Optimization for size separation of graphene oxide sheets by flow/hyperlayer field-flow fractionation.

Area of Science:

• Materials Science
• Nanotechnology
• Separation Science

Background:

• Graphene oxide (GO), a derivative of graphene, possesses unique properties due to surface oxygen functional groups.
• Controlling the lateral size of GO sheets is essential for optimizing its performance in various applications.
• Existing methods often result in a wide distribution of GO sheet sizes.

Purpose of the Study:

• To optimize flow/hyperlayer field-flow fractionation (FFF) for separating graphene oxide (GO) sheets based on their lateral dimensions.
• To investigate the impact of carrier solvent, channel thickness, and flow rate on GO fractionation.
• To demonstrate the ability to collect narrow size fractions of GO.

Main Methods:

• Optimization of flow/hyperlayer FFF parameters, including carrier solvent, channel thickness (350 μm), and flow rate.
• Separation of GO sheets based on steric/hyperlayer principles.
• Characterization of collected GO fractions to verify size distribution.

Main Results:

• Optimized flow/hyperlayer FFF successfully separated GO sheets by lateral size.
• Narrow size fractions of GO were collected from different graphite sources.
• GO sheets exhibited retention times 2.2-5.0 times faster than spherical particles of equivalent diameter, attributed to hydrodynamic lift forces.

Conclusions:

• Flow/hyperlayer FFF is a viable technique for determining the size distribution of GO sheets.
• The method allows for the collection of narrow GO size fractions, essential for targeted applications.
• Lateral dimension control of GO is achievable and critical for its utility.