Professor Yao Lin has been awarded a five-year NSF grant (DMR #2210590, $719,664), for his research project, “Advancing Processability and Material Performance of Synthetic Polyamino Acids with Transformable Secondary Structures.”

Dynamic transition from helices to sheets in fibrous proteins facilitates a remarkable increase in the strength, stiffness, and energy dissipation capacity. Polyamino acids (PAAs), also known as synthetic polypeptides, can adopt analogous secondary structures. However, inducing the structural transitions in the solid PAA of high molecular weights (MWs) is a largely unmet challenge. As a result, many of the PAA materials either have poor thermomechanical properties or are incompatible with polymer processing techniques such as extrusion and compression molding. This project aims to develop a general strategy to significantly improve the thermomechanical properties and processability of synthetic PAAs by taking advantage of metastable, transformable structures of PAAs and control over their in-situ transition and hierarchical organization.

The findings from this project may enable the generation of polymeric systems that will approach the level of sophistication and versatility found in some of nature’s biomaterials. The research also provides a model system of synthetic polymers with intrinsic secondary structures in which the different partitioning of intramolecular and intermolecular networks determines the macroscopic properties of materials, enabling comparison of the experimental results with predictions from simulations and modeling.

Graduate and undergraduate students will be trained on bioinspired polymeric materials and acquire skills in polymer synthesis, material characterization, mechanics, and computer simulations.