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The use of triboelectric nanogenerators to collect low-frequency mechanical energy has received widespread attention in recent years. Among these, single-electrode triboelectric nanogenerators have been studied for use as a power supply source for wearable electronic devices due to their simple and stable structure. The stability, hydrophobicity, and permeability under harsh environments are surely more pressing issues in the development and utilization of wearable devices. Herein, a superhydrophobic poly-(vinylidene fluoride) nanofiber membrane with built-in polydopamine-coated carbon cloth electrode was prepared using electrostatic spinning technology and spraying process to develop an all-fiber-based single electrode triboelectric nanogenerator (F-TENG). The results show that the triboelectric nanogenerator has an open-circuit voltage of up to 270 V, a short-circuit current of up to 80 μA, and a maximum power density of about 1.79 W/m2. The F-TENG can quickly recover the electrical energy output after being affected by water droplets and has an excellent sensing performance with stability during repeated water spraying. It was suggested that the prepared F-TENG with good air permeability, flexibility, superhydrophobicity, and self-cleaning capability can be used to power IoT devices exposed to harsh environments, thus making it a self-powered energy source for wearable electronic devices. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) as self-powered sensing devices have attracted extensive interest in the field of flexible wearable electronics. Endowing TENGs with excellent environmental adaptability and high sensitivity is considered to be one of the promising strategies to satisfy future intelligent electronic sensing devices. The interference of a humid environment and common bare electrode has been a great hindrance to the output performance of TENGs. In this paper, a core–shell superhydrophobic and flexible triboelectric nanogenerator (abbreviated as PP/AgH-TENG) was prepared based on a polydimethylsiloxane (PDMS) film surface modified with polytetrafluoroethylene (PTFE) particles as the triboelectric layer and AgNWs/PVA hydrogel as the electrode. The obtained PP/AgH-TENG (4 × 4 cm2 area) can easily light about 360 commercial LED lights with a maximum power density of 3.07 W/m2 by tapping. It is important that PP/AgH-TENG can overcome the effect of water molecules on charge transfer in a humid environment and quickly recover and maintain a high output. In addition, the bracelet made of PP/AgH-TENG can collect the mechanical energy generated by human movement, and these output performance curves clearly reflect the state of human movement. This research has great application potential in the field of intelligent wearable self-powered sensing. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) has been demonstrated as a sustainable energy utilization method for waste mechanical energy and self-powered system. However, the charge dissipation of frictional layer materials in a humid environment severely limits their stable energy supply. In this work, a new method is reported for preparing polymer film as a hydrophobic negative friction material by solution blending poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) and polyvinyl chloride (PVC), doping with titanium dioxide (TiO 2 ) nanoparticles, and further surface patterning modification. The P-TENG composed of the PVDF-HFP/PVC/TiO 2 composite film with optimized hydrophobic performance (WCA = 124°) achieved an output voltage of 235 V and a short-circuit current of 35 μA, which is approximately three times that of the bare PVDF-HFP-based TENG. Under charge excitation, the transferred charge of the P-TENG can reach 35 nC. When the external load resistance is 5.5 MΩ, the output peak power density can reach 1.4 W m -2 . Meanwhile, the hydrophobic surface layer with a rough surface structure enables the device to overcome the influence of water molecules on charge transfer in a humid environment, quickly recover, and maintain a high output. The P-TENG can effectively monitor finger flexibility and strength and realize real-time evaluation of the exercise state and hand fatigue of the elderly and rehabilitation trainers. It has broad application prospects in self-powered intelligent motion sensing, soft robotics, human-machine interaction, and other fields.

Transforming glyoxal to value-added glyoxylic acid (GA) is highly desirable but challenging due to the uncontrollable over-oxidation. In this work, we report on a first demonstration of semi-oxidation of glyoxal with high selectivity (86.5%) and activity on WO 3 nanoplate photoanode through the photoelectrochemical strategy. The optimization of reactivity was achieved via crystal facet regulation, showing a satisfactory GA production rate of 308.4 mmol m -2 h -2 , 84.0% faradaic efficiency, and 4.3% total solar-to-glyoxylic acid efficiency on WO 3 with enriched {200} facets at 1.6 V versus RHE. WO 3 with a high {200} facet ratio exhibits more efficient electron-hole transfer kinetics, resulting in the facilitated formation of hydroxyl radicals ( • OH) and glyoxal radicals. Meanwhile, the theoretical calculation results indicate that the high selectivity and activity come from the strong adsorption ability for glyoxal and the low reaction energy for glyoxal radical generation on the (200) facets of WO 3 . Moreover, the high energy demand toward oxalic acid production on WO 3 leads to the exciting semi-oxidation process.

