5 research outputs found

    Rapid and Efficient Multiple Healing of Flexible Conductive Films by Near-Infrared Light Irradiation

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    Healable, electrically conductive films are essential for the fabrication of reliable electronic devices to reduce their replacement and maintenance costs. Here we report the fabrication of near-infrared (NIR) light-enabled healable, highly electrically conductive films by depositing silver nanowires (AgNWs) on polycaprolactone (PCL)/poly­(vinyl alcohol) (PVA) composite films. The bilayer film has sheet resistance as low as 0.25 Ω·sq<sup>–1</sup> and shows good flexibility to repeated bending/unbending treatments. Multiple healing of electrical conductivity lose caused by cuts of several tens of micrometers wide on the bilayer film can be conveniently achieved by irradiating the film with mild NIR light. The AgNW layer functions not only as an electrical conductor but also as a NIR light-induced heater to initiate the healing of PCL/PVA film, which then imparts its healability to the conductive AgNW layer

    Layer-by-Layer Assembly of Fluorine-Free Polyelectrolyte–Surfactant Complexes for the Fabrication of Self-Healing Superhydrophobic Films

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    Fluorine-free self-healing superhydrophobic films are of significance for practical applications because of their extended service life and cost-effective and eco-friendly preparation process. In this study, we report the fabrication of fluorine-free self-healing superhydrophobic films by layer-by-layer (LbL) assembly of poly­(sodium 4-styrenesulfonate) (PSS)–1-octadecylamine (ODA) complexes (PSS–ODA) and poly­(allylamine hydrochloride) (PAH)–sodium dodecyl sulfonate (SDS) (PAH–SDS) complexes. The wettability of the LbL-assembled PSS–ODA/PAH–SDS films depends on the film structure and can be tailored by changing the NaCl concentration in aqueous dispersions of PSS–ODA complexes and the number of film deposition cycles. The freshly prepared PSS–ODA/PAH–SDS film with micro- and nanoscaled hierarchical structures is hydrophilic and gradually changes to superhydrophobic in air because the polyelectrolyte-complexed ODA and SDS surfactants tend to migrate to the film surface to cover the film with hydrophobic alkyl chains to lower its surface energy. The large amount of ODA and SDS surfactants loaded in the superhydrophobic PSS–ODA/PAH–SDS films and the autonomic migration of these surfactants to the film surface endow the resultant superhydrophobic films with an excellent self-healing ability to restore the damaged superhydrophobicity. The self-healing superhydrophobic PSS–ODA/PAH–SDS films are mechanically robust and can be deposited on various flat and nonflat substrates. The LbL assembly of oppositely charged polyelectrolyte–surfactant complexes provides a new way for the fabrication of fluorine-free self-healing superhydrophobic films with satisfactory mechanical stability, enhanced reliability, and extended service life

    Highly Transparent, Nanofiller-Reinforced Scratch-Resistant Polymeric Composite Films Capable of Healing Scratches

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    Integration of healability and mechanical robustness is challenging in the fabrication of highly transparent films for applications as protectors in optical and displaying devices. Here we report the fabrication of healable, highly transparent and scratch-resistant polymeric composite films that can conveniently and repeatedly heal severe damage such as cuts of several tens of micrometers wide and deep. The film fabrication process involves layer-by-layer (LbL) assembly of a poly(acrylic acid) (PAA) blend and branched poly(ethylenimine) (bPEI) blend, where each blend contains the same polyelectrolytes of low and high molecular weights, followed by annealing the resulting PAA/bPEI films with aqueous salt solution and incorporation of CaCO<sub>3</sub> nanoparticles as nanofillers. The rearrangement of low-molecular-weight PAA and bPEI under aqueous salt annealing plays a critical role in eliminating film defects to produce optically highly transparent polyelectrolyte films. The in situ formation of tiny and well-dispersed CaCO<sub>3</sub> nanoparticles gives the resulting composite films enhanced scratch-resistance and also retains the healing ability of the PAA/bPEI matrix films. The reversibility of noncovalent interactions among the PAA, bPEI, and CaCO<sub>3</sub> nanoparticles and the facilitated migration of PAA and bPEI triggered by water enable healing of the structural damage and restoration of optical transparency of the PAA/bPEI films reinforced with CaCO<sub>3</sub> nanoparticles

    Faradaic Rectification in Electrochemical Deionization and Its Influence on Cyclic Stability

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    Capacitive deionization (CDI) is a typical configuration of electrochemical deionization, which suffers from severe desalination capacity degradation derived from uncontrolled parasitic reactions. In this work, Faradaic rectification, the phenomenon by which electrode potentials and side reactions are dynamically regulated due to the asymmetrical anode/cathode Faradaic reactions, was studied under various CDI operation conditions. It was found that the Faradaic rectification in CDI would lead to capacity degradation indirectly by accelerating carbon anode oxidation and would be influenced by the cell voltage, flow rate, and asymmetric electrode construction. We also found an unconventional degradation mechanism in Faradaic cathode hybrid-CDI (HCDI) caused by the dramatic electrode-potential redistribution, which is derived from Faradaic rectification rather than the electrode structure decay. By adding a cation-exchange membrane to block the dissolved oxygen from cathode, the Faradaic rectification was suppressed successfully, and thus, the cyclic performance of CDI and HCDI was significantly increased by 59 and 46%, respectively (in 100 h cycling). This study provides an insight into understanding the Faradaic rectification in electrochemical deionization and its influence on CDI/HCDI cyclic stability, which should be of value to future explore cost-competitive membrane-less electrochemical deionization construction


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    <p>Trichothecene mycotoxins, such as deoxynivalenol (DON) produced by the fungal pathogen, Fusarium graminearum, are not only important for plant infection but are also harmful to human and animal health. Trichothecene targets the ribosomal protein Rpl3 that is conserved in eukaryotes. Hence, a self-defense mechanism must exist in DON-producing fungi. It is reported that TRI (trichothecene biosynthesis) 101 and TRI12 are two genes responsible for self-defense against trichothecene toxins in Fusarium. In this study, however, we found that simultaneous disruption of TRI101 and TRI12 has no obvious influence on DON resistance upon exogenous DON treatment in F. graminearum, suggesting that other mechanisms may be involved in self-defense. By using RNA-seq, we identified 253 genes specifically induced in DON-treated cultures compared with samples from cultures treated or untreated with cycloheximide, a commonly used inhibitor of eukaryotic protein synthesis. We found that transporter genes are significantly enriched in this group of DON-induced genes. Of those genes, 15 encode major facilitator superfamily transporters likely involved in mycotoxin efflux. Significantly, we found that genes involved in the metabolism of gamma-aminobutyric acid (GABA), a known inducer of DON production in F. graminearum, are significantly enriched among the DON-induced genes. The GABA biosynthesis gene PROLINE UTILIZATION 2-2 (PUT2-2) is downregulated, while GABA degradation genes are upregulated at least twofold upon treatment with DON, resulting in decreased levels of GABA. Taken together, our results suggest that transporters influencing DON efflux are important for self-defense and that GABA mediates the balance of DON production and self-defense in F. graminearum.</p