Hydrophilic Groups Research Articles

Ultra-highly efficient adsorbent for CO2 capture from air by directional deprotonation regulation of MOFs-based amine grafting

In recent years, the solid amine of Metal-Organic Frameworks (MOFs) has shown promise as a direct air capture (DAC) adsorbent. However, the efficiency of amine groups under ultra-low CO2 concentrations requires improvement. In this study, we propose a novel method to regulate proton migration through solvent effects during amine grafting, to enhance the synthesis of MOFs as solid amine adsorbents and improve amine group utilization. This approach yielded outstanding results with a MIL-100(Cr)-based DAC adsorbent, demonstrating a CO2 adsorption capacity of 2.15 mmol/g and an ultra-high amine group utilization of 89.6 % at ambient conditions. By directional deprotonation regulation, the CO2 adsorption performance of the UiO-66(Zr)-based adsorbent significantly increased from 0.06 mmol/g of using H2O as solvent to 1.71 mmol/g of using NMP, with a 27.5-fold increase. Specifically, organic polar aprotic solvents enhanced the binding energy and reduced the energy barrier for deprotonation during the grafting process, thereby improving CO2 adsorption performance and amine group utilization, which shed a new light on the development of MOFs based CO2 adsorbent. Furthermore, due to the coordination of secondary amine groups with metal sites leads to the decrease of hydrophilic functional groups in the CO2 adsorption products, the hydrophobicity of products was reduced significantly resulting in an increase in the ΔS of the hydrated ion pairs after the adsorption, which reduced the heat of CO2 adsorption about 15 % than that reported in the literature. Based on changes in humidity conditions, the regeneration energy consumption of the MF-Cr-AEEA is less than 2.5 GJ/t CO2 under a relatively lower humidity, demonstrating outstanding industrial applications potential of the adsorbent.

HALS-770 interlayer simultaneously block internal and external degradation paths of perovskite for stability and high efficiency perovskite solar cells

The stability of perovskite solar cells (PSCs) is a major problem limiting their application. Here, we proposed a feasible solution using bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (HALS-770) as top protection layer of perovskite. HALS-770 interlayer can not only improve the antioxidant ability of perovskite by removing superoxide (O2·-) with help of hindered amine groups, but also suppress the internal and external degradation path of perovskite due to the co-existence of hydrophilic and hydrophobic groups. Moreover, it can block volatilization of organic cation and the migration of Ag+ and I-, thus improve thermal stability of perovskite and alleviate destruction of Ag electrode. In addition, the heterocycles N atom and carbonyl group in HALS-770 interact with the under-coordinated Pb2+, reducing the interface defects. As a result, the unencapsulated device maintains excellent stability over 95 % of its initial efficiency after 30 days in ambient condition with about 25–50 % humidity, and possesses remarkable continuous operation stability with projected T80 > 1400 h at maximum power point tracking in glove box, much higher than those of the pristine device. Meanwhile, HALS-770 enable the PCE of 21.88 % for PSC (0.06 cm2), which is among the highest efficiencies for MAPbI3 based PSCs with p-i-n structure, and the PCE of 19.07 % for PSM (4 cm2). And it is also suitable for FAMA-based devices with n-i-p structure, enabling an efficiency of 23.03 % (0.06 cm2) and excellent stability.

Carbon nanotube-confined NiCoLDH heterostructures for ultrahigh stable supercapacitors

