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The present studies shed light on the continuum breakdown of water confined in nanotubes of different materials and diameters. The structure and hydrodynamics of water confined in nanotubes of carbon (CNT), boron nitride (BNNT), silicon carbide (SiC), and silicon nitride (SiNT) of different chirality indices were analyzed to examine the potential nanomembrane material for water purification. According to our findings of the contact angle with water, BNNTs are more hydrophobic than CNTs, and silica nanotubes are hydrophilic. The higher permeability of water was observed through CNTs and BNNTs in comparison to silica nanotubes. Nearly flat velocity profiles indicated continuum breakdown at the nanoscale. Also, the trend for viscosity and diffusion coefficient did not follow the Stokes–Einstein relation, indicating continuum breakdown. The results demonstrated the connectivity of microscopic diffusion with the macroscopic permeation flux, which might be important information for the theoretical investigation of the suitable operational regime in reverse osmosis. Essentially, the continuum breakdown due to freezing of water was seen to be diminished with an increase in temperature. The results showed characteristic changes in the density profile, diffusion coefficient, velocity autocorrelation functions, density of state functions, and thermodynamic entropic components (evaluated using the two-phase thermodynamic method) of permeating water molecules. Importantly, our results reflect that the continuum breakdown observed for water confined in smaller nanotubes is true only at temperatures below 400 K due to the ice-like dense structure of water molecules. Once the entering water molecules can gain energy to compensate for the loss of H bonds, the conventional fluid dynamics relations can be well applied to estimate the hydrodynamics of confined water. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2), as a versatile and environmentally friendly oxidant, has drawn increasing attention in energy and environmental applications. Aiming at boosting the in situ electrocatalytic H2O2 production and activation toward water purification, we developed a two-dimensional (2D) CuO nanosheet-modified activated carbon fiber (CuO NSs/ACF) bifunctional free-standing hybrid composite electrode. The introduction of 2D CuO NSs well modulated the electronic structure and surface wettability of hybrid electrodes, promoting the two-electron oxygen reduction reaction (ORR) for H2O2 generation and the following CuO-catalyzed Fenton efficiency. Taking bisphenol A (BPA) as the target pollutant, the BPA degradation and TOC removal could reach 99.45 and 74.04%, respectively, after 30 min electrolysis. We identified the reactive oxygen species (•OH and •O2–) produced in the CuO NSs/ACF system and further discussed the tuning mechanisms. This work provided a promising 2D material modification strategy for boosting in situ electrochemical H2O2 production and electro-Fenton activity and facilitating its application for water purification. [ABSTRACT FROM AUTHOR]

Thin hydrophobic polyoligosiloxysilicone (POSiSil) films were synthesized on silicon wafer substrates by spin coating reactive nanometer-sized spherosilicate solutions. Surface roughness was spontaneously induced due to the generation of HCl gas bubbles during the coating procedure, involving the cross-linking and solidification of spherosilicates. Variations in the coating solution and/or relative humidity during the curing phase allowed for a degree of precision in controlling this roughness, thereby impacting parameters such as the porosity and the static contact angle of water on the surface. The introduction of Pluronic 123 into the coating solution, followed by a calcination step after curing, was employed to further augment the surface roughness and porosity. Coatings characterized by uniform foam-like morphologies were synthesized, exhibiting static water contact angles as elevated as 135°. These hydrophobic POSiSil thin films with thicknesses in the nanometer scale have minimal interaction with water, as evidenced by wetting experiments conducted during the ellipsometry. The films also demonstrate the high chemical and thermal stability with no change in the morphology or static contact angle with water. The presence of significant surface area, resulting from the foam-like matrix, coupled with its innate hydrophobic properties and a relatively simple and easily attainable synthesis process, bestows upon the POSiSil coatings considerable potential across a broad spectrum of applications. One noteworthy application includes their use in the detection of volatile organic compounds. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Crystal fouling, which refers to the accumulation of precipitates on surfaces and the associated damage, is a common problem in many industrial processes. In deepwater oil and gas transportation, hydrate blockage poses as a considerable barrier. Consequently, modifying hydrophobicity of surfaces has become an increasingly focused strategy to mitigate hydrate. However, the design of surfaces that effectively control the hydrate remains challenging. Herein, we report a superior smooth anti-hydrate material based on silanized modification. The low-adhesion silanized silicon wafer (SSW) realizes a win-win strategy of hard formation and easy removal. Through a comprehensive study combining experimental validation with theoretical analysis, the unique characteristics of SSW in the field of anti-hydrate surfaces were deeply discussed. Various hydrate crystals exhibited a completely different hydrate growth mode at the SSW surface, in which hydrate crystals spontaneously elevated and lifted themselves off from the surface. The presence of the fluorine element on the SSW surface allowed self-lifting growth of hydrate crystals after they covered the water droplet. And the loose and porous crystal structure in this self-lifting growth could reduce the contact area between the hydrate crystals and the substrate, allowing the crystals with minimal adhesion force and removal disturbance. Furthermore, the gas enrichment on the SSW surface also reduced the contact with the substrate, thereby decreasing the adhesion and allowing self-cleaning behavior. These results indicate that the silanized surface is a promising candidate for developing anti-hydrate materials for hydrocarbon production and transportation industry.

Understanding rock wettability is crucial across various fields including hydrology, subsurface fluid storage and extraction, and environmental sciences. In natural subsurface formations like carbonate and shale, mixed wettability is frequently observed, characterized by heterogeneous regions at the pore scale that exhibit both hydrophilic (water-wet) and hydrophobic (oil-wet) characteristics. Despite its common occurrence, the impact of mixed wettability on immiscible fluid displacement at the pore scale remains poorly understood, creating a gap in effective modeling and prediction of fluid behavior in porous media. The primary objective of this study was to investigate how mixed wettability affects pore-scale fluid displacement dynamics, utilizing microfluidic devices designed to replicate rock-like structures with varied wettability properties. Current techniques for achieving mixed wettability within microfluidic devices often struggle with spatial control and resolution, limiting their accuracy. To address this limitation, a novel approach was employed that combined photolithography and molecular vapor deposition of perfluorodecyltrichlorosilane to precisely and selectively modify wettability within specific pore regions, achieving a mixed wettability distribution correlated with pore size for the first time. The experimental setup included five identical micromodels representing distinct wetting conditions, which were initially saturated with air and subsequently flooded by water. By systematically varying the ratio of hydrophilic to hydrophobic areas, we covered a range from fully hydrophilic to fully hydrophobic and intermediate mixed wettability configurations. Comparative displacement experiments revealed that pore-level mixed wettability has a pronounced effect on fluid displacement behavior, influencing the injection time, spatial invasion patterns, and dynamic pressure profiles. Results indicated that both the injection time and dynamic pressure decreased with an increase in the hydrophilic area fraction. Each wettability configuration displayed unique sequences of pore-filling events, emphasizing the critical role of the wettability distribution in influencing displacement dynamics. While mixed wettability exhibited a clear monotonic effect on invasion time and dynamic pressure, saturation behavior was notably nonmonotonic. Interestingly, mixed wettability scenarios with relatively medium to high hydrophilic fractions demonstrated enhanced overall sweep efficiency compared to the hydrophobic case and reduced the bypassed gas phase relative to the hydrophilic case. However, inefficiently distributed mixed wet zones were found to reduce the sweep efficiency. These findings highlight the critical influence of mixed wettability in fluid displacement processes, with significant implications for applications in oil recovery, CO 2 sequestration, and other subsurface energy technologies.

