Highly Flexible, Self-Bonding, Self-Healing, and Conductive Soft Pressure Sensors Based on Dicarboxylic Cellulose Nanofiber Hydrogels.

Conductive hydrogels have gained a great deal of interest in the flexible electronics industry because of their remarkable inherent properties. However, a significant challenge remains for balancing hydrogel's conductivity, self-healing, and strength properties. Herein, double network ionic hydrogels were fabricated by concurrently introducing borax into dicarboxylic cellulose nanofiber (DCNFs) and polyacrylamide (PAM) hydrogels. The incorporation of borax provided a superabsorbent feature to the PAM/DCNF hydrogels (without borax) with the equilibrium water absorption rate increased from 552 to 1800% after 42 h. The compressive strength of the prepared hydrogel was 935 kPa compared to 132 kPa for the PAM hydrogel, with high cycling stability (stable after 1000 compression cycles with 50% strain). The hydrogel pressure sensor had a very sensitive response (gauge factor = 1.36) in the strain range from 10 to 80%, which made it possible to detect mechanical motion accurately and reliably. The developed hydrogels with high-performance, environmentally friendly properties are promising for use in future artificial skin and human-machine interface applications.

Effectiveness of cellulose and chitosan nanomaterial coatings with essential oil on postharvest strawberry quality.

Polysaccharide materials, including bagasse cellulose nanocrystals (BCNCs), chitosan nanofibers (ChNFs), and sodium alginate (SA), were blended with oregano essential oil (OEO) to make single- and multi-polysaccharide edible coating suspensions. The prepared suspensions were spray-coated on strawberry surface to form thin films with thickness varying from about 570 to 790 nm for single-polysaccharide coatings and 690-930 nm for multi-polysaccharide coatings. The coatings made with multi-polysaccharide were more effective in inhibiting fungal growth compared with single-polysaccharide coatings. Strawberry treated with SA/BCNC/ChNF/OEO formulation had only 10.8 % weight loss after nine days of storage. In contrast, uncoated and single-polysaccharide coated strawberries had >37.0 % and 28.6 % weight loss, respectively. In addition, the SA/BCNC/ChNF/OEO coating retained desired moisture, respiration rate, stiffness, firmness, and appearance properties of strawberry due to its gas barrier properties resulting from the entangled matrix structure. These results suggest that the multi-polysaccharide suspensions with OEO have a high potential for application as edible coatings for retarding senescence of strawberries.