Strong, Conductive, Foldable Graphene Sheets by Sequential Ionic and π Bridging

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Reduced graphene oxide (rGO) shows promise for advanced materials.
• Existing methods for rGO sheet production often involve polymers or high temperatures, limiting applications.
• Enhancing mechanical strength, toughness, and electrical conductivity of rGO is crucial for broader technological adoption.

Purpose of the Study:

• To develop an inexpensive, low-temperature, polymer-free process for producing high-performance rGO sheets.
• To investigate the effects of ionic and π-π bonding agents on the properties of rGO sheets.
• To achieve superior mechanical and electrical characteristics in rGO sheets for demanding applications.

Main Methods:

• Evaluation of ionic bonding agents (Cr³⁺) and π-π bonding agents (pyrene end groups) on rGO sheets.
• Systematic application of single and combined bonding agents to rGO.
• Characterization of mechanical properties (tensile strength, toughness) and electrical conductivity.
• Assessment of property retention under mechanical stress, ultrasonic treatment, and corrosive environments.

Main Results:

• The π-π bonding agent alone significantly improved rGO properties compared to the ionic agent.
• Successive application of ionic and π-π bonding agents yielded the highest tensile strength (821 MPa) and toughness (20 MJ m⁻³).
• Achieved high electrical conductivity (416 S cm⁻¹) with excellent long-term stability in corrosive solutions and resistance to mechanical stress and ultrasonication.

Conclusions:

• A novel, cost-effective, low-temperature method for producing high-performance rGO sheets has been established.
• The synergistic effect of combined ionic and π-π bonding agents is key to maximizing rGO sheet performance.
• The resulting rGO sheets demonstrate significant potential for applications in aerospace and flexible electronics due to their enhanced durability and conductivity.