Collaborative Research: Understanding UV Protective Mechanisms Using Hybrid Nanoarchitectures

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CBET-0756600TripathiThe central hypothesis of the proposal is that the interactions, at different length scales, between a bioderived active species and various components of a protective nanoarchitecture can lead to significantly increased stability of the active species to UV exposure and oxygen. New hybrid architectures, incorporating synthetic polymers, nanoparticles, and natural dyes or DNA, must be explored to achieve tunable functional properties and to elucidate the relationship between the spatial distribution of protectant molecules (UV absorbers and UV stabilizers) and stabilization efficiency, in the context of the distance and time scales of molecular reorientation and photochemical and diffusive processes. While encapsulation techniques may have shown increases in the thermal and photo-oxidative stability of a UV sensitive material, their use in practical applications is nonexistent due to small gains. Here, we propose a new paradigm for designing protectant materials. To accomplish this objective, we propose development of three novel architectures for protectant materials. Furthermore, we propose a synergistic approach that leverages the strengths of all four PI's by combining experiments and modeling to develop a clear understanding of the mechanism by which polymeric encapsulation improves the photostability of ultraviolet (UV) sensitive materials. Intellectual Merit: The intellectual merit of the program is manifested in the goals of the project that include: (1) Development of core-shell microspheres with tunable protection properties including shell composition and thickness and degree of nanoencapsulation. The design of a new set of modular nanoarchitectures highlights the spatial arrangement of protectant molecules which can be systematically varied and the inhibition efficiency which can be monitored. (2) Development of a controlled microfluidic fabrication method where UV absorbers are integrated into the shell. (3) Novel synthesis routes for the precise production of unique nanoarchitectures encapsulating two complementary active agents: UV sensitive species and UV absorbing substances. (4) Development of transport and molecular modeling to analyze experimental results and to predict the spatial dependence of stabilization for combinations of photostabilizers. The development of synthesis routes and identification of the critical properties for efficient UV protection will help to clarify the interplay of UV protective interactions at various length scales, ranging from the molecular scale to the microscale. This research can guide the development of multifunctional protective materials into future photochemical and environmental technology in the areas of UV protection of sensitive equipment, storage and transport systems for UV sensitive reagents (e.g. biosensing reagents), thereby extending the operational life time of biological and chemical decontamination and protection technologies by preserving molecular structure and therefore function. The research is aimed at understanding how to obtain several advantageous design properties simultaneously, compared with conventional materials, such as transparency with UV-protection, control of oxygen permeation, increased thermal stability, & mechanical integrity. Integrating the outreach programs of several institutions, the proposed collaboration plans to use the experimental methods and outcomes of research as powerful educational tools for graduate, undergraduate and high school students. We propose to develop an educational program that demonstrates key features of reactive processing, nanotechnology, polymer science, and microfluidics for high school and undergraduate students, with the goal of raising and maintaining their interest in science and engineering. Also, we will integrate this research into a semester-long course and a short course for graduate students and participants from local industries. The project will utilize the research expertise of chemists and chemical engineers from Columbia University, Brown University, the University of Massachusetts at Dartmouth, and the U.S. Army Natick Research Center.