High Wettability Research Articles

Strategies on Enabling High Areal Sulfur Loading in Lithium Sulfur Batteries

Needs for energy storage devices in modern-day applications such as electric vehicles and other high energy consuming portable electronics make the Lithium sulfur batteries (LSBs) to be one of the most attractive types since they offer a high theoretical energy density (2600 Wh kg-1), which is about an order of magnitude higher than the theoretical specific capacity of the lithium ion batteries. In addition, Sulfur is one of the most abundant materials in nature and moreover, a non-toxic element which makes the lithium sulfur battery a suitable candidate for commercialization. However, obstacles to overcome include the loss of active sulfur due to various phenomena mainly represented by polysulfide diffusion and reactivity on the lithium anode. Another serious issue observed in so many ways is the low electronic conductivity of Sulfur and its products such as Li2S as a result of cycling. These problems are often exacerbated at higher sulfur loading and lower electrolyte to sulfur ratios (E/S). One way to increase the sulfur loading is to increase the thickness of the cathode which in return increases the risk of low utilization of active material because of the high thickness and low wettability by electrolyte. Another way is to increases the ratio of the sulfur in respect to conductive host material without increasing the thickness of the cathode. By doing so, sulfur is going to fill all the pores existing in the host material and therefore, this structure cannot provide enough volume expansion during discharge process and as a result, the cathode structure may collapse and the whole cell fail. Therefore, to come up with a high performance and stable battery during cycling, there is no doubt that we have to focus on the structure of the cathode and the host material to effectively confine the sulfur and produced polysulfide and at the same time, alleviate the way of the electron transfer through the conductive network.In this research, we investigate some of the most influential parameters mainly associated with the morphology of the cathode to improve capacity retention. Optimizing the sulfur loading, E/S content, pore structure and pore volume, and the thickness of the cathode lead to an overarching understanding of the physical transitions that occur during the discharge and charge operation of the battery. In addition, various electrochemical testing to evaluation the loss of activity of the cathode surface is also carried it to correlate to the proposed physical model.

Lithium Metal Anode Using Fluorination on Iron Powder for Lithium Metal Batteries

High-energy-density batteries have been gaining considerable attentions in renewable energy, and Li metal anodes are potential candidates for developing such batteries. Therefore, many attempts were carried out to find alternative ways to use Li by mixing it with tiny metal powders or impregnating the porous media. However, most materials used in battery fabrication are lithiophobic to molten Li; hence, infusion of Li into porous structures or powders with an intrinsically lithiophobic surface presents challenges in developing Li metal batteries. Optimizing and improving molten Li's wettability is one approach to address this. Herein, we propose an efficient and straightforward direct fluorination method for achieving an ultra-lithiophilic fluoride layer on the surface of the Fe powder. Fluorination of Fe powders resulted in a remarkable increase in the wettability of molten Li by a growth of Fe-F layer on the surface of Fe powder. This layer was lithiophilic and showed high wettability. Moreover, an anode prepared using fluorinated Fe-Li metal showed no evidence of short circuits or dendrite formation after the cycle test at 0.1 and 0.2 mA cm-2. In contrast, a pure Li anode and pristine Fe powder showed unstable charge-discharge characteristics in cycle tests. The proposed fluorination is the most practical and straightforward method among those reported. Thus, the proposed method will further develop rechargeable lithium-metal battery technology.

Design of Surfaces with Persistent Antimicrobial Properties on Stainless Steel Developed Using Femtosecond Laser Texturing for Application in "High Traffic" Objects.