The biocompatibility and adaptability of hydrogels make them ideal candidates for use as artificial tendons and muscles in clinical applications, where both muscle-like strength and low hysteresis are essential. However, achieving a balance between a high strength and low hysteresis in hydrogels remains a significant challenge. Herein, we demonstrated a self-assembly process of heterogeneous hydrogels to meet the dilemma. And the hydrogels are composed of both hydrophilic and hydrophobic polymers. The hydrophilic network absorbs water, causing phase separation into a water-rich phase and a water-poor phase, while hydrophobic polymers and entanglement of the network arrest phase separation. Our results demonstrated that these hydrogels achieve remarkable mechanical properties, with a strength of 848.8 kPa, a low energy loss of 19.6 kJ/m 3 , and minimal hysteresis (0.046) during loading-unloading cycles. The reinforcing mechanisms underlying these properties are attributed to crystallization, molecular entanglement, and chain rearrangement induced by stretching. Furthermore, the combination of hydrophilic and hydrophobic networks is exceedingly rare in reported hydrogels.

Microwave-stimulated smart self-healable polymeric coatings with significant protective technology against corrosion have been developed in this work. Herein, a generous approach is strategized to generate linseed oil-derived epoxy composites embedded with reduced graphene oxide (rGO) as a nanofiller in the shielding network. The composite showed excellent self-healing and shape memory properties when irradiated with microwaves due to the dynamic reversible nature of the disulfide covalent bond exchange mechanism. The network also has improved thermomechanical properties and thermal stability, with a storage modulus of 20.8 GPa and a low activation energy of 79 kJ/mol, indicating a fast disulfide dynamic exchange reaction. The amine functionality in the composite contributes to excellent corrosion protection, with 99.9% protection efficiency, as validated via a Tafel plot. The composite also showed excellent hydrophobicity, with a 131° contact angle. This study provides insights into the engineering and application of smart materials as anticorrosive coatings.

Problems resulting from the emission of crude oil, toxic organic solvents, and petroleum products, as well as massive heat dissipation from industrial pipes, have threatened ecosystems, human health, and industrial production. Eco-friendly and biodegradable natural materials are considered as the most promising absorbents or thermal insulation materials for oil–water separation and thermal insulation. In this work, agarose nanowire aerogels (ANAs) prepared from agarose (AG) solution were synthesized without any chemical reaction or chemical crosslinking agents to form AG hydrogels followed by supercritical CO2 (SC-CO2) drying. Then, hydrophobic agarose nanowire aerogels (HANAs) were obtained through a simple chemical vapor deposition (CVD) approach using methyltrimethoxysilane and methyltrichlorosilane. The gel skeleton of the HANAs after CVD was isometrically covered by a rigid silica coating with methyl on the ANA surface to improve flexibility, resulting in not only excellent self-cleaning and hydrophobicity with a water contact angle of 142° but also outstanding elasticity. Furthermore, the as-synthesized HANAs exhibited low density (≤0.09 g/cm3), a large specific surface area (≥210.5 m2/g), and high porosity (94.9–98.7%). Hence, the HANAs displayed high absorption capacities (approximately 48.2 g/g of chloroform absorption capacity) and selectivity of oils and organic solvents. In addition, they also exhibited excellent thermal insulation performance under both hot and cold conditions. The designed HANAs are expected to provide a highly efficient method for oil–water separation and thermal insulation. [ABSTRACT FROM AUTHOR]

Dew harvesting, minimally influenced by climate and geographical locations, is an ideal method for addressing water shortage problems. Superhydrophilic surfaces, characterized by their highest affinity for water, are particularly attractive for this purpose as they can attract more water molecules via condensation. However, a significant challenge arises from the high surface capillary force that impedes water from sliding down and being effectively collected. The resulting water film on the superhydrophilic surface tends to stay around the edge of the water collection surface, leading to evaporation loss and reduced collection efficacy. To overcome this problem, triangular patterns with low surface adhesion to water were introduced at the edge of superhydrophilic surfaces. This modification, achieved through a wet chemical method and masked oxygen plasma treatment, has significantly improved the efficiency of water collection. Results indicate that the hybrid surface reduced the time for the first water droplet to slide down by half and increased water collection efficiency by 78% compared to uniform superhydrophilic surfaces and by 536% compared to uniform superhydrophobic surfaces under a relative humidity of 55% with a temperature difference of 15 °C. The underlying principles were elucidated through computational simulations, and the mechanisms driving the enhancement in collection efficiency were explained.

Corrosion protection technology plays a crucial role in preserving infrastructure, ensuring safety and reliability, and promoting long-term sustainability. In this study, we combined experiments and various analyses to investigate the mechanism of corrosion occurring on the epoxy-based anticorrosive coating containing the additive of two-dimensional (2D) and water-stable zirconium-based metal - organic frameworks (Zr-MOFs). By using benzoic acid as the modulator for the growth of the MOF, a 2D MOF constructed from hexazirconium clusters and BTB linkers (BTB = 1,3,5-tri(4-carboxyphenyl)benzene) with coordinated benzoate (BA-ZrBTB) can be synthesized. By coating the BA-ZrBTB/epoxy composite film (BA-ZrBTB/EP) on the surface of cold-rolled steel (CRS), we found the lowest coating roughness (RMS) of BA-ZrBTB/EP is 2.83 nm with the highest water contact angle as 99.8°, which represents the hydrophobic coating surface. Notably, the corrosion rate of the BA-ZrBTB/EP coating is 2.28 × 10 -3 mpy, which is 4 orders of magnitude lower than that of the CRS substrate. Moreover, the energy barrier for oxygen diffusion through BA-ZrBTB/EP coating is larger than that for epoxy coating (EP), indicating improved oxygen resistance for adding 2D Zr-MOFs as the additive. These results underscore the high efficiency and potential of BA-ZrBTB as a highly promising agent for corrosion prevention in various commercial applications. Furthermore, this study represents the first instance of applying 2D Zr-MOF materials in anticorrosion applications, opening up new possibilities for advanced corrosion-resistant coatings.

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.

