MSE PhD Proposal – Kesong Hu
Dr. Vladimir Tsukruk (Advisor, MSE)
Dr. Kyriaki Kalaitzidou (ME)
Dr. Satish Kumar (MSE)
Dr. Zhiqun Lin (MSE)
Dr. Eric Vogel (MSE)
Integration and Modification of Graphene with Biomacromolecules for Structural and Functional Applications
This study is focused on an understanding of the fundamental principles of fabricating polymer nanocomposite materials and optimizing their structural and functional properties. The status of the research on polymer nanocomposites has been critically reviewed and the motivation and challenges to develop ultra-robust, functional nanocomposite films are presented. Silk fibroin and graphene oxide are chosen as the model system to investigate the optimized interfacial interactions between biomacromolecules and the heterogeneous, most widely available graphene derivative. The interfacial interaction between silk fibroin and graphene oxide has been carefully investigated through layer-by-layer assembly technique to get a clear image on the importance of the matching surface domains for heterogeneous components in nanocomposites and ultrahigh mechanical properties has been reported for the ultra-thin nanocomposite membranes. Theoretical analysis revealed an interphase reinforcing layer exists between the graphene oxide and the pristine silk fibroin due to the high-density weak interactions at the matrix-filler interface. In addition to nanomembrane, we utilized the same principle to fabricate microfilms by vacuum flocculation of graphene oxide – silk fibroin mixtures. The resulting graphene “biopaper” show significant improvement in mechanical properties and water resistance in contrast to pristine graphene oxide papers. An innovative technique has also been applied to reduce patterned surface of the graphene biopaper to restore its electrical conductivity by using active metal as the reducing agent in ambient condition.
In addition to the preliminary results, we plan to continue the research by imaging individual silk fibroin macromolecules on graphene oxide to provide direct evidence of the preferential adsorption and collectively manipulate the secondary structures of the silk fibroin molecules to achieve higher interfacial interaction thus achieving superior mechanical performance. The precise patterned reduction in microscale of the graphene biopaper will also be carried out to explore the possibility of fabricating flexible, bioelectronic devices directly on the surface of the ultra-robust graphene biopaper.