Sequentially Bridged Graphene Sheets with High Strength, Toughness, and Electrical Conductivity


We here show that infiltrated bridging agents can convert inexpensively fabricated graphene platelet sheets into high-performance materials, thereby avoiding the need for a polymer matrix. Two types of bridging agents were investigated for interconnecting graphene sheets, which attach to sheets by either π–π bonding or covalent bonding. When applied alone, the π–π bonding agent is most effective. However, successive application of the optimized ratio of π–π bonding and covalent bonding agents provides graphene sheets with the highest strength, toughness, fatigue resistance, electrical conductivity, electromagnetic interference shielding efficiency, and resistance to ultrasonic dissolution. Raman spectroscopy measurements of stress transfer to graphene platelets allow us to decipher the mechanisms of property improvement. In addition, the degree of orientation of graphene platelets increases with increasing effectiveness of the bonding agents, and the interlayer spacing increases. Compared with other materials that are strong in all directions within a sheet, the realized tensile strength (945 MPa) of the resin-free graphene platelet sheets was higher than for carbon nanotube or graphene platelet composites, and comparable to that of commercially available carbon fiber composites. The toughness of these composites, containing the combination of π–π bonding and covalent bonding, was much higher than for these other materials having high strengths for all in-plane directions, thereby opening the path to materials design of layered nanocomposites using multiple types of quantitatively engineered chemical bonds between nanoscale building blocks.


Includes supplementary material


Adhesives, Graphene, Nanocomposites (Materials)--Graphene, Oxides--Graphine

This work was supported by the Excellent Young Scientist Foundation of the National Natural Science Foundation of China (NSFC) (Grant 51522301), the NSFC (Grants 21273017 and 51103004), the Program for New Century Excellent Talents in University (Grant NCET-12-0034), the Fok Ying-Tong Education Foundation (Grant 141045), the 111 Project (Grant B14009), the Aeronautical Science Foundation of China (Grants 20145251035 and 2015ZF21009), State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology (Grant oic-201701007), the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University (Grant LK1710), the Fundamental Research Funds for the Central Universities (Grants YWF-16-BJ-J-09 and YWF-17-BJ-J-33), and the Academic Excellence Foundation of Beihang University for PhD Students. Support in the United States was from Air Force Office of Scientific Research Grants FA9550-15-1-0089 and FA9550-12-1-0035 and NSF Award 1636306.


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