Ionogel-based sensors have gained widespread attention in recent years due to their excellent flexibility, biocompatibility, and multifunctionality. However, the adaptation of ionogel-based sensors in extreme environments (such as humid, acidic, alkaline, and salt environments) has rarely been studied. Here, thermoplastic polyurethane/carbon nanotubes-ionic liquids (TPU/CNTs-ILs) ionogels with a complementary sandpaper morphology on the surface were prepared by a solution-casting method with a simple sandpaper as the template, and the hydrophobic flexible TPU/CNTs-ILs ionogel-based sensor was obtained by modification using nanoparticles modified with cetyltrimethoxysilane. The hydrophobicity improves the environmental resistance of the sensor. The ionogel-based sensor exhibits multimode sensing performance and can accurately detect response signals from strain (0-150%), pressure (0.1-1 kPa), and temperature (30-100 °C) stimuli. Most importantly, the hydrophobic TPU/CNTs-ILs ionogel-based sensors can be used not only as wearable strain sensors to monitor human motion signals but also for information transfer, writing recognition systems, and underwater activity monitoring. Thus, the hydrophobic TPU/CNTs-ILs ionogel-based sensor offers a new strategy for wearable electronics, especially for applications in extreme environments.

Most hydrogels have poor mechanical properties, severely limiting their potential applications, and numerous approaches have been introduced to fabricate more robust and durable examples. However, these systems consist of nonbiodegradable polymers which limit their application in tissue engineering. Herein, we focus on the fabrication and investigate the influence of hydrophobic segments on ionic cross-linking properties for the construction of a tough, biodegradable hydrogel. A biodegradable, poly(γ-glutamic acid) polymer conjugated with a hydrophobic amino acid, l-phenylalanine ethyl ester (Phe), together with an ionic cross-linking group, alendronic acid (Aln) resulting in γ-PGA-Aln-Phe, was initially synthesized. Rheological assessments through time sweep oscillation testing revealed that the presence of hydrophobic domains accelerated gelation. Comparing gels with and without hydrophobic domains, the compressive strength of γ-PGA-Aln-Phe was found to be six times higher and exhibited longer stability properties in ethylenediaminetetraacetic acid solution, lasting for up to a month. Significantly, the contribution of the hydrophobic domains to the mechanical strength and stability of ionic cross-linking properties of the gel was found to be the dominant factor for the fabrication of a tough hydrogel. As a result, this study provides a new strategy for mechanical enhancement and preserves ionic cross-linked sites by the addition of hydrophobic domains. The development of tough, biodegradable hydrogels reported herein will open up new possibilities for applications in the field of biomaterials.

In this work, we demonstrate a simple, facile, and efficient one-pot synthesis of polymer–quantum dot nanocomposite films where nitrogen-doped graphene quantum dots (N-GQDs) were homogeneously dispersed in UV-curable, transparent polymer host matrix via the thiol–ene "click" reaction pathway. The highly fluorescent NOA–NGQD nanocomposite films exhibited strong hydrophobicity with water contact angle (>69°) owing to restructuring of the polymer chain networks. The various functional groups of the N-GQD surface, as carbonyl, amine, and hydroxyl groups, provided more interactive sites and low agglomeration to develop the strong electrostatic interactions between the NOA and N-GQDs, resulting in flexible NOA–NGQDs nanocomposites. Thus, obtained NOA–NGQD nanocomposites exhibited high transparency (>90%), low band-gap, and strong fluorescence spectral peak (>500 nm) after the homogeneous inclusion of N-GQDs in the NOA polymer matrix. This study paves the way to diverse applications of functionalized GQDs as well as transparent polymers for the development of hydrophobic polymer–QD nanocomposites by using UV catalyzed thiol–ene chemistry. Hence, as synthesized nanocomposite films would be widely applicable in flexible electronic display devices, light emitting diodes (LEDs), and optoelectronic applications. [ABSTRACT FROM AUTHOR]

The development of economic oil absorbents with selective wettability, high absorption rate, and recyclability is of great importance owing to the environmental pollution caused by oil spills. Herein, we present a facile strategy to grow one-dimensional (1D) hydrophobic silica via one-step chemical vapor deposition (CVD) of methyltrimethoxysilane (MTMS), catalyzed by ammonia at 100 °C. The final morphology (nanosphere, nanorod, or nanowire) of 1D silica was affected by the amount of precursor nanodroplet. The formation of 1D silica was attributed to the vapor–liquid–solid mechanism. In addition, the hydrophobic silica nanorods (SNRs) growing on the foam skeletons exhibited a vertical growth direction, contributing to the formation of superhydrophobic surface by constructing the roughness and tuning the surface energy. Therefore, the SNR-modified foams demonstrated ultralow density, superhydrophobicity, excellent fire resistance, and robust mechanical stability. Furthermore, they exhibited an excellent heat-resistant wettability up to 550 °C because of their vertical SNR arrays and hydrophobic methyl groups. Compared with other reported materials, the SNR-modified foams displayed great competitiveness with respect to the oil/water separation performances, including the absorption capacities and recyclability. The facile CVD method used to fabricate 1D silica provides a reference strategy for synthesizing other 1D materials. [ABSTRACT FROM AUTHOR]

It is imperative to induce hydrophilicity in intrinsically hydrophobic carbon nanotubes (CNTs) without losing their superior properties for applications that specifically deal with aqueous media. A method for transforming a CNTs sheet from hydrophobic to hydrophilic by treatment with N -methyl-2-pyrrolidone (NMP) is explored. The NMP-treated CNT sheets are assessed based on complementing characterization, and it is concluded that the binding of NMP to a CNTs surface is through noncovalent interaction without the incorporation of defects in CNTs. The induced hydrophilicity in the CNTs sheet is stable for water exposure over a longer duration while it displays a semireversible nature upon heat treatment. The mechanical and electrical properties of the NMP-treated CNTs sheet revealed enhancement in the tensile strength from 221 to 421 MPa while maintaining a good electrical conductivity of ∼1.22 × 10 4 S/m because of the improved interfacial properties. The hydrophilic CNTs exhibited excellent adsorption capacity for methylene blue dye. The NMP-treated CNTs sheets demonstrated their suitability in flexible hybrid supercapacitor (FHSC) devices with improved electrochemical performance with enhancement in the capacitance from 5.4 to 7.6 F/g and a decrease in the equivalent series resistance from 53 to 34 Ω compared to pristine CNTs-based devices. These solid-state FHSC devices displayed excellent cyclic charge-discharge performance along with robust behavior over thousands of bending cycles without significant performance degradation. The excellent dye removal capability and superior electrochemical performance of the NMP-treated CNTs sheet is a consequence of their improved interface with aqueous media, which is governed by the hydrophilic nature of the CNTs sheet.

The rapid development of artificial intelligent wearable devices has led to an increasing need for seamless information exchange between humans, machines, and virtual spaces, often relying on touch sensors as the primary interaction medium. Additionally, the demand for underwater detection technologies is on the rise owing to the prevalent wet and submerged environment. Here, a fiber-based capacitive sensor with superior stretchability and hydrophobicity is proposed, designed to cater to noncontact and underwater applications. The sensor is constructed using bacterial cellulose (BC)@BC/carbon nanotubes (CNTs) (BBT) helical fiber as the matrix and methyltrimethoxysilane (MTMS) as the hydrophobic modified agent, forming a hydrophobic silylated BC@BC/CNT (SBBT) helical fiber by the chemical vapor deposition (CVD) technique. These fibers exhibit an impressive contact angle of 132.8°. The SBBT helicalfiber-based capacitive sensor presents capabilities for both noncontact and underwater sensing, which exhibits a significant capacitance change of -0.27 (at a distance of 0.5 cm). We have achieved interactive control between real space and virtual space through intelligent data analysis technology with minimal interference from the presence of water. This work has laid a solid foundation of noncontact sensing with attributes such as degradability, stretchability, and hydrophobicity. Moreover, it offers promising solutions for barrier-free communication in virtual reality (VR) and underwater applications, providing avenues for smart human-machine interfaces for submerged use.

