Monolayer Graphene Transfer onto Hydrophilic Substrates: A New Protocol Using Electrostatic Charging

Area of Science:

• Materials Science
• Chemical Engineering
• Membrane Technology

Background:

• Developing advanced membranes for efficient separation processes is crucial.
• Graphene's unique properties offer potential for enhanced membrane performance.
• Reliable transfer of graphene onto various substrates remains a challenge.

Purpose of the Study:

• To develop and evaluate a novel electrostatic method for transferring monolayer graphene onto hydrophilic micro/ultra-filtration substrates.
• To assess the quality of transferred graphene using surface analysis techniques.
• To investigate the ion rejection capabilities of the resulting graphene-based membranes.

Main Methods:

• Monolayer graphene transfer using electrostatic charging during wet transfer.
• Surface characterization via water contact angle (CA), atomic force microscopy (AFM), and field emission scanning electron microscopy (FESEM).
• Ion transport studies using potassium chloride (KCl) solutions.

Main Results:

• Successful transfer of graphene onto polyvinylidene difluoride (PVDF), polyethersulfone (PES), and other membranes.
• Initial KCl ion rejection rates of 65-70% achieved, with smoother substrates showing higher efficacy.
• Defect sealing using Nylon 6,6 interfacial polymerization enhanced KCl ion rejection to 85%.

Conclusions:

• The electrostatic transfer method provides a viable route for creating graphene-based membranes.
• Membrane performance, particularly ion rejection, is influenced by substrate properties and graphene layer integrity.
• Defect sealing significantly boosts the separation efficiency of graphene composite membranes.