The structural instability of metal oxides retards realizing high-performance and long lifespan supercapacitors. We prepare an electrochemical active heterostructure of NiCo layered double hydroxide (LDH) confined by carboxyl carbon nanotube (CNTCOOH). Through the electrostatic interactions between carboxyl groups (COO−) of CNTCOOH and metal cations of LDH under a simple hydrothermal treatment, the CNTCOOH confined NiCoLDH (CNTCOOH-c-NiCoLDH) can be easily fabricated. The CNTCOOH-c-NiCoLDH demonstrates the specific morphology of rope-fastened plates and shows ultrahigh cycled stability. In addition, the hydrophilic carboxyl groups on CNTCOOH also regulates the interfacial electronic coupling and electrolyte soaking, resulting in high rate capability. The charge-storage capacitance of CNTCOOH-c-NiCoLDH heterostructures reaches 2120.8 F/g at 1 A/g. The devices of CNTCOOH-c-NiCoLDH//AC show both high energy density (171.0 Wh/kg) and high power density (950.0 W/kg), and have ultrahigh capacity retention rate of 93.64 % after 50,000 charge and discharge cycles at a high current density of 5 A/g. This work supports an effective confinement idea and a facile method that can be applied on a large scale for the design and fabrication of super high stable metal oxide-based supercapacitors.

Composite porous 3D foam for solar-driven atmospheric water harvesting in low humidity natural environment

Solar-driven atmospheric water harvesting (SAWH) has been recognized as a promising strategy to alleviate the freshwater crisis. Herein, we developed an efficient porous polymeric foam, LiCl@CCP-PPy, which has low preparation cost, strong adaptability and portability, and is very suitable for use as a wicking material in SAWH systems. LiCl@CCP-PPy contains abundant –NH2 and –OH groups. These hydrophilic groups and excellent pore structure (porosity is 80.22 %) make it have a good moisture absorption effect even in low humidity environment. The moisture absorption capacity can reach 2.86 g/g at 35 % RH and 25 °C, and 4.48 g/g at 25 °C and 90 % RH. The saturated water absorption effect was 27.48 g/g. LiCl@CCP-PPy can be scaled up for production. In addition, LiCl@CCP-PPy has a high light absorption rate of more than 90 %, and the strong photothermal conversion ability of Polypyrene (PPy) enables the material to warm up rapidly under natural light, thereby accelerating the desorption process (96 % desorption rate at 1 kW/m2 for 3 h). Based on the above properties, LiCl@CCP-PPy was applied to the Tengger desert in northwest China. The final water production efficiency was 0.64 L/m2/d, and the collected water quality met the international drinking water standard.

Synergetic conditioning via oxalic acid enhanced Fe2+/CaO2 and skeleton construct to achieve deep dewatering of sewage sludge

Extracellular polymeric substance (EPS) with highly hydrophilic groups and sludge with high compressibility are determined sludge dewaterability. Herein, Fe2+ catalyzed calcium peroxide (CaO2) assisted by oxalic acid (OA) Fenton-like process combined with coal slime was applied to improve sludge dewaterability. Results demonstrated that the sludge treated by 0.45/1/1.1-OA/Fe2+/CaO2 mM/g DS, the water content (WC), specific resistance to filtration and capillary suction time dropped to 53.01%, 24.3 s and 1.2 × 1012 m/kg, respectively. Under coal slime ratio as 0.6, WC and compressibility were further reduced to 42.72% and 0.66, respectively. The hydroxyl radicals generated by OA/Fe2+/CaO2 under near-neutral pH layer by layer collapsed EPS, resulting in the degradation and migration of inner releasing components and the exposure of inner sludge flocs skeleton. The hydrophilic tryptophan-like protein of TB-EPS were degraded into aromatic protein of S-EPS and exposed inner hydrophobic sites. The protein secondary structures were transformed by destroying hydrophilic functional groups, which were attributed to the reducing α-helix ratio and reconstructing β-sheet. Moreover, coal slime as the skeleton builder lowered compressibility and formed more macropores to increase the filterability of pre-oxidized sludge for the higher intensity of rigid substances. This study deepened the understanding of OA enhanced Fenton-like system effects on sludge dewaterability and proposed a cost-effective and synergistic waste treatment strategy in sludge dewatering.

