Fig. 2 | Nature Communications

Fig. 2

From: High gas barrier coating using non-toxic nanosheet dispersions for flexible food packaging film

Fig. 2

Structure of barrier films containing LDH nanosheets. a Schematic of coating process and tortuous pathway. The coating solution was spread and coat on the substrate PET film by a semi-automatic bar coater to form the aligned structure of LDH NS in PVA matrix. The well aligned impermeable LDH forces gas molecules to go through a tortuous pathway to diffuse through the film. b Coating layer thickness plotted as a function of coating gap. Error bar represents the standard deviations of more than 10 measurements. The inset shows the coating layer thickness of film coated with 24 μm coating gap measured by AFM. The coating solution used to coat all the films contains 3 wt% LDH NS and 2 wt% PVA. c Transparency and haze of the barrier films of PET, 10 wt% PVA coated PET, and 10 wt%-60% LDH coated PET films. d Cross-sectional TEM image of the barrier film containing 60% LDH showing ordered structure where LDH nansheets are aligned parallel to each other. Pole figure measurements of LDH/PVA phase and LDH/Glycine phase in the barrier films (all the films were coated with 24 μm gap) containing 20% (e, f), 60% (g, h) and 90% LDH (i, j) in the coating layer. k Summary of degree of orientation of LDH nanosheets calculated by Eq. (3). Error bar represents standard error from the curve fitting. The total solid content of all the coating solutions (except in c) were 5 wt% for all the coated film samples discussed in this figure. PVA with MW of 67,000 g mol−1 was used for all the coating films

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