-linked polymer gel or thermoset. The second objective focuses on the development of a self-consistent computational model that captures the coupled interaction of the three dimensionally varying light and chemical concentration fields as a function of time. Self-consistent solution of differential equations results in an electromagnetic simulation at each time step of the chemical concentration evolution; This is a departure from conventional finite-element (FEA) or finite-difference time-domain (FDTD) techniques (prohibitively long computation times). The last objective concentrates on bicontinuous super-resolution nanostructures in which the configuration of 3D super-resolution interference lithography consists of a uniform excitation exposure and a depletion pattern that is obtained by the interference of multiple beams of coherent light. Control over the formation of nanostructured materials using unmasked light, with precision over large areas, has a potential to advance the development of photonic crystals, microtrusses and biomedical devices.
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.
