Superhydrophobic Modification Research Articles

Optimization of durable superhydrophobic wood with superstrong ultraviolet resistance and chemical stability

The less UV durability and weak chemical stability of superhydrophobic wood limited its wide application. Cu2(OH)3Cl nano particles, epoxy (EP), vinyltriethoxysilane (VTES), and room temperature vulcanized silicone rubber (RTV) were combined together to modify both soft and hard wood with function of superhydrophobic at once successfully. The modified wood was endowed not only superhydrophobicity as expected, such as CA more than 150°, along with anti-fouling and self-cleaning properties, but also excellent durability, including well chemical, sandpaper abrasion, water impact and tape peeling stability. Most prominently, there was almost no color changing being observed on the modified samples. Furthermore, the best UV resistance, 3168 h consistently against UV irradiation, was achieved in the field of wood superhydrophobic modification. The proposed synergistic protective mechanism by synthesizing silicon dioxide and siloxane has potential to extend the service life and improve the high value utilization of wood product.

Fabrication of multi-functional and breathable superhydrophobic cotton fabric based on curcumin/ZIF-8 through mild thiol-ene click chemistry reaction

Multifunctional superhydrophobic materials demonstrate remarkable performance and promising application prospects in various fields. However, there is still considerable interest in developing milder superhydrophobic modification techniques for materials. In this study, we aimed to improve the surface roughness of cotton fabric by utilizing an in-situ growth method to incorporate zeolitic imidazolate framework-8 (ZIF-8). The fabric underwent a subsequent treatment with curcumin at room temperature, which served as a bridge for connection and provided multifunction to form a core–shell structure (curcumin/ZIF-8). Eventually, by implementing a mild thiol-ene click chemistry reaction, specifically by grafting octadecanethiol onto the C = C bond within the curcumin structure, we successfully prepared superhydrophobic modified cotton fabric known as SHCZC. The contact angle of the SHCZC material reached 168.7°, accompanied by a sliding angle of just 1°. Furthermore, SHCZC exhibited exceptional stability in harsh environments, enduring exposure to strong acids, alkalis, organic solvents, high and low temperatures, repeated washing, and abrasion. The material also demonstrated excellent thermal stability and remarkable breathability. Additionally, SHCZC possessed self-cleaning, UV-blocking, anti-fouling, antibacterial, anti-icing, and oil/water separation characteristics. The presence of these characteristics expands the potential of SHCZC beyond the field of superhydrophobic materials, positioning it as a highly advanced and versatile multifunctional material.

Fabrication of multifunctional cotton fabric with “pompon mum” shaped surface by ZIF-8 for applications in oil-water separation and anti-icing

The application of metal organic framework materials (MOFs) in superhydrophobic modification has a broad prospect. In this work, a multifunctional flexible superhydrophobic cotton fabric (PSZDC) with no fluorine, high oil-water separation efficiency, and excellent anti-icing performance was prepared through the modification of cotton fabric by dopamine (DA), ZIF-8, stearic acid (SA) and polydimethylsiloxane (PDMS). SEM and 3D ultra-depth of field stereo microscope results revealed the unique “pompon mum” shaped surface of PSZDC. ATR-FTIR, XRD, and XPS analyses confirmed the composition of the hydrophobic layer. PSZDC had a water contact angle of 165.4° and showed stability in mechanical robustness and chemical resistance tests. The oil-water separation efficiency of PSZDC was close to 100 %, and the permeation flux was as high as 36,000 (L·m−2h−1). PSZDC also exhibited excellent effect in anti-icing test, which was expected to be used as ice rescue suits and oil-water separation materials. In addition, this method was universal and repeatable, as evidenced by its application to four common fabrics: nylon-6, polyester, wool, and silk.

Janus polyurethane sponge as an antibiofouling, antibacterial, and exudate-managing dressing for accelerated wound healing.

The non-fouling condition, bacteria-free environment and suitable moisture at wound site are crucial for chronic wound healing. However, it remains highly meaningful yet challenging to develop wound dressings that can simultaneously achieve these desirable functions. In this work, a kind of multifunctional Janus polyurethane sponge (Janus-PU) was designed and fabricated by coating near-infrared (NIR)-responsive and superhydrophobic nanoparticles (F-ZnO@Ag NPs) on one surface of sponge. The nano-functionalized outer layer can endow Janus-PU with superhydrophobic antifouling property for preventing bacterial colonization and broad-spectrum antibacterial activity due to the presence of Ag NPs. Especially, the synergistic combination of asymmetric structure and strong NIR photothermal effect can impart Janus-PU with NIR-controlled unidirectional exudate removal, thus achieving an optimal wetting environment for wound healing. The mice full-thickness skin acute wounds treated with Janus-PU under NIR irradiation showed superior anti-infection and healing effect compared to the commercial dressings. Significantly, the treatment using Janus-PU with NIR irradiation can accelerate the recovery of methicillin-resistantStaphylococcus aureus(MRSA)-infected diabetic chronic wounds due to the synergistic effect of antibiofouling, antibacterial and exudate-managing. The Janus-PU as a promising multifunctional dressing can prevent bacterial invasion and create an appropriate environment for wound healing, providing an effective solution for intractable wounds and infections. STATEMENT OF SIGNIFICANCE: The development of advanced wound dressings to ensure non-fouling condition, bacteria-free environment and suitable moisture is crucial for chronic wound healing. However, it remains a considerable challenge to simultaneously integrate antibiofouling, antibacterial and exudate-managing properties into a single dressing. In this work, we developed a kind of multifunctional Janus polyurethane sponge (Janus-PU) by a single-sided superhydrophobic modification strategy, which can simultaneously achieve superhydrophobic antifouling property, effective broad-spectrum antibacterial and near-infrared controlled exudate removal. The Janus-PU designed herein can not only create an optimal environment for accelerated wound healing, but also avoid frequent dressing replacement, thus providing an ideal material system for intractable wounds and infections.

