264613 Super Gas Barrier of All-Polymer Layer-by-Layer Assemblies
Super Gas Barrier of All-Polymer Layer-by-Layer Assemblies
Layer-by-layer assembly of cationic branched polyethylenimine (PEI) and anionic poly (acrylic acid) (PAA) was investigated with regard to pH of each polymer solution during deposition. Thickness and surface roughness can be altered dramatically due to the pH-responsive morphology of PEI and PAA (from 90 nm to 4.74 mm for 30-bilayer films). Crosslinking these films with glutaraldehyde (GA) creates an inhibition of polymer interdiffusion, causing exponential film growth to be reset. The oxygen permeability was improved by increasing the number of PEI/PAA bilayers. PO2 of an 8-bilayer, glutaraldehyde-crosslinked PEI/PAA film (305 nm thick) is below 3.2×10-21 cm3·cm/cm2·s·Pa, which is believed to be the lowest permeability of an all-polymer system ever reported. Tremendous PEI/PAA interfaces result in a scrambled egg structure with a high gas barrier, so this relatively simple recipe may be of use for a variety of applications, including polymeric membranes, flexible electronics, and food packaging.
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