Anomalous molecular infiltration in graphene laminates

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Graphene laminated (GL) coatings offer advanced barrier properties.
• Few layer graphene (FLG) nanocrystals deposited on polyethylene (PE) films.
• Mechanical rubbing technique for GL coating deposition.

Purpose of the Study:

• Investigate molecular transport through GL/PE bilayer membranes.
• Characterize gas permeation dynamics for CO2, N2, and H2.
• Understand the underlying transport mechanism in GL coatings.

Main Methods:

• Gas phase permeation technique under transient conditions.
• Monitoring CO2, N2, and H2 transport fluxes.
• Positron annihilation lifetime spectroscopy (PALS) for cavity analysis.

Main Results:

• Observed anomalous molecular transport behavior.
• Penetrant concentration follows compressed exponential kinetics.
• Relaxation time is thermally activated and molecule-size dependent.
• Cavity sizes in GL coatings are comparable to molecular kinetic diameters.
• Transport mechanism attributed to configurational diffusion in nano-channels.

Conclusions:

• GL coatings exhibit unique transport characteristics.
• The findings support a configurational diffusion model for molecular infiltration.
• GL coatings demonstrate potential for advanced gas barrier applications.