Interfaces between a liquid and a solid (L-S) are the most important surface science in chemistry, catalysis, energy, and even biology. Formation of an electric double layer (EDL) at the L-S ...interface has been attributed due to the adsorption of a layer of ions at the solid surface, which causes the ions in the liquid to redistribute. Although the existence of a layer of charges on a solid surface is always assumed, the origin of the charges is not extensively explored. Recent studies of contact electrification (CE) between a liquid and a solid suggest that electron transfer plays a dominant role at the initial stage for forming the charge layer at the L-S interface. Here, we review the recent works about electron transfer in liquid-solid CE, including scenerios such as liquid-insulator, liquid-semiconductor, and liquid-metal. Formation of the EDL is revisited considering the existence of electron transfer at the L-S interface. Furthermore, the triboelectric nanogenerator (TENG) technique based on the liquid-solid CE is introduced, which can be used not only for harvesting mechanical energy from a liquid but also as a probe for probing the charge transfer at liquid-solid interfaces.
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IJS, KILJ, NUK, PNG, UL, UM
Polymers are commonly used to fabricate triboelectric nanogenerators (TENGs). Here, several polymer films with similar main chains but different functional groups on the side chain are employed to ...clarify the contributions of each functional group to contact electrification (CE). The results show that the electron‐withdrawing (EW) ability and density of these functional groups on the main chain can determine both the polarity and density of CE‐induced surface charges. Similar results are obtained for CE in both the polymer–polymer and polymer–liquid modes. A theoretical mechanism involving electron cloud overlap is proposed to explain all of these results. More importantly, the unsaturated groups on poly(tetrafluoroethylene) molecular chain are proved to have a much stronger EW ability than the saturated groups. The density of these unsaturated groups can be increased using a sputtering technique, suggesting that this is a facile and effective method of enhancing the performance of TENGs. These results clarify the correlation between the molecular structure and macroscopic electrification behavior of polymers.
A series of polymer films with different functional groups on the side chain are employed for clarifying the contribution of functional groups to their contact electrification (CE) processes with both solids and liquids. The unsaturated groups of PTFE can enhance the electronegativity of the whole functional group.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Based on neo‐institutional theory, this paper examines whether social trust can influence corporate social responsibility (CSR). Using a sample of 4,209 observations selected from 788 firms listed in ...China between 2008 and 2015 and adopting an ordinary least square regression, we provide strong empirical evidence showing that social trust is positively associated with CSR. The result supports the view that social trust, as a kind of socially normative force, helps corporate managers safeguard stakeholders' interests by engaging in socially responsible activities. Our result holds after applying a series of robustness tests. We further find the positive relationship between social trust and CSR is more pronounced for state‐owned companies. This paper is one of the first to focus on and examine the relationship between social trust and CSR, and the findings contribute to our understanding of the determinants of CSR and highlight the influential role of social trust in improving CSR.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Metal–organic frameworks (MOFs), built from organic linkers and metal ions/clusters, have emerged as highly promising materials for wide applications. Combining highly porous crystalline MOFs with ...the surface‐enhanced Raman scattering (SERS) technique can achieve unprecedented advantages of high selectivity, high sensitivity, and expedience in analysis and detection. In this critical review, the aim is to present a comprehensive review of recent advances in understanding of the roles of MOFs in MOF‐SERS systems, particularly their structure‐to‐property correlation. Key examples are selected from representative literature to illustrate critical concepts and the MOF‐based property‐dependent applications are particularly emphasized. Finally, the barriers, future trends, and prospects for further advances in MOF‐SERS platforms are also discussed.
Combining highly porous crystalline metal–organic frameworks (MOFs) with the surface‐enhanced Raman scattering (SERS) technique can achieve unprecedented advantages of high selectivity, high sensitivity, and expedience in analysis and detection. Herein, recent advances in research on the roles of MOFs in MOF‐SERS systems, particularly their structure‐to‐property correlation, are systematically highlighted.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Rheumatoid arthritis is a common chronic inflammatory disorder and a major cause of disability. Despite the progress made with recent clinical use of anti-cytokine biologics, the response rate of ...rheumatoid arthritis treatment remains unsatisfactory, owing largely to the complexity of cytokine interactions and the multiplicity of cytokine targets. Here, we show a nanoparticle-based broad-spectrum anti-inflammatory strategy for rheumatoid arthritis management. By fusing neutrophil membrane onto polymeric cores, we prepare neutrophil membrane-coated nanoparticles that inherit the antigenic exterior and associated membrane functions of the source cells, which makes them ideal decoys of neutrophil-targeted biological molecules. It is shown that these nanoparticles can neutralize proinflammatory cytokines, suppress synovial inflammation, target deep into the cartilage matrix, and provide strong chondroprotection against joint damage. In a mouse model of collagen-induced arthritis and a human transgenic mouse model of arthritis, the neutrophil membrane-coated nanoparticles show significant therapeutic efficacy by ameliorating joint damage and suppressing overall arthritis severity.
