Stretchable gas barrier achieved with partially hydrogen-bonded multilayer nanocoating

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Layer-by-layer deposition of polyelectrolytes and clay nanoplatelets creates super gas barrier nanocoatings.
• These nanobrick wall thin films offer gas barrier properties comparable to SiOx and metallized films.
• Existing nanocoatings are stiff and lose barrier performance upon significant stretching (≥ 10% strain).

Purpose of the Study:

• To develop a stretchable high gas barrier thin film by incorporating hydrogen-bonding polyglycidol (PGD) layers.
• To enhance the mechanical properties of existing electrostatic layer-by-layer assemblies for improved stretchability.
• To evaluate the gas barrier performance of the modified nanocoatings under strain.

Main Methods:

• Fabrication of trilayer films using electrostatically bonded polyethylenimine (PEI) and montmorillonite (MMT) clay, with added hydrogen-bonding PGD layers.
• Characterization of gas barrier properties using oxygen transmission rate (OTR) measurements.
• Mechanical testing involving stretching of the thin films to assess strain-induced barrier degradation.

Main Results:

• A 125-nm thick PEI-MMT bilayer film showed a >40x increase in OTR after 10% stretching.
• PGD-PEI-MMT trilayer films of similar thickness maintained their gas barrier performance after stretching.
• The stretchable trilayer system exhibited an OTR three times lower than the PEI-MMT bilayer system post-stretching.

Conclusions:

• This study presents the first stretchable high gas barrier thin film.
• The incorporation of PGD layers significantly improves the stretchability and maintains the gas barrier of nanocoatings.
• The developed material holds potential for applications requiring pressurized elastomers and flexible barrier packaging.