Superabsorbent quaternary ammonium guar gum hydrogel with controlled release of humic acid for soil improvement and plant growth

Growing plants in karst areas tends to be difficult due to the easy loss of water and soil. To enhance soil agglomeration, water retention, and soil fertility, this study developed a physically and chemically crosslinked hydrogel prepared from quaternary ammonium guar gum and humic acid. The results showed that non-covalent dynamic bonds between the two components delayed humic acid release into the soil, with a release rate of only 35 % after 240 h. The presence of four hydrophilic groups (quaternary ammonium, hydroxyl, carboxyl, and carbonyl) in the hydrogel more than doubled the soil's water retention capacity. The interaction between hydrogel and soil minerals (especially carbonate and silica) promoted hydrogel-soil and soil‑carbonate adhesion, and the adhesion strength between soil particles was enhanced by 650 %. Moreover, compared with direct fertilization, this degradable hydrogel not only increased the germination rate (100 %) and growth status of mung beans but also reduced the negative effects of excessive fertilization on plant roots. The study provides an eco-friendly, low-cost, and intelligent system for soil improvement in karst areas. It further proves the considerable application potential of hydrogels in agriculture.

A dual-crosslinking strategy for waterborne polyurethane coatings to achieve outstanding anti-smudge and anti-corrosion properties

The inferior anti-smudge properties and compromised anti-corrosion performance of waterborne polyurethanes (WPUs) stem from the presence of abundant hydrophilic groups in their polymer networks. Despite various hydrophobic segments have been introduced in WPU skeleton to lower the impacts of hydrophilic groups, the limited migration capability of hydrophobic segments in waterborne matrix often result in unsatisfactory performance. Herein, we fabricate a multifunctional PDMS-modulated WPU coating employing sorbitan monooleate (SP), a renewable bio-derived polyol, as an internal crosslink agent, and hexamethoxymethylmelamine (HMMM) as a post-crosslink agent to fully eliminate the polar hydrophilic groups in the molecular linkages and further enhance the crosslink density of the coating. It is found that the coating exhibits exceptional anti-graffiti and self-cleaning effects when subjected to tests involving oil-based and water-based pens and inks, as well as common household liquids like milk, coffee, cooking oil, ethanol, n-hexadecane, etc. Such anti-smudge coating could readily remove carbon powder-like dust with water, ensuring a clean surface, and also possess a certain level of resistance to fingerprint smudges. Apart from excellent mechanical robustness and impressed durability after 500 cycles of writing erase tests, the coating also remains intact and has anti-smudge properties when folded or bent. For chemical resistance, the coating can resist at least 18 h of acid, alkali, and salt intrusion without being damaged. Moreover, the sufficient crosslink density imparts the coating with good thermal stability and outstanding anti-corrosion performance in extremely corrosive environments. This research presents a facile and effective approach for developing stain and corrosion-resistant PDMS-modulated waterborne polyurethane materials with high protective reliability and long lifespan through the dual-crosslinking strategy.

Hydrophilic Modification of Polytetrafluoroethylene (PTFE) Capillary Membranes with Chemical Resistance by Constructing Three-Dimensional Hydrophilic Networks.

Polytetrafluoroethylene (PTFE) capillary membranes, known for the great chemical resistance and thermal stability, are commonly used in membrane separation technologies. However, the strong hydrophobic property of PTFE limits its application in water filtration. This study introduces a method whereby acrylamide (AM), N, N-methylene bisacrylamide (MBA), and vinyltriethoxysilane (VTES) undergo free radical copolymerization, followed by the hydrolysis-condensation of silane bonds, resulting in the formation of hydrophilic three-dimensional networks physically intertwined with the PTFE capillary membranes. The modified PTFE capillary membranes prepared through this method exhibit excellent hydrophilic properties, whose water contact angles are decreased by 24.3-61.2%, and increasing pure water flux from 0 to 1732.7-2666.0 L/m2·h. The enhancement in hydrophilicity of the modified PTFE capillary membranes is attributed to the introduction of hydrophilic groups such as amide bonds and siloxane bonds, along with an increase in surface roughness. Moreover, the modified PTFE capillary membranes exhibit chemical resistance, maintaining the hydrophilicity even after immersion in strong acidic (3 wt% HCl), alkaline (3 wt% NaOH), and oxidative (3 wt% NaClO) solutions for 2 weeks. In conclusion, this promising method yields modified PTFE capillary membranes with great hydrophilicity and chemical resistance, presenting substantial potential for applications in the field of water filtration.