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IJS, NUK, SBMB, UL, UM, UPUK
As a well‐known phenomenon, contact electrification (CE) has been studied for decades. Although recent studies have proven that CE between two solids is primarily due to electron transfer, the ...mechanism for CE between liquid and solid remains controversial. The CE process between different liquids and polytetrafluoroethylene (PTFE) film is systematically studied to clarify the electrification mechanism of the solid–liquid interface. The CE between deionized water and PTFE can produce a surface charges density in the scale of 1 nC cm−2, which is ten times higher than the calculation based on the pure ion‐transfer model. Hence, electron transfer is likely the dominating effect for this liquid–solid electrification process. Meanwhile, as ion concentration increases, the ion adsorption on the PTFE hinders electron transfer and results in the suppression of the transferred charge amount. Furthermore, there is an obvious charge transfer between oil and PTFE, which further confirms the presence of electron transfer between liquid and solid, simply because there are no ions in oil droplets. It is demonstrated that electron transfer plays the dominant role during CE between liquids and solids, which directly impacts the traditional understanding of the formation of an electric double layer (EDL) at a liquid–solid interface in physical chemistry.
The mechanism behind the contact electrification between liquid and solid remains controversial. According to experimental results and theoretical calculations, the contact electrification of ionic liquids and solids is caused by both electron transfer and ion transfer. Furthermore, the contact electrification between nonionic liquids and solids is mainly due to electron transfer.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Triboelectric nanogenerators are an energy harvesting technology that relies on the coupling effects of contact electrification and electrostatic induction between two solids or a liquid and a solid. ...Here, we present a triboelectric nanogenerator that can work based on the interaction between two pure liquids. A liquid-liquid triboelectric nanogenerator is achieved by passing a liquid droplet through a freely suspended liquid membrane. We investigate two kinds of liquid membranes: a grounded membrane and a pre-charged membrane. The falling of a droplet (about 40 μL) can generate a peak power of 137.4 nW by passing through a pre-charged membrane. Moreover, this membrane electrode can also remove and collect electrostatic charges from solid objects, indicating a permeable sensor or charge filter for electronic applications. The liquid-liquid triboelectric nanogenerator can harvest mechanical energy without changing the object motion and it can work for many targets, including raindrops, irrigation currents, microfluidics, and tiny particles.
Transformer-based methods have shown impressive performance in low-level vision tasks, such as image super-resolution. However, we find that these networks can only utilize a limited spatial range of ...input information through attribution analysis. This implies that the potential of Transformer is still not fully exploited in existing networks. In order to activate more input pixels for better reconstruction, we propose a novel Hybrid Attention Transformer (HAT). It combines both channel attention and window-based self-attention schemes, thus making use of their complementary advantages of being able to utilize global statistics and strong local fitting capability. Moreover, to better aggregate the cross-window information, we introduce an overlapping cross-attention module to enhance the interaction between neighboring window features. In the training stage, we additionally adopt a same-task pre-training strategy to exploit the potential of the model for further improvement. Extensive experiments show the effectiveness of the proposed modules, and we further scale up the model to demonstrate that the performance of this task can be greatly improved. Our overall method significantly outperforms the state-of-the-art methods by more than 1dB.
Triboelectric materials and their modification methods are the cornerstones for fabricating triboelectric nanogenerators (TENGs). Numerous modification methods have been proposed for TENGs, while a ...highly effective and long-term stable method is still under exploration. Here, a surface modification method using low-energy ion irradiation has been proposed for tuning the chemical structures and functional groups of triboelectric polymers at the molecular level. The low-energy ion irradiation brings negligible change to the surface roughness at the micro-scale and mechanical flexibility of the target polymer, while it can provide a stable modification of the electrification performance. Systematic studies about the chemical structure changes in four different polymers induced by ion irradiation can bring insight into the interaction between different chemical groups and electrification performance. A Kapton film modified by ion irradiation shows several unprecedented characteristics, such as high surface charge density, excellent stability and ultrahigh electron-donating capability, and not only creates a new record in the tribo series, but also provides a good demonstration for regulating electrification behavior based on controllable chemical structure change. This study can open up a series of possible breakthroughs in the production of triboelectric materials with diversified properties, which can promote the study of TENGs from a very fundamental level.
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