Metal-based high-touch surfaces used for diverse applications in everyday use, like handrails, playground grab handles, doorknobs, ATM touch pads, and desks, are the most common targets for pollution with a variety of microbes; there is thus a need to improve their antimicrobial properties, an issue which has become a challenge in recent years, particularly after the COVID-19 pandemic. According to the World Health Organization (WHO), drug-resistant pathogens are one of the main concerns to global health today, as they lead to longer hospital stays and increased medical costs. Generally, the development of antimicrobial surfaces is related to the utilization of chemical methods via deposition on surfaces in the forms of various types of coatings. However, the addition of chemical substances onto a surface can induce unwanted effects, since it causes surface chemistry changes and, in some cases, cannot provide long-lasting results. A novel approach of utilising ultra-short laser radiation for the treatment of metallic surfaces by inducing a variety of micro- and nanostructuration is elaborated upon in the current research, estimating the optimum relation between the wettability and roughness characteristics for the creation of antimicrobial properties for such high-touch surfaces. In the current study, AISI 304-304L stainless steel metal was used as a benchmark material. Surface texturing via laser ablation with femtosecond laser pulses is an effective method, since it enables the formation of a variety of surface patterns, along with the creation of bimodal roughness, in one-step processing. In this investigation, a precise approach toward developing hydrophobic stainless steel surfaces with tunable adherence using femtosecond laser-induced modification is described. The impact of basic femtosecond laser processing parameters, like the scanning velocity, laser energy, and wettability properties of the laser-processed stainless steel samples, are examined. It is identified that the topography and morphology of laser-induced surface structures can be efficiently changed by adapting the laser processing parameters to create structures, which facilitate the transfer of surface properties from extremely low to high surface wettability.

Bacterial cellulose composite aerogel with high elasticity and adjustable wettability for dye absorption and oil–water separation

Recently, cellulose-based biomass aerogel, as a high performance adsorption material, has received considerable attention. However, it remains a huge challenge to prepare cellulose aerogels with outstanding mechanical properties by simple and environmentally-friendly strategies. Here, we describe a green one-pot method to prepare a versatile bacterial cellulose/γ-(2,3-epoxypropoxy) propytrimethoxysilane trimethoxysilane composite aerogel (BK aerogel). The elasticity of BK aerogel is significantly improved and up to 96.4% after compression under 80% strain. Further, the elastic recovery can reach 87.8% over 50 times compressions at a set strain of 80 %, implying the obtained composite aerogel possesses strong fatigue resistance. BK aerogel could be soaked in water to adsorb cationic dyes and reused without being damaged. In addition, the prepared BK aerogel is rich in hydroxyl and epoxy groups, so its surface chemistry can be further adjusted. Taking hydrophobic modification as an example, the prepared aerogel can be used for oil–water separation and reused by mechanical squeezing. This study paves a simple and green solution for developing high elastic cellulose nanofiber aerogel with adjustable surface chemistry to meet diverse applications.

SiO2/SiC Nanowire Surfaces as a Candidate Biomaterial for Bone Regeneration

Tissue engineering (TE) and nanomedicine require devices with hydrophilic surfaces to better interact with the biological environment. This work presents a study on the wettability of cubic silicon-carbide-based (SiC) surfaces. We developed four cubic silicon-carbide-based epitaxial layers and three nanowire (NW) substrates. Sample morphologies were analyzed, and their wettabilities were quantified before and after a hydrogen plasma treatment to remove impurities due to growth residues and enhance hydrophilicity. Moreover, sample biocompatibility has been assessed with regard to L929 cells. Our results showed that core–shell nanowires (SiO2/SiC NWs), with and without hydrogen plasma treatment, are the most suitable candidate material for biological applications due to their high wettability that is not influenced by specific treatments. Biological tests underlined the non-toxicity of the developed biomaterials with regard to murine fibroblasts, and the proliferation assay highlighted the efficacy of all the surfaces with regard to murine osteoblasts. In conclusion, SiO2/SiC NWs offer a suitable substrate to develop platforms and membranes useful for biomedical applications in tissue engineering due to their peculiar characteristics.

Interfacial engineering of MXene-based composite aerogel for high-performance, multifunctional solar steam generator

MXene, an emerging two-dimensional material, has shown its evident application prospects in solar-driven interfacial water evaporation due to excellent photothermal conversion capability. However, MXene still suffers from a few undesirable characteristics in this scenario, including weak stability, self-stacking, and suboptimal optical absorption. To address these issues, in this paper, we fabricated a MXene-based composite aerogel, featuring with interconnected porous structure, broad and high solar absorption, good wettability and photothermal capacity. As our judicious structural and compositional design for the aerogel decreased the evaporation enthalpy of water, the solar steam generator based on the aerogel exhibited an outstanding water evaporation rate as high as 2.31 kg m−2 h−1 under one sun irradiation (and the corresponding solar-to-vapor conversion efficiency reached 90.8 %). Additionally, the aerogel was also designed with an excellent adsorption capacity for removal of heavy metal ions from water as well as a good antibacterial ability, which should be helpful in dealing with the complex working environments for solar steam generators. This work may shed light on the design and development of multifunctional solar steam generators toward practical and sustainable applications.

