Canna-inspired superhydrophobic and icephobic regenerated cellulose based hierarchical intelligent colorimetric sensing film for food real-time visual monitoring

Unsafe food cause serious threat to public health and the economy, exploiting effective food quality assessment strategies has attracted concerns worldwide. Herein, inspired by Canna micro-nano hierarchical structure, a generic, facile, and highly processable roll-to-roll and solvent evaporation-induced self-assembly fabrication method is introduced to fabricate regenerated cellulose based superhydrophobic and icephobic hierarchical colorimetric sensing film for real-time visual monitoring of food freshness. The synergistic effect from macromolecular chains attraction and nanoscaled aggregation renders the colorimetric sensing film with excellent mechanical strength of 105.07 MPa and superhigh shear modulus of 17.28 GPa. Upon applied tension, the vigorous intermolecular interactions make the film extraordinary structure stability. The optimized colorimetric sensing film exhibits microscaled pores for sensing performance and three-dimensional nanoflower morphologies for superhydrophobic (water contact angle of 155.1 °and roll-off angle of 7.8°) and icephobic that delay the freezing time of 40 μL water droplets (45 s to 265 s) and reduce the bonding strength of ice (599.72 kPa to 45.53 kPa). What counts is the first time bestowed with icephobicity to food freshness colorimetric sensing film, which mitigating the interference of the covered ice layer against the colorimetric, and providing a more reasonable monitoring in food freshness. These results benefit for stimulating new design principles of colorimetric sensing films, and also provide promising applications in extremely cold environments.