Nano-Brick Wall Architectures Account for Super Oxygen Barrier PET Film by Quadlayer Assembly of Polyelectrolytes and α-ZrP Nanoplatelets

Abstract

Nanobrick wall hybrid coating with super oxygen barrier properties were fabricated on polyethylene terephthalate (PET) film using a quadlayer (QL) assembly of polyelectrolytes and nanoplateles. A quadlayer assembly consists of three repeat units of polyacrylic acid (PAA), poly (dimethyl diallyl ammonium chloride) (PDDA) and layered α-zirconium phosphate (α-ZrP). PDDA with positive charges can assemble alternatively with both α-ZrP and PAA with negative charges to form nanobrick wall architectures on the surface of PET film via the electrostatic interaction. The lamellar structure of α-ZrP platelets and the dense QL assembly coating can greatly reduce the oxygen transmission rate (OTR) of PET film. Compared to pristine PET film, the OTR of PET (QL)19 is reduced from 57 to 0.87 cc/m2/day. Moreover, even with 19 QLs coating, PET (QL)19 composite film is still with an optical transparency higher than 90% and a haze lower than 10%. Therefore, the transparent PET (QL)n composite films with super oxygen barrier properties show great potential application in food packaging and flexible electronic packaging.

α-Zirconium Phosphate Nanoplatelets with Covalent Modifiers for Exfoliation in Organic Media

“…Solid-State NMR. Several materials synthesized were characterized with 31 P (Figure 2) and 13 C solid-state NMR (Figure S9). Previously, 31 P solid-state NMR has been used to demonstrate a P−O−C bond after epoxide addition to ZrP by an upfield shift of the phosphorus signal of 3−5 ppm.…”

“…The 31 P MAS NMR spectra were referenced with respect to 85% H 3 PO 4 (aq) by setting the 31 P NMR peak of solid (NH 4 )H 2 PO 4 as the external standard to +0.81 ppm. 13 C solid-state NMR were also recorded on the Bruker Avance 400 spectrometer with the 4.0 mm probehead. Cross-polarization (CP-MAS) techniques were used with optimization of the Hartmann−Hahn.…”

“…ZrP is a layered 2D material, often considered a synthetic clay, with many applications including ion exchange, − optical switches, catalysis, − and fillers in polymer matrices due to enhanced material properties in areas, for example, gas barrier, − mechanical, , and flame retardation. , However, commercial use as fillers in polymer matrices has been limited and with lower concentrations of nanoclay. , The lack of industrial use is partially due to difficulty in achieving exfoliation and dispersion of the nanoclay, which leads to significantly lower performance than theoretical predictions. Because of the nature of the phosphate group and charge associated with it, ZrP is hydrophilic in nature.…”

Nanocomposites for Food Packaging Applications: An Overview

“…Furthermore, the 20 tri-layer film was at the detection limit of commercial equipment (0.005 cm 3 /m 2 day), a 1600 times improvement over 179 μm PET (8.6 cm 3 /(m 2 day atm)) [ 99 ]. Similarly, a quad-layer assembly of polyelectrolytes and nanoplatelets on a PET substrate was also reported [ 100 ]. In this case, the quad-layer assembly consisted of three repeating units of poly(acrylic acid) (PAA), poly(dimethyl diallyl ammonium chloride) (PDDA), and layered α-zirconium phosphate (α-ZrP).…”

Nano-inspired oxygen barrier coatings for food packaging applications: An overview

“…Final PI films coated with the smectic α-ZrP nanoplatelet/epoxy nanocomposite exhibited outstanding oxygen barrier properties (Wong et al, 2014). More recently, α-ZrP was used in combination with PAA and poly(dimethyl diallyl ammonium chloride) (PDDA) to yield a quadlayer (QL) assembly that generated a nanobrick wall hybrid coating on PET film (25 μm thick) with super oxygen barrier properties (Han et al, 2018).…”