Polymer-graphene oxide quadlayer thin-film assemblies with improved gas barrier

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Developing advanced barrier coatings is crucial for gas separation and packaging.
• Existing coatings often face challenges with performance under humid conditions.

Purpose of the Study:

• To create a novel multilayer nanocoating using chitosan (CH), poly(acrylic acid) (PAA), and graphene oxide (GO).
• To evaluate the gas barrier properties and selectivity of the developed coating, particularly under varying humidity.
• To optimize the coating for potential applications in gas purification and packaging.

Main Methods:

• Utilized layer-by-layer assembly to construct quadlayers (QLs) of CH, PAA, CH, and GO.
• Characterized film structure using electron microscopy.
• Investigated the effect of pH deviation on polymer matrix formation.
• Thermally reduced GO to enhance film hydrophobicity and barrier performance.

Main Results:

• Achieved a highly ordered nanobrick wall structure with complete GO coverage.
• A 5 QL assembly exhibited oxygen permeability comparable to SiOx coatings (3.9 × 10(-20) cm(3) cm cm(-2) Pa(-1) s(-1)).
• Thermal reduction of GO significantly increased H2/CO2 selectivity from 5 to 215, surpassing Robeson's upper bound.

Conclusions:

• The developed water-based multilayer nanocoating offers excellent gas barrier and separation capabilities.
• The tunable properties and enhanced performance under humidity make it promising for gas purification and advanced packaging.
• This approach provides a viable alternative to traditional barrier materials.