Collaborative Research: DMREF: NSF-DST: Accelerated Development of Polymer Salogels

About This Grant

Non-technical Description: Phase change materials (PCMs) absorb, store or release energy when they change from liquid to solid and thus can regulate temperature in personal care products (such as cooling pillows, pads and patches in sporting and biomedical products), as well as for regulation of temperature in buildings. One promising type of phase change materials, inorganic salt hydrates, is inflammable and thermally efficient but suffers from fluidity/leakage during thermal cycling. The challenge is to controllably shape stabilize these materials without sacrificing their thermal performance. This project explores the use of star-shaped block copolymers to control thermomechanical properties of the resulting PCM-polymer composites, i.e. salogels. The team addresses the challenges of polymer solubility and gelation (i.e. formation of a polymer network) in a complex ionic environment of inorganic salt hydrates via the use of material discovery and optimization using modeling, theory and AI/machine learning (ML) in a coordinated US-India team effort. This project provides a knowledge base that will correlate molecular parameters of star polymers and type of inorganic salt hydrates with thermomechanical properties of salogels, enabling accelerated development of salogels for diverse applications. The project will create a fertile training ground for the graduate, undergraduate students and high school students. Examples include hands-on demo on the salogel cooling pads and high-performance research computing outreach events for K-12 students. Technical Description: The ability to make re-processable salogels, i.e., polymer gels in inorganic salt hydrates (ISHs) can transform the future of thermal energy storage (TES) materials and afford novel products for thermal regulation of buildings and advanced biomedical applications. To date, the use of bulk ISHs for TES is not practical due to supercooling and fluidity/leakage during thermal cycling. This proposal aims to change that by developing a versatile family of star block copolymer gelators for tailoring salogel thermomechanical properties. This will be achieved via establishing fundamental understanding of polymer-salt-hydrate interactions and ISH solubility and gelation conditions for a wide range of synthetic polymers. Star-shaped block copolymer gelators will be designed and refined in a synergistic theory-simulation-ML-experimental approach, overcoming the laborious guess-and-check approach currently used. This work will: (i) establish fundamental polymer solubility, phase separation, and gelation mechanisms; (ii) achieve a tailorable temperature gap between ISH melting temperature and salogel gelation temperature for robust TES performance; and (iii) achieve tunable salogel rheology making them suitable for diverse TES applications and 3D printing. The project will synergistically use the expertise of the US team in polymer synthesis and characterization and assembly, simulations and theory of polymer-solvent interactions, network formation and AI/ML-enabled materials design, with the expertise of the Indian team in mechanistic modeling and 3D printing. The work will showcase the efficiency of the coherent and iterative approach which embraces material discovery and optimization using modeling, theory and ML and will establish the fundamental science that will enrich the areas of data- and computationally driven polymer and materials science. 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.