Flexible thermal radiation films with adjustable broad-band infrared radiation could maintain various heat-generating electronic devices working stably in corresponding operating temperatures, making them good candidates for radiative cooling (RC) material. However, the controllable radiation peaks of the metamaterial were narrow, and manipulation was a time-consuming and complex process. Herein, we design a simple TiN/Si bilayer film with controllable broad-band radiation peaks at a thermal radiation wavelength of 3.5-20 μm by impedance matching. Meanwhile, the different bilayer films applied to aluminum devices at different temperatures exhibit outstanding heat dissipation efficiency and maintain the corresponding equilibrium temperature to ensure that devices work stably for a long time. Moreover, the bilayer films deposited on the flexible PI substrates exhibit preferable thermostability and higher tensile strength than existing radiative cooling materials deposited on PDMS, PE, PMMA or TPX, etc. This work provides an effective strategy to realize efficient radiation cooling for flexible electronic devices and spacecraft appendages.

This study demonstrates a cost-effective, thin, multifunctional composite coating system with outstanding thermal insulation for thermal management and heat shield applications, such as roofs, as well as outstanding resistance to corrosion. The hydrophobic multifunctional epoxy composite coating systems were designed with surface-modified fillers to impart both reduced heat conduction and high infrared reflectance in a thin coating with a 65-100 μm dry film thickness (DFT). With a judicial combination of hollow microspheres (HMS) activated and modified with silica (sHMS) and stearic acid-modified TiO 2 (sMO), the developed composite coating attained the highest thermal insulation property with a temperature drop of 21-31 °C at different distances below the coated panel, which is superior to the values of temperature drop reported earlier. The high solar reflectance of the composite coating in the near-infrared (NIR) region exceeds 72% with a low thermal conductivity of 0.178 W m -1 K -1 . After 720 h of exposure in a 3.5 wt % NaCl solution, the composite coating revealed a corrosion protection efficiency of 99%. The work demonstrates that high solar reflectivity and low thermal conductivity must be active simultaneously to achieve superior thermal shielding in a thin coating on a metal. A careful selection of fillers and appropriate surface modifications ensures hydrophobicity and proper distribution of the fillers in the coating for a high barrier effect to prevent environmental deterioration. With these superior performance parameters, the developed composite coatings make an essential contribution to energy sustainability and the protection against environmental degradation.

We developed a novel hydrovoltaic power generator (HPG) using a Janus bilayer membrane with an asymmetric wettability. The Janus bilayer membrane was fabricated by stacking a hydrophobic graphene oxide (GO)-cellulose nanofiber (CNF) composite layer on a hydrophilic GO-CNF composite layer. Water supplied through the hydrophilic layer stops at the surface of the hydrophobic layer, producing separate wet and dry regions within the thin bilayer. Protons and sodium ions dissociate from oxygen-containing functional groups in the hydrophilic GO-CNF layer and migrate toward the hydrophobic layer, resulting in a maximum output voltage and current of 0.35 V and 20 μA, respectively, in deionized (DI) water. By replacement of DI water with a 0.6 M NaCl solution (i.e., the concentration of seawater), the output voltage and current were further increased to 0.55 V and 60 μA, respectively. This performance was consistent not only under low humidity due to the water supply but also under high humidity, where evaporation was restricted, indicating humidity-independent performance. The asymmetric wettability of the membrane remained stable throughout the experiment (7 days), enabling continuous power generation.

Cotton fibers have received considerable attention owing to their functional properties. Current research endeavors have shifted toward devising straightforward and versatile approaches for modifying cotton fibers. Herein, a simple and feasible method was proposed for preparing multifunctional cotton fibers. This method entailed subjecting cotton fibers to alkaline conditions, prompting the epoxy group in epoxidized soybean oil to engage in a ring-opening reaction with the hydroxyl group in cotton fibers and the amino group in polyhexamethylene guanidine hydrochloride. Epoxidized soybean oil acted as a bridge, forming a covalent bond between polyhexamethylene guanidine hydrochloride and cotton fibers, thereby facilitating the cationization of cotton fibers. Structural changes in the modified cotton fibers were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy. The modified cotton fibers were also evaluated for their dyeing, antibacterial, and hydrophobic properties. The results demonstrated that the dye exhaustion and total dye utilization of modified cotton in salt-free dyeing were much higher than those of raw cotton in conventional dyeing. The water contact angle of the modified cotton fiber reached 139.5°, and their antibacterial properties were partially improved. Importantly, this chemical modification was performed under mild conditions, highlighting its simplicity and environmentally friendly nature.

Water vapor condensation on hydrophobic surfaces has received much attention due to its ability to rapidly shed water droplets and enhance heat transfer, anti-icing, water harvesting, energy harvesting, and self-cleaning performance. However, the mechanism of heterogeneous nucleation on hydrophobic surfaces remains poorly understood and is attributed to defects in the hydrophobic coating exposing the high surface energy substrate. Here, we observe the formation of high surface energy nanoscale agglomerates on hydrophobic coatings after condensation/evaporation cycles in ambient conditions. To investigate the deposition dynamics, we studied the nanoscale agglomerates as a function of condensation/evaporation cycles via optical and field emission scanning electron microscopy (FESEM), microgoniometric contact angle measurements, nucleation statistics, and energy dispersive X-ray spectroscopy (EDS). The FESEM and EDS results indicated that the nanoscale agglomerates stem from absorption of sulfuric acid based aerosol particles inside the droplet and adsorption of volatile organic compounds such as methanethiol (CH3SH), dimethyl disulfide (CH3SSCH), and dimethyl trisulfide (CH3SSSCH3) on the liquid-vapor interface during water vapor condensation, which act as preferential sites for heterogeneous nucleation after evaporation. The insights gained from this study elucidate fundamental aspects governing the behavior of both short- and long-term heterogeneous nucleation on hydrophobic surfaces, suggest previously unexplored microfabrication and air purification techniques, and present insights into the challenges facing the development of durable dropwise condensing surfaces. [ABSTRACT FROM AUTHOR]

Edged-selectively fluorine (F) functionalized graphene nanoplatelets (EFGnPs-F) with a p-i-n structure of perovskite solar cells achieved 82% stability relative to initial performance over 30 days of air exposure without encapsulation. The enhanced stability stems from F-substitution on EFGnPs; fluorocarbons such as polytetrafluoroethylene are well-known for their superhydrophobic properties and being impervious to chemical degradation. These hydrophobic moieties tightly protect perovskite layers from air degradation. To directly compare the effect of similar hydrophilic graphene layers, edge-selectively hydrogen functionalized graphene nanoplatelet (EFGnPs-H) treated devices were tested under the same conditions. Like the pristine MAPbI3 perovskite devices, EFGnPs-H treated devices were completely degraded after 10 days. The hydrophobic properties of EFGnPs-F were characterized by contact angle measurement. The test results showed great water repellency compared to pristine perovskite films or EFGnPs-H coated films. This resulted in highly air-stable p-i-n perovskite solar cells. [ABSTRACT FROM AUTHOR]