The critical role of fracture flow on two-phase matrix–fracture transfer mechanisms

We analyze the dynamics of imbibition in a fractured medium using the Direct Numerical Simulation of the Navier–Stokes equations. Pore geometries with homogeneous and heterogeneous pore distributions at the matrix and fracture interface are considered in this study. We evaluate the role of critical factors such as wettability, viscosity ratio, injection rate, and the magnitude of the interfacial tension on the pore-scale dynamic of mass exchange between matrix and fracture for 2D geometries consisting of a complex pore-geometry and a single fracture. Two different regimes are identified during the injection of wetting fluid through the fracture into the domain saturated with a non-wetting fluid: (1) co-operative (co-current) imbibition before the wetting phase breakthrough and, (2) counter-current imbibition follows afterwards. For the studied 2D geometries, the displacement efficiency is higher in the co-operative imbibition, while the counter-current imbibition occurs at a slow pace. Lower injection rates in the fracture are in favor of improving displacement efficiency in the porous matrix. Higher wettability and interfacial tension help the wetting fluid to penetrate further into the matrix and improve the displacement rate for both co-operative and counter-current modes of displacement.

Temperature Resistance Properties of Unidirectional Laminated Cf/SiC-Al Prepared by PIP and Vacuum Pressure Infiltration.

Material used for aero-engine fan blade requires excellent mechanical properties at high temperature (300 °C). Continuous carbon-fiber-reinforced silicon carbide ceramic matrix composites (Cf/SiC) are necessary candidates in this field, possessing low density, high strength, high modulus, and excellent high-temperature resistance. However, during the preparation process of Cf/SiC, there were inevitably residual pores and defects inside, resulting in insufficient compressive strength and reliability. The vacuum pressure melting infiltration process was used to infiltrate low melting point and high wettability aluminum alloys into the porous Cf/SiC composite material prepared by the precursor impregnation cracking process, repairing the residual pore defects inside the body. The porosity of porous Cf/SiC decreased from 49.65% to 5.1% after aluminum alloy repair and strengthening. The mechanical properties of Cf/SiC-Al composite materials strengthened by aluminum alloy repair after heat treatment were studied. The tensile strength of the as-prepared Cf/SiC-Al was 166 ± 10 MPa, which were degraded by 13~22% after heat treatment. The nonlinear sections of stress-displacement curve of as-treated samples were shorter than that of as-prepared sample. The hardness of aluminum alloy matrix after 300 °C 1 h heat treatment was 58 Hv, which was not obviously reduced compared with the sample without heat treatment. The vacuum infiltration of aluminum alloy is expected to have guiding significance for repairing and strengthening internal defects in ceramic matrix composites.

Effect of TaC on microstructure and mechanical properties of 316L stainless steel by selective laser melting

Selective laser melting (SLM) is a rapid processing technology used to directly manufacture metal terminal components. TaC is often utilized to enhance mechanical properties of metal due to its excellent performance. In this study, SLM was employed to manufacture TaC/316 L composites with varying TaC volume content. The effect of TaC content on the microscopic appearance and mechanical properties of SLM-316 L stainless steel was then explored. The TaC admixture was efficiently and effectively distributed on 316 L powder particle surfaces using short-duration high energy ball milling. Under the optimal parameters for SLM, the relative densities of the specimens reached over 99.0% because of the high wettability of 316 L with TaC. Moreover, grain refinement was observed after microstructural analysis due to interactions between the TaC and 316 L. Tensile, Charpy impact, and microhardness tests demonstrated that the adjunction of 0.5 vol% and 1.5 vol% TaC provided a significantly enhanced yield strength (increased by 7.4% and 30.9%), ultimate tensile strength (increased by 5.6% and 27.1%), and microhardness (increased by 9.9% and 22.7%). The impact toughness (reduced by 20.3% and 51.4%) and ductility (reduced by 23.1% and 39.5%) were maintained.

