SCREENING WAVELENGTH SELECTIVITY OF PHOTOCHEMICAL TRANSFORMATIONS
Abstract
Numerous applications rely on molecular transformations that occur upon exposure to light, including 3D printing, imaging, lithography, coatings, and adhesives. The utility of light to induce a rapid polymerization and solidification (~seconds) of a liquid monomeric resin (termed photocuring) can be tracked through changes in absorption. While photocuring has been dominated by the utility of UV light, visible and near infrared (NIR) light offer attractive benefits, including reduced cost and energy of irradiation from readily available LEDs, improved biocompatibility and functional group tolerance, and greater depth of penetration due in-part to reduced scattering. However, the utility of visible-NIR photocurable resins has been hampered by the general lack of fundamental insight pertaining to how different wavelengths of light correlate to polymerization efficiency. Thus, an approach that enables rapid photopolymerization monitoring in real-time as a function of incident light wavelength and intensity (photon flux) is proposed. To this end, a wavelength tunable laser system is proposed and will be coupled to existing UV-vis and FTIR spectrometers. The acquisition of the proposed instrumentation will greatly accelerate fundamental efforts to discover new visible light photocatalysts and identify structure-property relationships between photocatalyst composition and curing efficiency that will improve the speed and selectivity of photopolymer resins. These advancements will enable high resolution, low energy, and rapid photocuring to prepare next generation ÒsmartÓ plastics with designer mechanical properties (e.g., strong, stiff, tough, and elastic) and applications relevant to the Department of Defense (e.g., soft robotics, data storage, and camouflage). Moreover, seamless compatibility with light-based additive manufacturing approaches (e.g., stereolithography) will facilitate production of customizable 3D objects on-site, such as spare parts to repair or replace broken equipment in the field. The proposed instrumentation will also benefit ongoing projects funded by the Army Research Office and the Air Force Office of Scientific Research aimed at using light to create and manipulate soft materials, including research programs in the Departments of Chemistry and Electrical, Chemical, and Mechanical Engineering at UT Austin. The instrumentation will be centrally located in a photopolymer characterization lab on campus, which will foster interdisciplinary research efforts. Additionally, integration of the proposed system into an existing research-based laboratory course will provide hands-on experience to enhance the infrastructure of (under)graduate student and postdoctoral training at UT Austin.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 15, 2023
- Source ID
- W911NF2310097
Entities
People
- Zachariah A Page
Organizations
- Army Contracting Command
- United States Army
- University of Texas at Austin