Chemomechanics of Dynamic Polymers

Unlike living organisms, which continuously grow, remodel, and adapt to changing environments, most engineering materials remain mechanically static once fabricated because their internal load-bearing networks cannot evolve. In recent advances, however, polymer materials with dynamic chemistry have shown the capability of post-fabrication growth and restructuring. There is a need to develop a material behavior framework capable of predicting how chemical reactions, molecular transport, and deformation collectively govern polymer network evolution in these materials. This project supports fundamental research to establish the mechanics of open, network-evolving materials operating far from thermodynamic equilibrium. The resulting knowledge will extend classical mechanics beyond materials with fixed internal structures and provide a scientific foundation for understanding how evolving material architecture governs mechanical behavior. These advances are expected to enable engineered materials that can be repaired, repurposed, and recycled, reducing energy consumption and material waste. The project will integrate research into interdisciplinary education spanning mechanics, chemistry, and materials science through existing and new course development. It will also engage students and the public through outreach activities via various mechanisms, e.g., permanent, mobile, and web-based DIY content, illustrating how mechanics governs growth and form in both living and engineered systems, such as mollusk shells and soft robots, respectively. This project will establish a predictive mechanics framework for materials whose load-bearing networks continuously evolve through coupled reactions, transport, and deformation, and thus, operate far from equilibrium. The research will formulate thermodynamically consistent constitutive laws based on statistical descriptions of evolving polymer networks, allowing growth, degrowth, network remodeling, and stiffness evolution to emerge naturally from coupled chemomechanical processes rather than being prescribed phenomenologically. The theoretical framework will be implemented computationally and integrated with mechanics-based experiments to identify intrinsic constitutive parameters and validate model predictions. The project will also establish new experimental mechanics methodologies by formulating rheological measurements, relaxation indentation, and growth kinetics as mechanics-based boundary value problems for quantitative characterization of coupled reaction, transport, and deformation in evolving materials. Dynamic polymer systems with systematically varied reaction kinetics, transport properties, and network architectures will serve as model material platforms for probing reaction-controlled, transport-controlled, stress-regulated, and intermediate regimes of network evolution. 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.