Cellulose nanocrystals as new bio-based coating layer for improving fiber-based mechanical and barrier properties

In this work, we explored the elaboration of new smart paper by coating fiber-based materials with CNC for possible use in packaging. Particularly, we investigated application of a 100% CNC layer onto a substrate. Mainly due to the cost and limited availability of CNC on a large scale, few studies have examined these opportunities. Several layers of CNC were deposited onto a paper material using the bar-coating process to improve relevant properties of the paper surface. Surface analyses (atomic force microscopy, scanning electron microscopy, and transmission electron microscopy) were performed to elucidate the CNC network at the paper surface. Structural and mechanical properties of the final materials were evaluated. Results of general interest were obtained about barrier properties. The air barrier and grease resistance improve only with the paper coated with CNC. To complete this research, a small amount of polyethylene glycol was added to reinforce the brittle CNC coating and clearly enhance barrier properties of the paper.