Coupled bubble dynamics and interaction mechanisms of adjacently nucleated vapor bubbles under subcooled pool boiling regime

The present work investigates the plausible modes of interaction between two adjacently located vapor bubbles growing on high wettability surface during subcooled nucleate pool boiling. The study becomes important as the phenomenon of bubble interaction has a significant impact on the resulting bubble dynamic parameters as well as on microlayer dynamics of the respective vapor bubbles. As against the symmetric growth of microlayer in the case of isolated pool boiling, microlayers of mutually interacting vapor bubbles no longer remain symmetric and tend to deplete relatively faster, thereby influencing the resulting wall heat transfer rates. Toward this, the microlayers and dynamics of adjacently located interacting vapor bubbles have been mapped in a simultaneous manner using thin-film interferometry and high-speed rainbow schlieren deflectometry as a function of varying subcooling levels. Results of the experiments revealed that parameters such as non-dimensional spacing between the two vapor bubbles, supplied heat flux, and degree of subcooling have a strong impact on the mechanism of bubbles' interaction, which, in turn, influence the bubble departure frequency, bubble diameter, and microlayer dynamics. Three dominant modes of bubble interaction, hydrodynamic interaction (HI), thermal interaction (TI), and coalescence (C), were identified as a function of the level of subcooling. Quantification of the experimental data showed that the equivalent diameter of the vapor bubble increases with an increase in the level of heat flux, while it decreases with an increase in the subcooling level. Additionally, the secondary nucleation affects the liftoff time and movement of the primary bubble and can hydrodynamically deplete the microlayer of the first bubble even when the bubbles are far apart, with the depletion rates showing a strong dependence on the growth rate and location of the secondary nucleation.

In-situ fabricated copper-holmium co-doped cobalt ferrite nanocomposite with cross-linked graphene as novel electrode material for supercapacitor application

Recently, hybrid electrode materials based on cross-linked carbon analogues have gained significant consideration for their excellent cyclic stability and high specific capacities. This work presents the fabrication of copper and holmium co-doped cobalt ferrite with cross-linked graphene (denoted as CH-CoF/CLG) through one-step hydrothermal route, as novel electrode material for supercapacitor study. The electrochemical performance of CH-CoF/CLG along with its counterparts i.e., CoF, CH-CoF was evaluated through CV, GCD, and EIS analysis using three electrode system. The specific capacitance (Csp) of CoF, CH-CoF, and CH-CoF/CLG nanocomposite at a sweep rate of 5 mV/s is 458 F/g, 762 F/g, and 1258 F/g, respectively, within a potential range of 0.0 to 0.6 V. For CH-CoF/CLG, the calculated slope value (b = 0.84) using power law showed that the energy storage mechanism is based on both capacitive and diffusional processes. The GCD test showed that CH-CoF/CLG exhibited long discharge time (td = 615 s), as compared to CH-CoF (td = 409 s), and CoF (td = 264 s). Moreover, after the fabrication of CH-CoF with CLG, the value of equivalent series resistance (ESR) and charge transfer resistance (Rct) for CH-CoF/CLG were decreased to 0.74 Ω and 0.84 Ω, compared to CoF (1.18 Ω and 1.29 Ω) and CH-CoF (0.88 Ω and 1.0 Ω). When tested for cyclic stability, CH-CoF/CLG displayed insignificant loss in performance up to 3000 cyclic runs. The high supercapacitor performance of CH-CoF/CLG can be assigned to the combined effects arising from the co-doping of transition metal and rare earth metal ions (Cu+2 and Ho+3) into CoF lattice, porous cross-linked structure, high wettability, low intrinsic resistance, and easy accessibility of KOH ions into deep layers of active material. As obtained results deduce that the CH-CoF/CLG nanocomposite is a competent capacitive material for energy storage.