4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) is one of the most promising herbicide targets for the development of agricultural chemicals owing to its unique mechanism of action in plants. We previously reported on the co-crystal structure of Arabidopsis thaliana ( At ) HPPD complexed with methylbenquitrione ( MBQ ), an inhibitor of HPPD that we previously discovered. Based on this crystal structure, and in an attempt to discover even more effective HPPD-inhibiting herbicides, we designed a family of triketone-quinazoline-2,4-dione derivatives featuring a phenylalkyl group through increasing the interaction between the substituent at the R 1 position and the amino acid residues at the active site entrance of At HPPD. Among the derivatives, 6-(2-hydroxy-6-oxocyclohex-1-ene-1-carbonyl)-1,5-dimethyl-3-(1-phenylethyl)quinazoline-2,4(1H,3H)-dione ( 23 ) was identified as a promising compound. The co-crystal structure of compound 23 with At HPPD revealed that hydrophobic interactions with Phe392 and Met335, and effective blocking of the conformational deflection of Gln293, as compared with that of the lead compound MBQ , afforded a molecular basis for structural modification. 3-(1-(3-Fluorophenyl)ethyl)-6-(2-hydroxy-6-oxocyclohex-1-ene-1-carbonyl)-1,5-dimethylquinazoline-2,4(1H,3H)-dione ( 31 ) was confirmed to be the best subnanomolar-range At HPPD inhibitor (IC 50 = 39 nM), making it approximately seven times more potent than MBQ . In addition, the greenhouse experiment showed favorable herbicidal potency for compound 23 with a broad spectrum and acceptable crop selectivity against cotton at the dosage of 30-120 g ai/ha. Thus, compound 23 possessed a promising prospect as a novel HPPD-inhibiting herbicide candidate for cotton fields.

We report that the carborane-based metal-organic framework (MOF) m CB-MOF-1 can achieve high adsorptive selectivity for CO 2 mixtures. This hydrophobic MOF presenting open metal sites shows high CO 2 mixtures. This hydrophobic MOF presenting open metal sites shows high CO 2 adsorption capacity and remarkable selectivity values that are maintained even under extremely humid conditions. The comparison of m CB-MOF-1' with MOF-74(Ni) demonstrates the superior performance of the former under challenging moisture operation conditions.

This work explores the energetics of intermolecular H-bonds inside a hydrophobic protein cavity. Kinetic measurements were performed on the gaseous deprotonated ions (at the −7 charge state) of complexes of bovine β-lactoglobulin (Lg) and three monohydroxylated analogs of palmitic acid (PA): 3-hydroxypalmitic acid (3-OHPA), 7-hydroxypalmitic acid (7-OHPA), and 16-hydroxypalmitic acid (16-OHPA). From the increase in the activation energy for the dissociation of the (Lg + X-OHPA) ions, compared with that of the (Lg + PA) ion, it is concluded that the -OH groups of the X-OHPA ligands participate in strong (5 - 11 kcal mol) intermolecular H-bonds in the hydrophobic cavity of Lg. The results of molecular dynamics (MD) simulations suggest that the -OH groups of 3-OHPA and 16-OHPA act as H-bond donors and interact with backbone carbonyl oxygens, whereas the -OH group of 7-OHPA acts as both H-bond donor and acceptor with nearby side chains. The capacity for intermolecular H-bonds within the Lg cavity, as suggested by the gas-phase measurements, does not necessarily lead to enhanced binding in aqueous solution. The association constant (K) measured for 7-OHPA [(2.3 ± 0.2) × 10 M] is similar to the value for the PA [(3.8 ± 0.1) × 10 M]; K for 3-OHPA [(1.1 ± 0.3) × 10 M] is approximately three-times larger, whereas K for 16-OHPA [(2.3 ± 0.2) × 10 M] is an order of magnitude smaller. Taken together, the results of this study suggest that the energetic penalty to desolvating the ligand -OH groups, which is necessary for complex formation, is similar in magnitude to the energetic contribution of the intermolecular H-bonds. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Developing active and selective catalysts that convert CO 2 into valuable products remains a critical challenge for further application of the electrochemical CO 2 reduction reaction (CO 2 RR). Catalytic tuning with organic additives/films has emerged as a promising strategy to tune CO 2 RR activity and selectivity. Herein, we report a facile method to significantly change CO 2 RR selectivity and activity of copper and gold electrodes. We found improved selectivity toward HCOOH at low overpotentials on both polycrystalline Cu and Au electrodes after chemical modification with a poly(4-vinylpyridine) (P4VP) layer. In situ attenuated total reflection surface-enhanced infrared reflection-adsorption spectroscopy and contact angle measurements indicate that the hydrophobic nature of the P4VP layer limits mass transport of HCO 3 - and H 2 O, whereas it has little influence on CO 2 mass transport. Moreover, the early onset of HCOOH formation and the enhanced formation of HCOOH over CO suggest that P4VP modification promotes a surface hydride mechanism for HCOOH formation on both electrodes.

The accelerated evolution of the Internet of Things has brought new challenges to the gas sensors, which are required to work persistently under harsh conditions, like high humidity. However, currently, it is quite challenging to solve the hindrance of the trade-off between gas-sensing performance and anti-humidity ability of the chemiresistive gas sensors. Herein, hydrophobic inorganic CeO 2 /SnO 2 heterostructure films were prepared by depositing the CeO 2 layers with a thickness of a few nanometers onto the SnO 2 film via a magnetron sputtering method. The sensors based on the CeO 2 /SnO 2 heterostructure films demonstrated excellent gas-sensing performance toward trimethylamine (TEA) with high response, wide detection range (0.04-500 ppm), low record detection limit (0.04 ppm), ideal reproducibility, and long-term stability, while concurrently possessing promising anti-humidity ability. A portable, wireless TEA-sensing system containing the CeO 2 /SnO 2 sensor was constructed to realize the real-time monitoring of trace concentration of the volatiles released from a fish. This work provides a novel strategy to prepare advanced chemiresistive gas sensors for humidity-independent detection of harmful gases and vapors and will accelerate their commercialization process in the field of food safety and public health.

