Search

Moisture-trigged electricity generator (MEG) that can convert ubiquitous moisture into electricity are highly desirable for developing renewable energy supply and ameliorating the crisis in energy. Constructing an asymmetric ordered, namely gradient ordered porous membrane has great potential in MEG. Herein, a series of cellulose acetate (CA)-based membranes with ordered asymmetric honeycomb membranes were fabricated by Breath Figure method, along with silver nanowires (AgNWs) coating. The asymmetric gradient honeycomb pores were achieved by graft modification of lauroyl chloride and adjustment of relative humidity, which not only endowed the MEG with sensitive sensing signals transport under tension and humidity fluctuations but also enhanced voltages generation speed under flowing moisture. The current study provides a facile and scalable strategy for constructing asymmetric gradient ordered porous materials and creates more possibilities for MEG self-powered flexible wearable electronic devices., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

An environmental-friendly lipase induced highly hydrophobic NFC film was fabricated through lipase induced dimethyl adipate (DA) esterification followed by silver nanowires (AgNWs) coating for strain sensor application. Due to the lipase activation, the substitution degree (DS NMR ) of 0.18 was achieved, which was three times higher than that of the control sample (without lipase treatment of NFC-DA). As a result, the water contact angle (WCA) of lipase induced adipated-NFC film was reached to 105 ± 3° from 50 ± 2.3° of NFC-DA. In addition, the cellulose structure and performance were well maintained after lipase induced esterification, confirmed by AFM, SEM, TG/DTG, and XRD analysis. After AgNWs coating and annealing, the hydrophobic NFC film-based strain sensor exhibited excellent sensitivity towards human motion, such as finger/wrist movement in real-time, even under wet conditions. Overall, a highly hydrophobic NFC film-based strain sensor was fabricated, which has promising application in wearable devices for human motion monitoring., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

To date, flexible pressure sensors built on silver nanowires (AgNWs) have attracted tremendous attention, owing to their versatile applications in wearable, human-interactive, health-monitoring devices. Cellulose and its derivatives, which show great promise in serving flexible pressure sensors as the desired substrate due to their natural abundance, biocompatibility, easy processibility, and low costs. Herein, we reported a rational strategy to design a silver nanowires-dual-cellulose conductive paper. Its morphology, chemical and crystal structures, thermal stability, mechanical performances, and electrical properties were carefully studied. The results suggested that good tensile properties (tensile strength ≤8.10 MPa), high electrical conductivity (≤ 1.74 × 10 4  S·m -1 ) with long-term stability, and good adhesion stability (bending cycles over 500) were obtained. Furthermore, the use of such conductive paper as substrate for versatile flexible pressure sensors was demonstrated, which exhibited fast response (~ 0.48 s) and high sensitivity, in response to finger motion, voice recognition, and human pulse, etc., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Constructing multifunctional electromagnetic interference (EMI) shielding films with superior mechanical strength has sparked a lot of interest in the fields of wearable electronics. In this work, the conductive silver nanowires (AgNWs) were synthesized and impregnated into the highly aligned cellulose scaffold (CS) fabricated by wood delignification followed by hot-pressing and polydimethylsiloxane (PDMS) dipping processes to obtain the outstanding EMI shielding cellulosic film (d-AgNWs@CS-PDMS). The consecutively conductive pathway of AgNWs was constructed in the microchannels of the CS as a result of the hydrogen bonding between AgNWs and cellulose fibers, which is conducive to the reflection of incident EM waves. The higher degree of nanofiber alignment and the compact conductive network were improved by densification upon hot pressing, which endows the composite film with striking mechanical properties (maximum tensile strength of 511.8 MPa) and superb EMI shielding performance (shielding effectiveness value of 46 dB with a filler content of 21.6 wt %) at the X band (8.2-12.4 GHz). Moreover, the existence of an intensive AgNWs network and the introduction of the PDMS layer improve the hydrophobicity and antibacterial activity of the composite film, avoiding serious health concerns in the long-term wearing. These results demonstrate that the obtained d-AgNWs@CS-PDMS composite film has high potential as an EMI shielding material used for wearable devices.

In this study, a series of conductive composite wires were successfully prepared by combining dispersions of multi-wall carbon nanotubes (MWCNTs) and TEMPO-oxidized cellulose nanofibers (TOCNFs) with different MWCNTs contents into a dispersion of partially deacetylated α-chitin nanofibers (α-DECHNs) followed with a drying process. The TOCNFs/MWCNTs/α-DECHNs composite wires were prepared by extruding the negatively charged TOCNFs/MWCNTs dispersion into the positively charged α-DECHNs dispersion. The contact of the positively charged α-DECHNs and the negatively charged TOCNFs/MWCNTs triggers the electrostatic interaction (heterocoagulation) resulting in wire-shaped conductive composites. The SEM analysis indicates this conductive composite material has a wire-like shape with a rough but tight surface. The properties of samples were characterized by a zeta potential analyzer (Zetasizer Nano), a four-probe, an electrochemical workstation, a Fourier transform infrared spectroscopy (FTIR), an X-ray diffractometer (XRD), and a thermogravimetric analyzer (TG). Besides, the conductivity and the AC impedance of TOCNFs/MWCNTs/α-DECHNs composite wires with different MWCNTs contents were also analyzed. The conductivity of the composite wire increases from 9.98 × 10 - 6  S∙cm - 1 to 1.56 × 10 - 3  S∙cm - 1 as the MWCNTs content raises from 3.0 wt% to 14.0 wt%. When the MWCNTs content reaches 14.0 wt%, the prepared composite wire can light up LED at a voltage of 5 V, indicating the great potential of this biomass-based conductive composite in conductive material application., (Copyright © 2019 Elsevier B.V. All rights reserved.)