Cellulose nanofibrils and silver nanowires active coatings for the development of antibacterial packaging surfaces Hugo Spieser (Validation) (Investigation) (Writing -original draft) (Writing -review and editing) (Visualization), Aurore Denneulin (Conceptualization) (Writing -review and editing) (Supervision) (Funding acquisition), Davide Deganello (Writing -review and editing) (Supervision), David Gethin (Writing -review and editing) (Supervision), Rajesh Koppolu (Investigation) (Writing -review and editing), Julien Bras (Conceptualization) (Writing -review and editing) (Supervision) (Funding acquisition)

TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl)-oxidized cellulose nanofibrils (T-CNF) and silver nanowires (Ag NWs) were formulated as active inks. Their rheological properties were investigated to design optimal conditions for processing by the screen-printing process, with the aim of preparing antibacterial patterns. Rheological experiments mimicking the screen-printing process was applied to different ink formulations to investigate their thixotropic and viscosity properties. The experiments conducted at 1% wt total mass content and different ratios of T-CNF/Ag NWs, showed that the recovery (%), the recovery time and the viscosity are formulation dependent. A ratio 2:1 (T-CNF:Ag NWs) and total mass content of 2.5% wt was then selected to prepare an ink suitable for screen printing. Printing defects were corrected by addition of water-soluble polymer hydroxypropyl methylcellulose (HPMC).The selected formulation printed on flexible polyethylene terephthalate (PET) substrate displayed a 67.4% antibacterial activity against E. Coli in a standard contact active test, with a transparency superior to 70%, proving the promising features of the developed solution for active packaging applications.