Influence of Oxygen/Argon/Nitrogen multi-component plasma modification on interlayer toughening of UHMWPE fiber reinforced composites

The study reveals the influence of glow discharged three gas sources of Oxygen/Argon/Nitrogen plasma modification on interlayer toughening of ultra-high molecular weight polyethylene (UHMWPE) fiber reinforced composite. The failure modes under bending, tensile and interlayer fracture toughness testing were analyzed through acoustic emission (AE) technology. The results showed that Oxygen/Argon/Nitrogen multi-component plasma modified fiber introduced more hydrophilic groups such as hydrogen and hydroxyl groups, and significantly enhanced the binding of fiber and matrix. The GⅠC (Mode-I interlaminar fracture toughness) of multi-component plasma modified composites exhibited increased by 61.67 %, 40.88 % and 18.01 % compared to untreated, Oxygen and Oxygen/Argon plasma, respectively, while GⅡC (Mode-II interlaminar fracture toughness) increased by 38.57 %, 25.57 % and 23.09 %. AE cluster analysis exhibited that multi-component plasma modified composites formed an energy dissipation mechanism dominated by fiber breakage. Additionally, the oxygen, argon, and nitrogen plasma modification have a synergistic effect on interlayer toughening.

Soot aerosols from commercial aviation engines are poor ice-nucleating particles at cirrus cloud temperatures

Abstract. Ice-nucleating particles catalyze ice formation in clouds, affecting climate through radiative forcing from aerosol–cloud interactions. Aviation directly emits particles into the upper troposphere where ice formation conditions are favorable. Previous studies have used proxies of aviation soot to estimate their ice nucleation activity; however, investigations with commercial aircraft soot from modern in-use aircraft engines have not been quantified. In this work, we sample aviation soot particles at ground level from different commercial aircraft engines to test their ice nucleation ability at temperatures ≤228 K as a function of engine thrust and soot particle size. Additionally, soot particles were catalytically stripped to reveal the impact of mixing state on their ice nucleation ability. Particle physical and chemical properties were further characterized and related to the ice nucleation properties. The results show that aviation soot nucleates ice at or above relative humidity conditions required for homogeneous freezing of solution droplets (RHhom). We attribute this to a mesopore paucity inhibiting pore condensation and the sulfur content which suppresses freezing. Only large soot aggregates (400 nm) emitted under 30 %–100 % thrust conditions for a subset of engines (2 out of 10) nucleate ice via pore condensation and freezing. For those specific engines, the presence of hydrophilic chemical groups facilitates the nucleation. Aviation soot emitted at thrust ≥ 100 % (sea level thrust) nucleates ice at or above RHhom. Overall, our results suggest that aviation soot will not contribute to natural cirrus formation and can be used in models to update impacts of soot–cirrus clouds.

Enhancing performances of inverted perovskite solar cells by modifying the buried interface with sodium copper chlorophyllin

Defects at the buried interface and poor contact between the hole transport layer (HTL) poly-triarylamines (PTAA) and the perovskite layer are key issues affecting the efficiency and long-term stability of inverted perovskite solar cells (PSCs). In this study, we introduce sodium copper chlorophyllin (SCC, a chlorophyll derivative) as a modification agent at the HTL/perovskite interface to address these issues. Attributed to hydrophilic carboxylate groups of SCC, the wettability of the PTAA film is enhanced, facilitating the formation of the high-quality perovskite film. Meanwhile, SCC can interact with uncoordinated Pb2+ to passivate defects of the perovskite film at the buried interface. As a result, the power conversion efficiency (PCE) of inverted PSCs with the SCC modification reaches to 22.37% (from 20.58%) based on MAPbI3, and to 24.06% (from 21.54%) based on FAPbI3, respectively. Moreover, the devices show excellent stability in air and under light irradiation. This work indicates that the natural chlorophyll derivative is a promising candidate for improving the buried interface of high-performance inverted PSCs.