Gas exfoliation induced N, S-doped porous 2D carbon nanosheets for effective removal of copper ions by capacitive deionization

Using capacitive deionization to remove heavy metal ions from water has received much attention, but the inferior salt adsorption capacity (SAC) of electrode materials has always limited its practical application. Herein, N, S co-doped two-dimensional (2D) porous glucose derived carbon nanosheets (NSPGC) was successfully fabricated, utilizing the gas exfoliation by calcination of thiourea. The NSPGC demonstrates distinct 2D lamellas, high specific surface area (2529 m2 g−1), hierarchical pore structure and high wettability. In electrochemical tests, a high specific capacitance (127 F g−1) and electrons/ions transport performance can be achieved in the NSPGC, moreover it showed a prominent SAC of 206.57 mg g−1 and recoverability in 100 mg L−1 CuSO4 solution. Moreover, the density functional theory (DFT) calculation manifested the intrinsic affinity of Cu2+ improved by N, S co-doping, which played an essential role in enhancing the Cu2+ removal performance of CDI. Our work provided a new insight into the preparation of high-performance CDI electrode materials for Cu2+ removal and promoted the application of CDI in heavy metal wastewater.

Electrospun heterocycle aramid nanofiber separator with MOF-supported porous structure enabled excellent cycling stability for lithium metal batteries with high LiFePO4 loading

Recently, para-aramid nanofiber separators have attracted more attention in lithium metal batteries (LMBs); however, the balance between safety and electrochemical performance remains challenging. Herein, a robust, porous, and thermotolerant separator (ZPBIA) is proposed based on electrospun heterocycle aramid nanofibers and in-situ grown metal-organic framework (MOF). First, introducing H2SO4 enables improved electrospinnability of rigid-chain poly(p-phenylene -benzimidazole-terephthalate) (PBIA) due to hierarchical hydrogen bonds crosslinking network formation. Next, zeolitic imidazolate framework-67 (ZIF-67) nanosheets anchored in situ on PBIA nanofibers confer high porosity (91%) and good electrolyte wettability to the ZPBIA separator. As a result, the assembled LFP/ZPBIA/Li cell with a high LiFePO4 (LFP) loading (12 mg cm−2) delivers excellent rate capacity at 5.0 C (76 mAh g−1) and impressive long-term cycling stability at 1.0 C (a minor capacity decay of 0.031% per cycle after 500 cycles). Benefiting from the intrinsic properties of PBIA, the ZPBIA separator possesses high mechanical strength to prevent Li dendrites puncture. Moreover, the open circuit voltage stabilizes at ∼3.4 V from 30 to 150 ℃ for LFP/ZPBIA/Li cell, which is probably applied in high-temperature conditions. This work provides a novel fabrication of functional separators to balance the safety and electrochemical property of LMBs.

Superhydrophobic DTES-SEP/SiO2@PDMS coated sponge and stainless steel mesh for efficient oil and water separation

The exploitation of offshore oil will inevitably cause oil leakage, which not only affects the ecological environment but also threatens the balance of the marine ecosystem. Therefore, new materials for efficient oil-water separation need to be continuously researched. In this paper, dodecyltriethoxysilane (DTES) was used to hydrophobically modify meerschaolite (SEP) and silicon dioxide (SiO2) nanoparticles. DTES-SEP/SiO2@PDMS coatings were successfully prepared on the surface of sponges and stainless steel meshes by immersion in the presence of polydimethylsiloxane (PDMS). The coating has a water contact angle of up to 153°. It exhibits high wettability. It is worth noting that the adsorption capacity of coated sponges to various oils and organic solvents is 27–77 times their own weight. More importantly, the prepared coatings exhibit excellent stability in strong corrosive solutions. In addition, the mechanical properties of DTES-SEP/SiO2@PDMS coating remain stable after abrasion and peeling. At the same time, the coating shows excellent resistance to grit, methylene blue solution and clay. This research provides a reliable way to achieve efficient oil-water separation.

