On the development of nanofibrillated cellulose templates for functional materials

Challenges on the manufacture of nanocellulose films are non-trivial when it comes to obtain large, smooth and fully reactive nanocellulose films. Among such challenges, the removal of high amounts of water present in gel-like nanocellulose suspensions has been one of the main drawbacks in terms of up-scaling nanofibrillated cellulose (NFC) film manufacture technology. Furthermore, during film formation, the hydrophilic nature of nanocellulose favours the accumulation of airborne contaminants on its surface, diminishing its reactivity by hampering potential sites for further chemical functionalization and restricting its potential applications. In this contribution recent advances in up-scaling NFC film manufacturing technology will be discussed and special focus will be dedicated to our current efforts on the development of a strategy to control, effectively activate and thus enhance the reactivity of nanocellulose film surfaces. We had developed a simple, solvent-free and low cost method based on the oxidative properties of UV radiation and ozone that allows the effective removal of contaminants from nanocellulosic surfaces, which remain clean and reactive for at least a week. Significant improvements in surface modification, degrees of substitution and printing quality were observed upon activation of NFC films. Such development has a direct impact in several applications for NFC substrates such as flat panel displays, printed electronics and diagnosis, packaging and health care products to name a few.