Inkjet printing of triethylene glycol monomethyl ether (TEGMME)-based ink droplet on oxygen plasma treated PDMS substrate for flexible circuit

Circuits fabricated by inkjet printing on polydimethylsiloxane (PDMS) substrate is a promising direction of flexible electronics. Oxygen plasma treatment is a commonly used method to modify PDMS from hydrophobic to hydrophilic, which is prerequisite before inkjet printing. In this study, inkjet printing of triethylene glycol monomethyl ether (TEGMME)-based silver dispersion nanoparticle droplets on oxygen plasma treated PDMS was investigated by molecular dynamics simulations and experiments. It is revealed that the improved hydrophilicity of PDMS surface is contributed to the replacement of hydrophilic groups (-OH and -C=O) from hydrophobic groups (-CH3) on the PDMS molecular chains. Considering the existence of hydroxyl groups in TEGMME molecules, more hydrogen bonds are formed at the interface between the treated PDMS and TEGMME-based droplets during printing process. These significantly optimize the merging of droplets and the distribution of silver nanoparticles. Moreover, too short plasma treatment will lead to poor circuit morphology caused by weak hydrophilicity, while too long treatment will lead to defects caused by coffee ring effect. The suggested process parameter is treating PDMS for 30 s at a radio-frequency power of 45 W. The morphology of printed circuit is greatly improved and the resistivity decreased to 2.5 Ω/mm. A PDMS-based pressure sensor is designed and fabricated by the proposed inkjet printing process, which shows a sensitivity of 1.8 Ω/kPa and R2 of 0.98.

Thiol‐Ene Photo Crosslinked PUA‐PUMA‐Based Flexible Gel Polymer Electrolyte for Lithium‐Ion Batteries

AbstractCrosslinked polymer films, formed via sol–gel and UV photocrosslinking, serve as gel polymer electrolytes (GPEs) in lithium‐ion batteries. Combining polyurethane acrylate (PUA), polyurethane methacrylate (PUMA), pentaerythritol tetrakis (3‐mercaptopropionate) (PETMP), and 3‐mercaptopropyl trimetoxysilane (MPTMS) yields flexible membranes, enhancing stability and liquid electrolyte compatibility. The resulting GPE displays higher ionic conductivity (1.46 × 10−3 S cm−1) than Celgrad2500, with PUA‐PUMA's hydrophilicity and PETMP's SH groups preventing leakage. GPPF1, the developed GPE, offers improved ionic conductivity, a stable electrochemical window up to 3.8 V, and heightened safety for versatile energy storage systems.

Influence of surfactant adsorption on coal oxidation and wettability: Experimental discussion and model development

To further investigate the physicochemical properties and wettability changes of surfactant-modified coal after oxidation, the contact angle, industrial composition, and functional groups of the surfactant-modified coal were measured. The experimental data were analyzed using a ridge regression prediction model to explore the relationship between the physicochemical properties and the wettability. The results indicate that the oxidated-modified coal has a worse wettability at room temperature. The adsorption of SL and CDEA surfactants effectively impedes the increase in the contact angle of the oxidized coal. The hydrophilic functional group (2#CO, C–O–C, RHCCH2) in coal demonstrates higher sensitivity to surfactants, while the hydrophobic functional group (2# Free OH, 1#CC) exhibits greater reactivity. There is a strong correlation between the industrial composition, structural parameters, and the contact angle. The quantitative influence of the parameters on the contact angle is as follows: FCad > Vad > P1 ≥ P4 ≥ Mad ≥ P3 ≥ P2. A coal wetting model is established that considers the combined action of surfactants and coal quality. These findings suggest that wettability is determined by multiple parameters, providing a basis for discovering new reagents that significantly enhance coal wettability and reduce coal oxidation activity.

