Polyelectrolyte Coacervate Coatings That Dramatically Improve Oxygen Barrier of Paper

Paper-based food packaging is lightweight, low cost, and highly flexible, but it suffers from a very high oxygen transmission rate (OTR ∼ 11,100,000 cc/(m2·day·atm)). Herein, two polyelectrolyte-based coacervate coatings were studied as oxygen gas barriers on kraft builder's paper. A single coating deposition of a polyethylenimine-poly(acrylic acid) coacervate, adding less than 20% to the paper's weight, reduced the OTR to 164,000 cc/(m2·day·atm). This work not only demonstrates a significant OTR improvement of a poor oxygen barrier material, but also provides the foundation for polyelectrolyte-based layers to be deposited on cellulosic materials at an industrial scale.