Highly connected metal organic frameworks (MOFs) in which at least one building block has connectivity higher than twelve are very rare and much desirable. We report here the first examples of isostructural 14-connected MOFs, RE- frt -MOF-1, constructed from the assembly of 14-c hexanuclear rare-earth clusters, [RE 6 (μ 3 -X) 8 (COO) 12 ] 2- (RE: Y 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Yb 3+ and X: OH - /F - ) with a tritopic carboxylate-based organic linker. This linker serves as a 3-c and 4-c organic node resulting in the formation of a unique, trinodal (3,4,14)-c framework. RE- frt -MOF-1 are stable in air and alkaline aqueous solutions and show an intriguingly continuous, reversible breathing behavior, between a wide and a narrow-pore phase, upon guest removal. Crystallinity is retained during breathing, and single-crystal X-ray diffraction shed light into the associated structural transformation. Vapor sorption studies performed on Y- frt -MOF-1 revealed a high affinity for non-polar vapors such as n -hexane, cyclohexane, and benzene, displaying type I isotherms with high uptake at low relative pressures (<10 -3 p ), associated with the hydrophobic nature of the 1D channels and also with their rhombic shape. In contrast, polar vapors such as acetonitrile and ethanol show type V isotherms due to favorable vapor-vapor interactions. Notably these vapors, except cyclohexane, trigger the transition from the narrow to the wide pore phase, accompanied by a remarkable increase in uptake, reaching 70.6, 109, 100.4, and 87.7% for p 0 ), associated with the hydrophobic nature of the 1D channels and also with their rhombic shape. In contrast, polar vapors such as acetonitrile and ethanol show type V isotherms due to favorable vapor-vapor interactions. Notably these vapors, except cyclohexane, trigger the transition from the narrow to the wide pore phase, accompanied by a remarkable increase in uptake, reaching 70.6, 109, 100.4, and 87.7% for n -hexane, benzene, acetonitrile, and ethanol, respectively.

Creating thin (<100 nm) hydrophobic coatings that are durable in wet conditions remains challenging. Although the dropwise condensation of steam on thin hydrophobic coatings can enhance condensation heat transfer by 1000%, these coatings easily delaminate. Designing interfaces with high adhesion while maintaining a nanoscale coating thickness is key to overcoming this challenge. In nature, cell membranes face this same challenge where nanometer-thick lipid bilayers achieve high adhesion in wet environments to maintain integrity. Nature ensures this adhesion by forming a lipid interface having two nonpolar surfaces, demonstrating high physicochemical resistance to biofluids attempting to open the interface. Here, developing an artificial lipid-like interface that utilizes fluorine-carbon molecular chains can achieve durable nanometric hydrophobic coatings. The application of our approach to create a superhydrophobic material shows high stability during jumping-droplet-enhanced condensation as quantified from a continual one-year steam condensation experiment. The jumping-droplet condensation enhanced condensation heat transfer coefficient up to 400% on tube samples when compared to filmwise condensation on bare copper. Our bioinspired materials design principle can be followed to develop many durable hydrophobic surfaces using alternate substrate-coating pairs, providing stable hydrophobicity or superhydrophobicity to a plethora of applications.

Fibrous surfaces in nature have already exhibited excellent functions that are normally ascribed to the synergistic effects of special structures and material properties. The honey bee tongue, foraging liquid food in nature, has a unique segmented surface covered with dense hairs. Since honey bees are capable of using their tongue to adapt to possibly the broadest range of feeding environments to exploit every possible source of liquids, the surface properties of the tongue, especially the covering hairs, would likely represent an evolutionary optimization. In this paper, we show that their tongue hairs are stiff and hydrophobic, the latter of which is highly unexpected as the structure is designed for liquid capturing. We found that such hydrophobicity can prevent those stiff hairs from being adhered to the soft tongue surface, which could significantly enhance the deformability of the tongue when honey bees feed at various surfaces and promote their adaptability to different environments. These findings bridge the relationship between surface wettability and structural characteristics, which may shed new light on designing flexible microstructured fiber systems to transport viscous liquids.

Electrochemical CO 2 reduction can convert waste emissions into dense liquid fuels compatible with existing energy infrastructure. High-rate electrocatalytic conversion of CO 2 to ethanol has been achieved in membrane electrode assembly (MEA) electrolyzers; however, ethanol produced at the cathode is transported, via electroosmotic drag and diffusion, to the anode, where it is diluted and may be oxidized. The ethanol concentrations that result on both the cathodic and anodic sides are too low to justify the energetic and financial cost of downstream separation. Here, we present a porous catalyst adlayer that facilitates the evaporation of ethanol into the cathode gas stream and reduces the water transport, leading to a recoverable stream of concentrated ethanol. The adlayer is comprised of ethylcellulose-bonded carbon nanoparticles and forms a porous, electrically conductive network on the surface of the copper catalyst that slows the transport of water to the gas channel. We achieve the direct production of an ethanol stream of 12.4 wt %, competitive with the concentration of current industrial ethanol production processes.

Membrane distillation (MD) is a promising technology for the treatment of high salinity wastewater using a hydrophobic membrane; however, the occurrence of wetting due to surfactants in polluted or low surface tension liquid impedes MD application. Common monitoring approaches, such as conductivity and flux measurement, cannot explain the wetting phenomenon that occurs during the wetting process in detail. Recently, impedance spectroscopy has been proposed for early wetting detection, as it depends on the change of water/air composition in the membrane pores. An earlier and larger variation was observed with precise signal detection. In this study, we proposed an analytical approach to estimate the wetting front, which is the average feed intrusion distance, by the impedance value recorded in real-time operation. With this proposed approach, the wetting mechanism in the presence of a surfactant and the effect of pore size on a commercial polyvinylidene fluoride membrane could be quantified, which cannot be explained in detail using conductivity and flux measurements.

Triboelectric nanogenerators (TENGs) are useful for harvesting clean and widely distributed water droplet energy with high efficiency. However, the commonly used polymer films in TENGs for water droplet energy harvesting have the disadvantages of poor breathability, poor skin affinity, and irreparable hydrophobicity, which greatly hinder their wearable uses. Here, we report an all-fabric TENG (F-TENG), which not only has good air permeability and hydrophobic self-repairing properties but also shows effective energy conversion efficiency. The hydrophobic surface composed of SiO 2 nanoparticles and poly(vinylidenefluoride- co -hexafluoropropylene)/perfluorodecyltrichlorosilane (PVDF-HFP/FDTS) exhibits a static contact angle of 157° and displays excellent acid and alkali resistance. Because of its low glass transition temperature, PVDF-HFP can facilitate the movement of FDTS molecules to the surface layer under heating conditions, realizing hydrophobic self-repairing performance. Furthermore, with the optimized compositions and structure, the water droplet F-TENG shows 7-fold enhancement of output voltage compared with the conventional single-electrode mode TENG, and a total energy conversion efficiency of 2.9% is achieved. Therefore, the proposed F-TENG can be used in multifunctional wearable devices for raindrop energy harvesting.