Due to its inherently stronger hydration, Li + faces a higher dehydration energy than Na + at the entrance of the 8×(WL) 4 /POPE-CPNT. Present MD simulations show that it can enter the channel from a NaCl/LiCl solution only under an electric field stronger than 0.3 V nm -1 , while Na + is easier to move into the channel, which is well elucidated by two cations' PMF profiles. The cation-O w radial distribution functions, the electrostatic interactions with water, and the orientations of neighboring water all refer to a more compact solvation structure and stronger hydration of Li + . Regardless of whether there is an external electric field, Na + mainly appears in an α-plane zone, while Li + does so in a midplane region. The increase in the electric field strength significantly accelerates the cations' axial diffusions, shortening the residence times of two cations in the channel. Furthermore, it makes channel water tend to take positive dipole states.

As the starting material, kaolin is selectively and diversely fabricated to the superhydrophobic, superoleophobic-superhydrophilic, and superamphiphobic materials, respectively. The wettability of the kaolin surface can be selectively controlled and regulated to different superwetting states by choosing the corresponding modification reagent. The procedure is facile to operate, and no special technique or equipment is required. In addition, the procedure is cost-effective and time-saving and the obtained super-repellent properties are very stable. The X-ray photoelectron spectroscopy analysis demonstrates different changes of kaolin particles surfaces which are responsible for the different super-repellency. The scanning electron microscopy displays geometric micro- and nanometer structures of the obtained three kinds of super-repellent materials. The results show that kaolin has good applications in many kinds of superwetting materials. The method demonstrated in this paper provides a new strategy for regulating and controlling the wettability of solid surfaces selectively, diversely, and comprehensively.

A rare Ru-catalyzed highly selective synthesis of 3,4-dihydroisoquinolines or isoquinolines is accomplished via a redox-divergent hydrogen-retentive or hydrogen-releasing fashion. Notably, high cis-selectivity of 3,4-dihydroisoquinolines is achieved. Potential applications are shown by gram-scale reactions and very concise synthesis of N-containing polycyclic aromatic compounds. Primary mechanistic investigations indicate that the sequence of the major pathway involves Ru-catalyzed C-H activation, alkyne insertion, and subsequent 6π-electrocyclization.

Superhydrophobic surfaces were successfully prepared on Ti/Si substrates via the fabrication of conductive polyaniline (PANI) nanowire film. The PANI nanowire film was synthesized by electrodeposition of aniline into the pores of an anodic aluminum oxide (AAO) template on Ti/Si substrate followed by the removal of the template. The surface showed conductivity and superhydrophobicity, even in many corrosive solutions, such as acidic or basic solutions over a wide pH range. Field emission scanning electron microscopy (FE-SEM) demonstrated that the binary geometric structures at micro- and nanometer scale bestowed the prerequisite roughness on the surfaces. The chemical surface modification made the PANI nanowire film superhydrophobic. The results demonstrated that the PANI nanowire film will have good potential applications in the preparation of conductive superhydrophobic surfaces.

An amide-containing stratified self-assembled film is grafted on a silicon surface by a simple two-step method. First, N-[3-(trimethoxylsilyl)propyl]ethylenediamine (DA) molecules are self-assembled on silicon surfaces followed by deriving with stearoyl chloride (STC) through a surface coupling reaction. The films are characterized by means of contact angle measurement, ellipsometry, and attenuated total reflectance Fourier transformed infrared (ATR-FTIR) spectra. STC forms an ordered and hydrophobic film over the DA layer with a water contact angle of nearly 110 degrees. A microtribological study of the films is carried out on an atomic force microscope (AFM), and the wear-resistant property is tested on a ball-on-plate tribometer. Compared to the films in our previous study, the friction-reducing and load-affording abilities of the film are greatly improved. We contribute the improvements to the existence of two layers of hydrogen bonds, which can enhance the stability of the film by double in-plane cross-linking.