Enhancing Efficiency and Stability in Carbon-Based Perovskite Solar Cells by Double Passivation with Ultralow-Cost Coal-Derived Graphene and Its Derivatives.

Coal-derived carbon nanomaterials possess numerous superior features compared to other classic carbon, such as readily accessible surfaces, tunable pore structure, and facile and precise surface functionalization. Therefore, the controllable preparation of coal-derived carbon nanomaterials is anticipated to be of great significance for the performance improvement and commercialization process of carbon-based perovskite solar cells (C-PSCs). In this study, we successfully synthesized highly stable and commercially valuable graphene oxide (GO) and reduced graphene oxide (rGO) utilizing coal. Compared to traditional methods and commercial graphene, the chemical oxidation and pyrolysis process used in this study is mild and simple, offering the advantages of controlled composition and the absence of other impurities. GO or rGO was incorporated into the top of the SnO2 electron transport layer (ETL) of C-PSCs. Under optimized conditions and ultraviolet-ozone (UVO) irradiation, the ultimate power conversion efficiency (PCE) increased from the unmodified 12.4 to 14.04% (based on rGO) and 15.18% (based on GO), representing improvements of 22 and 31%, respectively. The improved photovoltaic performance is mainly owing to enhanced charge transport capabilities, denser interfacial contacts, improved carrier separation properties, increased conductivity, and abundance of hydrophilic functional groups in GO, which can form more stable hydrogen bonds with SnO2. After being stored at room temperature and ambient humidity for 30 days, the modified, unpacked devices retained 87% of the highest power conversion efficiency (PCE). This study introduces a practical and manageable method to enhance the performance of C-PSCs by using functional carbon nanomaterials derived from coal.

Effect of cationic Gemini surfactants ethonium and decamethoxin on the spectral properties, solubility and tautomerism of the curcumin

AbstractThe properties of natural polyphenol curcumin in water solutions of cationic Gemini surfactants decamethoxin and ethonium, which have similar positively charged nitrogen hydrophilic head groups but different spacer sizes and lengths of hydrophobic tails have been investigated in a wide range of concentrations by using UV–Vis spectroscopy and quantum‐chemical calculations. It was found that curcumin dissolves in the organized micellar media of these surfactants in the enol tautomeric form and its solubility increases 400 times compared to water. The binding constants of curcumin with decamethoxin and ethonium were determined by the solubility method. Significant differences in the influence of premicellar concentrations of cationic Gemini surfactants on the solubility and tautomeric transformations of curcumin were revealed. In contrast to decamethoxin, ethonium at a concentration below the CMC promotes a significant increase in the solubility of curcumin and a shift in the tautomeric equilibrium towards the formation of its keto form.

Nanoscale Stabilization Mechanism of Sodium Sulfate Decahydrate at Polyelectrolyte Interfaces.

Sodium sulfate decahydrate (SSD) is a low-cost phase-change material (PCM) for thermal energy storage applications that offers substantial melting enthalpy and a suitable temperature range for near-ambient applications. However, SSD's consistent phase separation with decreased melting enthalpy over repeated thermal cycles limits its application as a PCM. Sulfonated polyelectrolytes, such as dextran sulfate sodium (DSS), have shown great effectiveness in preventing phase separation in SSD. However, there is limited understanding of the stabilization mechanism of SSD by DSS at the atomic length and time scales. In this work, we investigate SSD stabilization via DSS using neutron scattering and molecular dynamics (MD) simulations. Neutron scattering and pair distribution function analysis revealed the structural evolution of the PCM samples below and above the phase change temperatures. MD simulations revealed that water from the hydrate structure migrates from the hydrate crystal to the SSD-DSS interfacial region upon melting. The water is stabilized at this interface by aggregation around the hydrophilic sulfonic acid groups attached to the backbone of the polyelectrolyte. This architecture retains water near the dehydrated sodium sulfate, preventing phase separation and, consequently, stabilizing SSD rehydration. This work provides atomistic insight into selecting and designing stable and high-performance PCMs for heating and cooling applications in building technologies.