Photothermally assisted superhydrophobic sponges play a vital role in the fields of waste oil collection, oil purification, and solar desalination. However, the widely reported superhydrophobic sponges with photothermal efficiency usually suffer from a post-/premodification process of harmful materials, high loading content of photothermal agents, and low photothermal efficiency. Herein, an MXene-based melamine sponge (MS) was facilely fabricated by hydrogen bonding interaction between the amino groups on the skeleton of the MS and the polar groups on the surface of the as-exfoliated 2D MXene Ti 3 C 2 T x nanosheets. Interestingly, the as-fabricated MXene sponge exhibits excellent hydrophobicity and high photothermal efficiency under an extremely low loading of MXene Ti 3 C 2 T x nanosheets (0.1 wt %). Moreover, the highly hydrophobic sponge also possesses a high oil absorption capacity as high as 176 times of its own weight and keeps stable under multiple absorption/desorption cycling tests. Surprisingly, the surface temperature of the MXene sponge can quickly reach 47 °C under illumination and has good reproducibility during multiple light on/off cycles. The excellent photothermal performance and large oil absorption capacity of the MXene sponge endow the highly hydrophobic sponge with fast solvent evaporation speed and high-purity waste oil collection (99.7 wt % dichloromethane) under illumination, which holds great promise for oil/water separation, leaked oil collection, and photo-driven waste oil collection and purification applications. It is envisioned that this work can open a new strategy for new designs of 3D multifunctional sponges for high-performance waste oil collection and purification.

Herein, we successfully synthesized high-quality Hf-ZnO thin films with various Hf contents (0, 3, 6, 9, 12, and 15 at. %), which showed both superhydrophilic (6% Hf-ZnO) and ultrahydrophobic (15% Hf-ZnO) wetting behavior. Different characterization methods were opted to recognize the structural (XRD, SEM, AFM) and defect properties (XPS) of the pristine and doped materials, to understand the mechanisms underlying the tuning of wetting behavior (contact angle). Hafnium doping plays a noteworthy role in tuning the morphology of the ZnO nanostructures, roughness of the material surface, generation of defects, Lewis acid-base interactions, and wettability properties. We achieved a superhydrophilic surface with 6% Hf-ZnO owing to a smooth surface, less basicity, and maximum concentration of oxygen vacancies, and also an ultrahydrophobic surface with 15% Hf-ZnO because of the rough surface, high basicity, and minimum concentration of oxygen vacancies. The as prepared Hf-ZnO samples showed stable performance (stability, wearability, weatherability, and antifouling) under real-life conditions marking them multifunctional and biosafe material to be effectively used in solar and building's window. A wetting mechanism was established to relate the wetting behavior of the samples to oxygen vacancies (active sites for water dissociation: resulted due to charge mismatch of host cation (Zn 2+ ) by the doped cation (Hf 4+ )), roughness (smooth surface (Wenzel) with minimum R rms (2.522) portraying hydrophobic property), basicity (H R rms (2.522) portraying hydrophobic property), basicity (H 2 O: Lewis Base; ZnO: Lewis acid; HfO 2 : Lewis base) and morphology (tube-like structure (0-6% Hf-ZnO) and caltrop-like structure (12-15% Hf-ZnO)).

Exploring novel p -hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) inhibitors has become one of the most promising research directions in herbicide innovation. On the basis of our tremendous interest in exploiting more powerful HPPD inhibitors, we designed a family of benzyl-containing triketone-aminopyridines via a structure-based drug design (SBDD) strategy and then synthesized them. Among these prepared derivatives, the best active 3-hydroxy-2-(3,5,6-trichloro-4-((4-isopropylbenzyl)amino)picolinoyl)cyclohex-2-en-1-one ( 23 , IC 50 = 0.047 μM) exhibited a 5.8-fold enhancement in inhibiting Arabidopsis thaliana ( At ) HPPD activity over that of commercial mesotrione (IC 50 = 0.273 μM). The predicted docking models and calculated energy contributions of the key residues for small molecules suggested that an additional π-π stacking interaction with Phe-392 and hydrophobic contacts with Met-335 and Pro-384 were detected in At HPPD upon the binding of the best active compound 23 compared with that of the reference mesotrione. Such a molecular mechanism and the resulting binding affinities coincide with the proposed design scheme and experimental values. It is noteworthy that inhibitors 16 (3-hydroxy-2-(3,5,6-trichloro-4-((4-chlorobenzyl)amino)picolinoyl)cyclohex-2-en-1-one), 22 (3-hydroxy-2-(3,5,6-trichloro-4-((4-methylbenzyl)amino)picolinoyl)cyclohex-2-en-1-one), and 23 displayed excellent greenhouse herbicidal effects at 150 g of active ingredient (ai)/ha after postemergence treatment. Furthermore, compound 16 showed superior weed-controlling efficacy against Setaria viridis ( S. viridis ) versus that of the positive control mesotrione at multiple test dosages (120, 60, and 30 g ai/ha). These findings imply that compound 16 , as a novel lead of HPPD inhibitors, possesses great potential for application in specifically combating the malignant weed S. viridis .

A superflexible hydrophobic silica-based aerogel (FHSA) was prepared via a facile sol-gel process and ambient pressure drying method. The FHSA was treated at different temperatures varying from -196 to 450 °C to evaluate its thermal and mechanical performances. The evolutions of the physical property, hydrophobicity, microstructure, pore structure, and chemical structure of the FHSA with the various treatment temperatures were investigated comprehensively. The structure of the FHSA did not show an obvious change after treatment in the liquid nitrogen. The bulk density of the FHSA increased from 0.047 to 0.077 g cm -3 when the thermal treatment temperature increased from 25 to 450 °C. The specific surface area and pore volume of the FHSA increased with the treatment temperature owing to the decomposition of the organic moieties. The Fourier transform infrared spectra showed that the methyl groups in the FHSA had excellent thermostability up to 400 °C. The water contact angles of the FHSA after treatment at -196, 25, 200, 300, 350, 400, and 450 °C were 131, 151, 162, 150, 132, 119, and 34°, respectively. The thermal conductivity of the FHSA at a low temperature of -10 °C was 0.022 W m -1 K -1 . The reversible deformation rate of the FHSA was more than 80% within 100 compression cycles. After treatment in liquid nitrogen, the reversible deformation rate of the FHSA remained at 50%. The synthesis method of the FHSA is simple, the resulting FHSA showed good performance both in thermostability and flexibility, and it is promisingly applied for thermal insulation and sealing in ultralow-temperature environments.

This study aimed to assess the effect of tannin molecular mass on nonbleachable pigment formation and subsequent stability under wine-like conditions. Tannin fractions of a defined molecular mass range were prepared from grape skins and seeds and reacted with malvidin-3-glucoside for 120 days in three media types: chemically defined wine media with or without acetaldehyde addition or model wine without acetaldehyde. Precipitation was observed after the reaction period and increased in response to both higher tannin molecular mass and acetaldehyde concentration. To confirm whether acetaldehyde-mediated condensation of tannin and anthocyanin modified the solubility of the nonbleachable pigments formed, HPLC-MS was used for the semiquantitative identification of vinyl derivatives and ethyl-linked adducts in soluble and precipitated materials. It was found that the proportion of vinyl derivatives and ethyl-linked anthocyanin was elevated in tannin precipitates relative to soluble pigmented material. Despite substantial losses of tannin due to precipitation, the resulting nonbleachable pigment concentration and color intensity were higher in wine media containing elevated acetaldehyde, when each tannin size category was considered independently. The results of this study indicated that the development of nonbleachable pigments from larger tannins may be limited when acetaldehyde-mediated condensation with anthocyanin predominates in wine, concomitant with precipitation.

