Conductive hydrogels are promising interface materials utilized in bioelectronics for human-machine interactions. However, the low-temperature induced freezing problem and water evaporation-induced structural failures have significantly hindered their practical applications. To address these problems, herein, an elaborately designed nanocomposite organohydrogel is fabricated by introducing highly conductive MXene nanosheets into a tannic acid-decorated cellulose nanofibrils/polyacrylamide hybrid gel network infiltrated with glycerol (Gly)/water binary solvent. Owing to the introduction of Gly, the as-prepared organohydrogel demonstrates an outstanding flexibility and electrical conductivity under a wide temperature spectrum (from −36 to 60 °C), and exhibits long-term stability in an open environment (>7 days). Additionally, the dynamic catechol-borate ester bonds, along with the readily formed hydrogen bonds between the water and Gly molecules, further endow the organohydrogel with excellent stretchability (≈1500% strain), high tissue adhesiveness, and self-healing properties. The favorable environmental stability and broad working strain range (≈500% strain); together with high sensitivity (gauge factor of 8.21) make this organohydrogel a promising candidate for both large and subtle motion monitoring.

The ionic conducting hydrogel has attracted tremendous attention in fabricating flexible artificial skin-like devices. However, there are still unsolved challenges in hydrogel-based ionic skins, such as poor fulfillment of stretchability and compliance and weak interface interaction, as well as single sensory function. Herein, a high-performance organohydrogel-based ionic skin is facilely fabricated through one-step UV-initiated polymerization, in the presence of a polyacrylamide/cellulose nanofibril (PAAm/CNF) hybrid skeleton, a tannic acid (TA)-functionalized interface, and electrolytes (NaCl) dissolved in a glycerol–water binary solvent network. The design strategy demonstrates a profound synergistic effect of interpenetrating networks and interbonding structure in improving ultrastretchability (up to 1430%), suitable Young’s modulus (≈23 kPa), and high ionic conductivity (2.7 S m–1). Inspired by the adhesive mechanism of catechol groups in the mussel foot proteins, the TA component provides a durable interfacial contact (self-adhesiveness ≈ 103 N m–1) and unexpected UV-blocking capability (efficiency >99.9%). Moreover, by introducing a glycerol/water solvent system, the organohydrogel achieves desirable environmental stability. Furthermore, benefiting from the superior mechanical response and thermal perception capacities, our ionic skin can be assembled as capacitance sensors for real-life motion monitoring as well as thermistors for dynamic temperature detection.

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Lignin-containing cellulose nanopaper (LCNP) has emerged as a new generation of sustainable film for packaging and electronics. While compared with pure cellulose nanopaper (CNP), it still exhibits relatively lower transparency or declining mechanical performance, which greatly hinders its practical application. To address these issues, we reported a highly available route involving a TEMPO-mediated oxidation method followed by a homogenization process to prepare lignin-containing cellulose nanofibers (LCNFs) based on a lignocellulose material and then directly processed the LCNFs into a dense film (LCNP) via a mature papermaking process. Due to small fibers produced by this method, the resultant LCNP exhibits an ultrahigh visible light transmittance (∼91%) close to CNP. Moreover, the high lignin reservation (∼16%) endows the nanopaper excellent UVA-blocking efficiency (∼68%) and better environmental durability than CNP. The retaining lignin was found to serve as a reinforcing agent filled in LCNP, resulting in a significant improvement on toughness, wet mechanical property, and thermal stability. Overall, this fully biobased LCNP with outstanding performance is a promising candidate to replace conventional petroleum-based materials in the fields like flexible electronics, packaging, and protective products.

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In this study, we present the synthesis, self-assembly, and enzyme responsive nature of a unique class of well-defined amphiphilic linear-dendritic block copolymers (PNVP-b-dendr(Phe-Lys)n, n = 1–3) based on linear poly(N-vinylpyrrolidone) (PNVP) and dendritic phenylalanyl-lysine (Phe-Lys) dipeptides. The copolymers were prepared via a combination ofreversible addition-fragmentation chain transfer (RAFT)/xanthates (MADIX) polymerization of N-vinylpyrrolidone and stepwise peptide chemistry. The results of fluorescence spectroscopy, 1H NMR analyses, transmission electron microscopy (TEM), and particle size analysis demonstrated that the copolymers self-assemble in aqueous solution into micellar nanocontainers that can disassemble and release encapsulated anticancer drug doxorubicin or hydrophobic dye Nile red by trigger of a serine protease trypsin under physiological conditions. The disassembly of the formed micelles and release rates of the drug or dye can be adjusted by changing the generation of dendrons in PNVP-b-dendr(Phe-Lys)n. Furthermore, the cytocompatibility of the copolymers have been confirmed using human lung epithelial cells (BEAS-2B) and human liver cancer cells (SMMC-7721). Due to the fact of their enzyme responsive properties and good biocompatibility, the copolymers may have potential applicability in smart controlled release systems capable of site-specific response.

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Petrochemical plastic accumulated on earth has caused a great threat to the ecological environment. Recently, the cellulose film has been one of the most attractive candidates to replace petroleum-based plastics owing to its favorable biodegradability, optical transparency, and resource abundance. However, the general strategies (including vacuum filtration, solution casting, etc.) to fabricate cellulose films are usually time-consuming and difficult to industrialize. Moreover, these films still suffer from inferior stability against water and poor mechanical strength in a humid environment, which is insufficient for practical applications. Herein, we report a facile and large-scale preparation strategy to manufacture high-performance cellulose bioplastic films composed of chemically and physically dual-crosslinked carboxymethylated cellulose fibers (CMFs). Moreover, the whole preparation time was within only 1 h, superior to the most reported method. In this process, bleached softwood kraft pulp was carboxymethylated to form a homogeneous negatively charged CMF slurry that can further crosslink with the polyamide epichlorohydrin resin or aluminum sulfate [Al2(SO4)3] via the strong electrostatic interaction. The resulting CMF-based bioplastic shows a high mechanical strength (158.2 MPa), excellent water stability, and improved wet strength (20.7 MPa). Furthermore, the CMF-based bioplastic also exhibits both high optical transparency (89.4%) and haze feature (77.9%), good thermal stability, and easy recyclability by mechanical disintegration. This fast, scalable, and low-cost strategy involving the simple papermaking process provides a promising industrialization route to produce a strong, recyclable, and sustainable cellulosic bioplastic that can potentially replace petrochemical plastics in engineering and packaging implications.