All-Organic Multilayer Coatings for Advanced Poly(lactic acid) Films with High Oxygen Barrier and Excellent Antifogging Properties

Abstract

Poly­(lactic acid) (PLA) has been increasingly employed as a promising packaging material. Unfortunately, PLA film suffers low oxygen barrier and poor antifogging issues, which extremely restrict its practical applications. Despite some progress, to date it remains a challenge to construct a biodegradable, transparent, highly oxygen-barriered and antifogging coating for the PLA film via a facile approach. Here, we report a facile construction of biodegradable and all-organic coating with high transparency via hydrogen-bonded layer-by-layer assembly of poly­(vinyl alcohol) (PVA) and tannic acid (TA). With the presence of 20 bilayers of PVA and TA, the oxygen permeability is reduced to 0.52 × 10–16 cm3·cm/[cm2·s·Pa], approximately 450 times lower than that of PLA film. Moreover, fogging issue for PLA film can be effectively addressed only with five bilayers of PVA and TA. These improvements are attributed to the hydrogen-bonding interactions and polyphenol groups within the multilayer coating. This work may provide a facile strategy for the design of biodegradable and highly transparent coating for the high oxygen barrier and antifogging applications by using organic molecules as building blocks.

Biopolymer Coatings for Biomedical Applications

“…The bilayer PCL/FHA coatings provide good corrosion resistance and biomineralization formation, which can be used for implant applications. In another study, in order to improve the antifogging and low oxygen barrier of PCL, multilayer coatings of poly(vinyl alcohol) (PVA) and tannic acid (TA) bilayers were used which reduced the oxygen permeability with the presence of 20 bilayers and fogging was controlled with five bilayers [ 85 ]. This work opens up a way to design transparent biodegradable coatings with oxygen barrier and antifogging properties for various applications.…”

Effect of PVOH/PLA + Wax Coatings on Physical and Functional Properties of Biodegradable Food Packaging Films

“…In this regard, the deposition of functional bio-based coatings is a promising approach to improving the surface characteristics of substrates (i.e., adhesion, wettability, water repellence, anti-corrosion, antioxidant, antimicrobial and gas barrier properties) without compromising the biodegradable and/or recyclable features [ 17 ]). Polymeric coatings based on chitin nanofibrils, chitosan or PLA-based composites demonstrated their effectiveness for antimicrobial packaging [ 18 , 19 , 20 , 21 , 22 , 23 ]; hydrophobic properties can be imparted by including chitin or waxes [ 24 , 25 , 26 ] or by acrylic-modified crosslinkable chitosan nanocoatings [ 27 ]; among efficient oxygen-barrier layers, crosslinked proteins [ 28 , 29 , 30 , 31 , 32 ], cellulose nanocrystals [ 33 , 34 , 35 ] and poly(vinyl alcohol) [ 36 , 37 , 38 , 39 , 40 ] have recently received attention due to their excellent barrier performance.…”

“…To the best of the authors’ knowledge, this was the first time that the combined use of PVOH and PLA + wax for double coatings was proposed to achieve this target. Moreover, very few studies focused on the development of double- or multiple-coated films [ 36 ]; those that did mainly did so through the layer-by-layer (LBL) assembly technique [ 49 ], mostly for medical applications [ 50 ], electrically conductive coatings [ 51 ] and devices for drug delivery [ 52 ]. The produced films were characterized by differential scanning calorimetry (DSC) and infrared spectroscopy (ATR FT-IR) to investigate their inherent chemical and thermal properties, as well as possible interactions between the micronized wax and the PLA matrix.…”

Sustainable, self-cleaning, transparent, and moisture/oxygen-barrier coating films for food packaging

“…12,13 An emerging approach uses layer-by-layer assembly (LbL) of sustainable materials via dip coating on poly(lactic acid) to achieve an all-organic functional packaging. 14,15 However, the dip coating method requires dedication and stringent control to homogenously wet the substrate and obtain a desired deposition of thin films. 16 To recycle the functional packaging film, the coating layer should be delaminated from the film.…”