In situ aluminide armored polyimide nanofiber separators with ultrahigh strength and high wettability for advanced lithium-ion batteries

Polyimide (PI) has been widely used in aerospace, electronic information, novel energy, and other industries due to its excellent high- and low-temperature, radiation, and chemical corrosion resistance. However, the use of electrospun PI separators in lithium-ion batteries (LIBs) is limited due to their poor electrolyte wettability and insufficient mechanical strength. Inorganic materials such as aluminide have typically been used in the coating composition of PI separators. To investigate the effects of different aluminide components, in this work, PI materials were prepared by the complexation–hydrolysis method and used as separators for LIBs. The physicochemical and electrochemical properties of the different nanofiber membranes were studied by adjusting the calcination temperature. The results showed that the sample with the highest tensile strength was 107.6 MPa, which is close to the commercial polyolefin separator. When the calcination temperature increased to 300 °C and then exceeded 400 °C, the aluminide shell initially transformed into thin boehmite and then into γ-Al2O3 phases. The mechanical properties of the nanofiber membranes were enhanced, and the wettability and electrochemical characteristics also improved to some extent. Furthermore, the nanofiber structure was destroyed at 500 °C and could not meet the long-term battery cycles. Therefore, when the calcination temperature was controlled between 300 °C and 400 °C, the aluminide-armored PI nanofiber membranes exhibited better comprehensive performance and were suitable for use as separators in LIBs, which was of great significance for improving the safety and stability of LIBs, especially power batteries.

Emerging two-dimensional (2D) MXene-based nanostructured materials: Synthesis strategies, properties, and applications as efficient pseudo-supercapacitors

Supercapacitors, which are essential for addressing modern energy challenges, possess outstanding energy storage capabilities without requiring manual maintenance. However, their low energy density and capacity limit their applicability for electrode materials. Recently, two-dimensional materials (2D), and particularly 2D transition metal carbonitrides (MXenes) have attracted considerable interest for developing energy storage devices because of their large specific surface area and fast ion-transport pathways. MXenes mainly comprise a transition metal (M) layer, carbon and/or nitrogen (X) layer, and active functional groups exterior to the layer. Metallic properties of the M layer offer excellent pseudocapacitance characteristics, while X layer is characterized by abundant active sites and conductivity similar to that of graphene. Compared with conventional materials, the existence of various functional groups on the surface of MXenes endows them with stronger hydrophilicity and higher wettability in aqueous electrolytes, which, combined with their diverse frame structures and functional group combinations, significantly augment their applicability for energy storage devices. Therefore, it is necessary to summarize and analyze the research results on MXenses. This review addresses the applications of MXenes in energy storage supercapacitors along with current challenges and solutions including intercalation, doping, surface modification methods, and heterogeneous structures. Finally, the prominent contemporary research trends are comparatively discussed to promote research and development in this field in the near future.

Swan feather-spired fluorine-free superhydrophobic self-cleaning cotton cloth with strong oil-water separation function

With the increasing demand of oil-water separation, superhydrophobic materials have garnered tremendous research attention due to their excellent oil-water separation efficiency. However, the biological toxicity and poor durability of fluorine-containing compounds in superhydrophobic materials severely restrict their application. In this work, inspired by the superhydrophobic/lipophilic swan feathers, we proposed a two-stage thiol-ene click reaction strategy to fabricate a fluorine-free superhydrophobic and super-lipophilic oil/water separation membrane (Cotton-S-PB-SiO2). Firstly, based on this thiol-ene click reaction, the rubber molecular chain 1,2-polybutadiene (1,2-PB) with low surface energy was coated with cotton fiber through chemical bonds. Subsequently, the coated cotton fiber was employed to establish chemical bonds with silica. The Cotton-S-PB-SiO2 possessed low surface energy and abundant micro-nano structures. Meanwhile, the Cotton-S-PB-SiO2 showed extremely high wettability selectivity to water and oil phases. The flux reached 44,554 L m−2 h−1, and the separation efficiency for immiscible oil/water mixtures was above 99.9 %. More remarkably, the Cotton-S-PB-SiO2 demonstrated excellent anti-fouling and operation stability even under some harsh environments such as strong acid, alkali, salt, etc. The prepared self-cleaning cotton cloth provides insights toward mild, low-cost and high-efficiency oil-water separation.

