Environmental friendly and sustainable gas barrier on porous materials: Nanocellulose coatings prepared using spin- and dip-coating

In this study, environmental friendly and sustainable coatings of nanocellulose (NC) were prepared using spin- and dip-coating methods, on two different porous cellulose substrates. Microscopy studies showed that spin-coating technique was suitable for the substrate with smaller pore size, while the dip-coating was suitable for the substrate with larger pore size. The coating thickness ranged from some hundreds of nanometers for the spin-coated layers, to some micrometers for the dip-coated ones. It was also seen that the contact angle increased with the coating thickness and roughness. NC coating resulted in low oxygen permeability (between 0.12 and 24 mL*mu m/(m(2)*24h*kPa)) at 23% RH, but at 50% RH the oxygen permeability was too high to be measured, except for the dip-coated sample with 23 mu m thickness. Also, it was seen that eight month storing reduced the barrier properties of the coatings when compared with fresh materials. These results indicate that NC coatings have a great potential as sustainable alternative coating on paperboard. (C) 2015 Elsevier Ltd. All rights reserved.