K. Song, W. Xu, S. Jambhulkar
Arizona State University Polytechnic,
Keywords: graphene, polymer, composite, mechanical, electrical, sensing
Summary:Graphene has been frequently included in the polymeric matrices for mechanical enhancement, electrical/thermal conductivity improvement, super capacitance or energy storage increases. However, the control of individual graphene regarding its surface flatness and directional orders have not been comprehensively reported. The main challenge is the thermodynamic instability of the graphene layers under ambient conditions (e.g., curling and crumpling at the room temperature). This study reports the assistance of polymer layers in facilitating graphene surface flatness and directional orders. The achievement is through the customization of spinning spinneret that can simultaneously laminate soft-matter macromolecules and stiff particle graphite. During the fiber treatment procedures, the stacked layers in graphite will be exfoliated and oriented along the shear stress direction, leading to highly oriented and less stacked graphene materials. As a result, the modulus and strength can be significantly improved in polymers such as polyvinyl alcohol (PVA) and thermoplastic polyurethane (TPU). The sensitivity to mechanical strains and compression stresses was effective, down to 0.1 psi. The sensing selectivity to different gaseous chemicals was highly efficient with a concentration of a few ppm. This project demonstrated the efficiency in achieving graphene flatness in advanced composites for sensor applications.