Different Roles of Surface Chemistry and Roughness of Laser-Induced Graphene: Implications for Tunable Wettability.

The control of surface wettability is a technological key aspect and usually poses considerable challenges connected to high cost, nanostructure, and durability, especially when aiming at surface patterning with high and extreme wettability contrast. This work shows a simple and scalable approach by using laser-induced graphene (LIG) and a locally inert atmosphere to continuously tune the wettability of a polyimide/LIG surface from hydrophilic to superhydrophobic (Φ ∼ 160°). This is related to the reduced amount of oxygen on the LIG surface, influenced by the local atmosphere. Furthermore, the influence of the roughness pattern of LIG on the wettability is investigated. Both approaches are combined, and the influence of surface chemistry and roughness is discussed. Measurements of the roll-off angle show that LIG scribed in an inert atmosphere with a low roughness has the highest droplet mobility with a roll-off angle of ΦRO = (1.7 ± 0.3)°. The superhydrophobic properties of the samples were maintained for over a year and showed no degradation after multiple uses. Applications of surfaces with extreme wettability contrast in millifluidics and fog basking are demonstrated. Overall, the proposed processing allows for the continuous tuning and patterning of the surface properties of LIG in a very accessible fashion useful for "lab-on-chip" applications.

Experimental study on exploration of optimum extinguishing agent for 243 Ah lithium iron phosphate battery fires

Nowadays, an effective and clean extinguishing agent or technology is highly desirable for lithium-ion battery (LIB) fires. Herein, the physicochemical properties and extinguishing effects of various extinguishing agents on 243 Ah lithium iron phosphate (LFP) battery fires are investigated systematically. The extinguishing mechanisms are deeply analyzed and the performance is comprehensively evaluated from the aspects of thermal runaway (TR) and toxicity suppression, cooling and extinguishing efficiency. Compared with HFC-227ea, C6F12O can absorb more heat through vaporization, thereby improving extinguishing and cooling efficiency. The lack of chemical inhibition effect and the tiny droplet size make water mist unable to suppress the high-temperature jet fire, but it has the lowest toxicity and highest cooling efficiency of 54.6%. F-500 and FireIce can improve the extinguishing performance of the water mist by encapsulating and taking hydrocarbon fuel away from the fire zone and inhibiting free radicals in the flame, respectively. 3% F-500 has the extinguishing efficiency of 78.4% and TR efficiency of 64.1%, while maintaining the cooling performance well. In the future, a novel type of fire-extinguishing agent with high heat capacity and latent heat, excellent extinguishing performance, high wettability, low toxicity and insulating properties is expected to be developed for LIB fires.

High potential for foliar water uptake in early stages of leaf development of three woody angiosperms.

Foliar water uptake (FWU) is a widespread mechanism that may help plants cope with drought stress in a wide range of ecosystems. FWU can be affected by various leaf traits, which change during leaf development. We exposed cut and dehydrated leaves to rainwater and measured FWU, changes in leaf water potential after 19 h of FWU (ΔΨ), minimum leaf conductance (gmin ), and leaf wettability (abaxial and adaxial) of leaves of Acer platanoides, Fagus sylvatica, and Sambucus nigra at three developmental stages: unfolding (2-5-day-old), young (1.5-week-old) and mature leaves (8-week-old). FWU and gmin were higher in younger leaves. ΔΨ corresponded to FWU and gmin in all cases but mature leaves of F. sylvatica, where ΔΨ was highest. Most leaves were highly wettable, and at least one leaf surface (adaxial or abaxial) showed a decrease in wettability from unfolding to mature leaves. Young leaves of all studied species showed FWU (unfolding leaves: 14.8 ± 1.1 μmol m-2 s-1 ), which may improve plant water status and thus counterbalance spring transpirational losses due to high gmin . The high wettability of young leaves probably supported FWU. We observed particularly high FWU and respective high ΔΨ in older leaves of F. sylvatica, possibly aided by trichomes.