Introducing nonvolatile liquid acids into porous solids is a promising solution to construct anhydrous proton-conducting electrolytes, but due to weak coordination or covalent bonds building these solids, they often suffer from structural instability in acidic environments. Herein, we report a series of steady conjugated microporous polymers (CMPs) linked by robust alkynyl bonds and functionalized with perfluoroalkyl groups and incorporate them with phosphoric acid. The resulting composite electrolyte exhibits high anhydrous proton conductivity at 30-120 °C (up to 4.39 × 10 -3 S cm -1 ), and the activation energy is less than 0.4 eV. The excellent proton conductivity is attributed to the hydrophobic pores that provide nanospace for continuous proton transport, and the hydrogen bonding between phosphoric acid and perfluoroalkyl chains of CMPs promotes short-distance proton hopping from one side to the other.

In this paper, we demonstrate the ability to fabricate temperature sensors by using our newly developed carbon nanotube-graphene oxide (CNT-GO) ink to print temperature-sensitive traces on highly flexible, thin, and adhesive PET (polyethylene terephthalate) tapes, which in turn are integrated on surfaces of different curvatures and wettabilities. Therefore, the strategy provides a facile, low-cost, and environmentally friendly method to deploy printed temperature sensors on surfaces of widely varying curvatures and wettabilities. The temperature sensing occurs through a thermally induced change in the resistance of the printed traces and we quantify the corresponding negative temperature coefficient of resistance (α) for different conditions of curvatures and wettabilities. In addition, we identify that at low temperatures (below 15 °C), the printed traces show an α value that can be as large (in magnitude) as 60 × 10 -3 /°C, which is several times higher than the typical α values reported for temperature sensors fabricated with CNT or other materials. Furthermore, we achieve the printing of traces that are only 1-3 μm thick on a 50 μm-thick PET film: therefore, our design represents an ultrathin additively fabricated temperature sensor that can be easily integrated for wearable electronic applications. Finally, we show that despite being subjected to repeated temperature cycling, there is little degradation of the CNT-GO microarchitectures, making these printed traces capable of repeated uses as potential temperature sensors.

Two physical properties in polymers, hydrophobic and water-absorptive, are known to be incompatible. However, human skin in nature has a hydrophobic surface and yet absorbs water throughout hydrophilic amino acid sequences in filaggrin, one of the abundant proteins in our outermost skin layer. Although present in nature, a hydrophilic path network in a hydrophobic polymer is difficult to synthesize because of poor wettability and immiscibility between the two types of materials. Herein, we introduce a novel method for the creation of a hydrophobic absorptive polymer (HPHG), which overcomes the inherent incompatibility by increasing hydrophobicity of reaction sites in hydrophilic monomers. The methacrylate structure in hydrophilic monomers successfully contributes to stabilize reverse emulsions, which consist of polyethyleneglycol (PEG) methacrylate and polyethyleneglycol (PEG) dimethacrylate, in a hydrophobic matrix of polymethylhydrosiloxane and divinylpolydimethylsiloxane (PDMS material sources). The HPHG film (with a 11 weight percent water content) shows water repellency having over 100° contact angle with a water droplet and yet is capable of absorbing water by 19.1 weight percent while maintaining decent hydrophobicity on the surface (78° water contact angle). We have successfully demonstrated a moisture-driven actuator by constructing a bilayer of HPHG and PDMS (or a textile), which is delamination-free and transforms into a curvature geometry by a preferential expansion of the HPHG layer. HPHG is applicable for soft robotics and smart actuators where a hydrophobic artificial skin is needed to protect the surface against hydrophilic invasions of undesirable substances such as metal ions, bacteria, or viruses but absorptive for desirable evaporation and mobility by water migration in the polymer matrix.

Hydrophobic coatings with low thermal resistance promise a significant enhancement in condensation heat transfer performance by promoting dropwise condensation in applications including power generation, water treatment, and thermal management of high-performance electronics. However, after nearly a century of research, coatings with adequate robustness remain elusive due to the extreme environments within many condensers and strict design requirements needed to achieve enhancement. In this work, we enable long-lasting condensation heat transfer enhancement via dropwise condensation by infusing a hydrophobic polymer, Teflon AF, into a porous nanostructured surface. This polymer infused porous surface (PIPS) uses the large surface area of the nanostructures to enhance polymer adhesion, while the nanostructures form a percolated network of high thermal conductivity material throughout the polymer and drastically reduce the thermal resistance of the composite. We demonstrate over 700% enhancement in the condensation of steam compared to an uncoated surface. This performance enhancement was sustained for more than 200 days without significant degradation. Furthermore, we show that the surfaces are self-repairing upon raising the temperature past the melting point of the polymer, allowing recovery of hydrophobicity and offering a level of durability more appropriate for industrial applications.

Inspired by nature, Janus membranes with unidirectional liquid transport (ULT) were developed to be used in the fields of fog collection, moisture-wicking fabrics, demulsification, etc. However, the obtained Janus membranes are often unifunctional, and it is still a great challenge to adjust the ULT of Janus membranes for multifunctional applications. Herein, a scalable, low-cost, and machine-washable Janus membrane was developed by combining the cyclic self-assembly of phytic acid and Fe III and a one-side spraying coating of poly(dimethylsiloxane) (PDMS), featuring adjustable ULT upon challenge for multifunctional applications. By controlling the amount of PDMS, the Janus membranes exhibit two different performances, ULT and switchable permeation. The prepared Janus membranes achieved an excellent moisture-wicking fabric (1.6× the water evaporation rate of cotton), fast water collection under oil, rapid demulsification, and the efficient separation of an oil/water mixture. The separation efficiency of a light or heavy oil from water was higher than 99.9% even after 10 separation cycles, and the flux of the separation was up to 2.55 × 10 4 or 2.38 × 10 4 L m -2 h -1 , respectively. This study could provide an idea for the development of more Janus membranes with adjustable performances to realize multifunctional applications.

Most materials used for optical lighting applications need to produce a uniform illumination and require high mechanical and hydrophobic properties. However, they are rarely eco-friendly. Herein, a bio-based, polymer matrix-free, luminescent, and hydrophobic film with excellent mechanical properties for optical lighting purposes is demonstrated. A template is prepared by turning a wood veneer into porous scaffold from which most of the lignin and half of the hemicelluloses are removed. The infiltration of quantum dots (CdSe/ZnS) into the porous template prior to densification resulted in almost uniform luminescence (isotropic light scattering) and could be extended to various quantum dot particles, generating different light colors. In a subsequent step, the luminescent wood film is coated with hexadecyltrimethoxysilane (HDTMS) via chemical vapor deposition. The presence of the quantum dots coupled with the HDTMS coating renders the film hydrophobic (water contact angle ≈ 140°). This top-down process strongly eliminates lumen cavities and preserves the orientation of the original cellulose fibrils to create luminescent and polymer matrix-free films with high modulus and strength in the direction of fibers. The proposed optical lighting material could be attractive for interior designs ( e.g ., lamps and laminated cover panels), photonics, and laser devices.