Development of D-π-A organic dyes for discriminating HSA from BSA and study on dye-HSA interaction

HSA (human serum albumin), a most abundant protein in blood serum, plays a key role in maintaining human health. Abnormal HSA level is correlated with many diseases, and thus has been used as an essential biomarker for therapeutic monitoring and biomedical diagnosis. Development of small-molecule fluorescent probes allowing the selective and sensitive recognition of HSA in in vitro and in vivo is of fundamental importance in basic biological research as well as medical diagnosis. Herein, we reported a series of new synthesized fluorescent dyes containing D-π-A constitution, which exhibited different optical properties in solution and solid state. Among them, dye M−H−SO3 with a hydrophilic sulfonate group at electron-acceptor part displayed selectivity for discrimination of HSA from BSA and other enzymes. Upon binding of dye M−H−SO3 with HSA, a significant fluorescence enhancement with a turn-on ratio about 96-fold was triggered. The detection limit was estimated to be ∼ 40 nM. Studies on the interaction mechanism revealed that dye M−H−SO3 could bind to site III of HSA with a 1:1 binding stoichiometry. Furthermore, dye M−H−SO3 has been applied to determine HSA in real urine samples with good recoveries, which provided a useful method for HSA analysis in biological fluids.

Nanoscale hydrate adhesion on organic surfaces

The future of addressing persistent gas hydrate blockages in oil and gas pipelines lies in the realm of surface material design, aimed at reducing environmental harm and energy inefficiencies associated with traditional chemical additives or heat-based approaches. A comprehensive understanding of hydrate-surface interactions is crucial for effective material-based solutions. Our study examined gas hydrate adhesion on diverse organic monolayer surfaces, utilizing Molecular Dynamics (MD) simulations to explore the impact of surface flexibility, gas concentration, and crack locations on hydrate adhesion strength. Results highlight the dependence of adhesion strength on surface functional groups. Hydrophobic interfaces are susceptible to weakening through a “gas coating”, while hydrophilic groups, like hydroxyl, strengthen adhesion through hydrogen bonding, altering the fracture behavior from adhesive failure to cohesive failure. Unexpectedly, the flexibility of monolayers has minimal influence, especially on hydrophobic surfaces. Tensile testing identified six distinct fracture interfaces, with the ice-hydrate interface displaying the highest adhesion strength, highlighting the detrimental impact of hydrogen bonding on interface weakening. These findings significantly deepen the understanding of soft surface properties influencing gas hydrate adhesion, offering a valuable guide for designing and fabricating highly efficient flexible anti-hydrate surfaces.

Nickel aerogel @ ultra-thin NiCo-LDH nanosheets integrated freestanding film as a collaborative adsorption and accelerated conversion cathode to improve the rate performance of lithium sulfur batteries

It is a great challenge to develop freestanding ultralight cathodes for lithium–sulfur battery exhibiting good electrochemical performances. Herein, ultrathin porous nickel–cobalt layered double hydroxide (NiCo-LDH) nanosheets were grown on the surface of ultra-light nickel microwire aerogels (NMWAs), and there is capillary action in the gaps formed by the ordered arrangement due to the presence of magnetic filed in the preparation process, which has the advantages of synergistic adsorption and accelerated conversion kinetics of lithium polysulfide. Because of the abundant hydrophilic hydroxyl groups on the surface of NiCo-LDH and the capillary action of NMWAs, the integrated freestanding film cathode sulfur host (NMWAs@NiCo-LDH/S) provides excellent rate performance as well as cycling stability. The film cathode has an ultra-high initial specific capacity of 1238.4 mAh g−1 at 0.1C and an excellent reversible capacity of 805.8 mAh/g at 5.0C. Even after 700 cycles at a high current density of 5.0C, it still provides a reversible capacity of 647.1 mAh g−1 with a capacity decay rate of only 0.018 % per cycle. This work provides a simple and new way for the design of high rate lithium–sulfur battery film cathodes with good cycle stability.