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Nanopaper prepared from cellulose nanofibers (CNFs) is a kind of promising substrate for various high-tech devices. However, several drawbacks including poor water stability and weak corrosion resistance still remain, which limit the practical applications of the nanopaper. Herein, we present a simple and low-cost method for fabricating transparent and superhydrophobic nanopaper by spraying fluorinated silica/multi-walled carbon nanotubes (SiO

Nanocomposite hydrogels consisting of a synthetic matrix reinforced by nanosized crystalline polysaccharides offer significant potential in various fields. Different from nanocellulose, the combination of nanochitin with synthetic polymers to obtain nanocomposite hydrogels has not been extensively and systematically studied. Herein, a physically and chemically dual crosslinked nanocomposite hydrogel was successfully synthesized, where chitin nanowhiskers (ChNWs) and Zn2+ were incorporated within polyacrylamide (PAAm) matrix. Nanochitin/metal ion dual reinforcement imparts increased elasticity, enhanced mechanical properties, and improved recovery performance to PAAm network. The PAAm/ChNWs/Zn2+ hydrogel could be stretched to over 13 times its original length with tensile strength of 321.9 ± 8.2 kPa, and restore its original shape rapidly even when compressed at a strain of 95% with a corresponding compressive strength of 6.95 ± 0.20 MPa. The multiple crosslinks and interactions among ChNWs, Zn2+ and synthetic polymeric network were investigated. Moreover, the hydrogel was applied in drug release and soft bioelectronics.

Developing green substrates based on cellulose to substitute synthetic plastics meet the requirement for the sustainable future. However, cellulose-based substrates supporting for building electronic devices are usually opaque and highly hydrophilic, which ultimately limits the performance of optoelectronic devices. Herein, we report a new avenue for fabrication of highly transparent, weakly hydrophilic and biodegradable cellulose film. The acquired cellulose film not only has high transparency (over 90%), but also displays weak hydrophilicity (∼79° of initial water-contact angle) and still remains 3.5 MPa of tensile strength after soaking for two days in deionized water. Additionally, the degradation half-life of cellulose film is 20 days, and the cellulose films also have better thermostability. Moreover, the flexible electroluminescent devices have been successfully constructed by using this cellulose film as a green substrate. This novel strategy will greatly enrich the applications of cellulose films for next generation green electronics.

Nanopaper prepared from cellulose nanofibers (CNFs) is a kind of promising substrate for various high-tech devices. However, several drawbacks including poor water stability and weak corrosion resistance still remain, which limit the practical applications of the nanopaper. Herein, we present a simple and low-cost method for fabricating transparent and superhydrophobic nanopaper by spraying fluorinated silica/multi-walled carbon nanotubes (SiO2/MWCNTs) composite on the nanopaper. A series of functional nanopaper were fabricated, which shows excellent performance of water repellency, chemical stability, conductivity, thermostability and self-cleaning property. Among them, the nanopaper modified with the composite containing 0.5 wt% MWCNTs has a water contact angle of about 163°, transparency of 79.96% and the sheet resistance of 3.15 × 106 Ω sq−1. The combination of the promising features in a material offers attractive prospects, and enables our nanopaper could be tailored for emerging applications such as flexible electronics, display protection and intelligent packages.

A novel multivalent cations-triggered shape memory hydrogels were synthesized in a one-pot method, and interpenetrating double network was formed by chemically cross-linked polyacrylamide (PAM) network and physically cross-linked sodium carboxymethyl cellulose network. The temporary shape was fixed by complexation between a native biopolymer, sodium carboxymethyl cellulose (CMC), and transition metal ions, specifically Fe3+, Ag+, Al3+, Cu2+, Ni2+, and Mg2+. In particular, CMC-Fe3+ hydrogel exhibits excellent shape fixity ratio (95%). Therefore, we chose PAM/CMC1.0-Fe3+ hydrogel as the model material and further investigated its shape recovery process. It was found that a wide range of molecules and anions could be applied to break off the temporary cross-links between CMC and Fe3+. The PAM/CMC composite hydrogels also exhibited excellent tunable mechanical properties. The mechanical properties of the composite hydrogel can be adjusted by changing the cross-linking densities. The presented strategy could enrich the construction as well as application of biopolymers based shape memory hydrogels.