Hydrophilic silica transformed silicone rubber into Superhydrophobic composites

AbstractSilicone rubber is widely used in medical and equipment manufacturing fields due to its excellent sealing and solvent resistance. However, the hydrophobicity of silicone rubber was unsatisfactory for many advanced engineering structures and applications. Generally, the preparation of artificial superhydrophobic materials suffered from either complicated in process or poor in environmental protection. Here, we reported a simple method to prepare silicone rubber composites with excellent superhydrophobic properties (water contact angle [WCA] = 155.2°) from low‐cost hydrophilic silica. Tests showed that the uniform micro‐nano structures were the key to the superhydrophobic properties of silicone rubber composites. The bounce test observed the rebound of water droplets with different initial velocities (0.77, 1, and 2 m/s) impacting silicone rubber surface, and verified the great advantages of silicone rubber modified by silica in hydrophobic. The modification method shown in this work provides a simple way to manufacture non‐fluorinated, robustness superhydrophobic surfaces for a wide range of potential applications.Highlights Based on the improvement of micro‐nano structure of the matrix surface by industrial silica, the preparation of superhydrophobic silicone rubber composites was realized. A process method for preparing fluorine‐free superhydrophobic silicone rubber composites from hydrophilic silica was proposed. Stretchability and robustness were the key factors for successful superhydrophobic modification of silicone rubber elastomers.

Superhydrophobic Surface Modification of Polymer Microneedles Enables Fabrication of Multimodal Surface-Enhanced Raman Spectroscopy and Mass Spectrometry Substrates for Synthetic Drug Detection in Blood Plasma.

Microneedles are widely used substrates for various chemical and biological sensing applications utilizing surface-enhanced Raman spectroscopy (SERS), which is indeed a highly sensitive and specific analytical approach. This article reports the fabrication of a nanoparticle (NP)-decorated microneedle substrate that is both a SERS substrate and a substrate-supported electrospray ionization (ssESI) mass spectrometry (MS) sample ionization platform. Polymeric ligand-functionalized gold nanorods (Au NRs) are adsorbed onto superhydrophobic surface-modified polydimethylsiloxane (PDMS) microneedles through the control of various interfacial interactions. We show that the chain length of the polymer ligands dictates the NR adsorption process. Importantly, assembling Au NRs onto the micrometer-diameter needle tips allows the formation of highly concentrated electromagnetic hot spots, which provide the SERS enhancement factor as high as 1.0 × 106. The micrometer-sized area of the microneedle top and high electromagnetic field enhancement of our system can be loosely compared with tip-enhanced Raman spectroscopy, where the apex of a plasmonic NP-functionalized sharp probe produces high-intensity plasmonic hot spots. Utilizing our NR-decorated microneedle substrates, the synthetic drugs fentanyl and alprazolam are analyzed with a subpicomolar limit of detection. Further analysis of drug-molecule interactions on the NR surface utilizing the Langmuir adsorption model suggests that the higher polarizability of fentanyl allows for a stronger interaction with hydrophilic polymer layers on the NR surface. We further demonstrate the translational aspect of the microneedle substrate for both SERS- and ssESI-MS-based detection of these two potent drugs in 10 drug-of-abuse (DOA) patient plasma samples with minimal preanalysis sample preparation steps. Chemometric analysis for the SERS-based detection shows a very good classification between fentanyl, alprazolam, or a mixture thereof in our selected 10 samples. Most importantly, ssESI-MS analysis also successfully identifies fentanyl or alprazolam in these same 10 DOA plasma samples. We believe that our multimodal detection approach presented herein is a highly versatile detection technology that can be applicable to the detection of any analyte type without performing any complicated sample preparation.

CO2 capture performance of ceramic membrane with superhydrophobic modification based on deposited SiO2 particles

Membrane absorption is a promising CO2 capture technology, which is limited by the high cost of membrane materials. Coal fly ash (CFA)-based ceramic membrane as an alternative material for membrane modules can effectively reduce the preparation cost. In this study, CFA-based ceramic membrane with superhydrophobic properties is prepared by depositing SiO2 nanoparticles and grafting 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (POTS). Characters including pore size distribution, porosity and N2 flux of superhydrophobic membrane are performed. The superhydrophobic modified ceramic membrane is applied to CO2 capture experiments using ethanolamine (MEA) solution as the absorbent. The result shows that the contact angle of the modified ceramic membrane reaches 155.0°, which significantly improves the anti-wetting properties of the membrane surface. The CO2 capture experiment demonstrates a maximum capture efficiency of 97.45% and a mass transfer rate of 21.17 mol/(m2·h). In addition, the superhydrophobic modified ceramic membrane exhibits excellent thermal and chemical stability, sustaining high performance even after 8 h of continuous operation. This study provides the theoretical and empirical foundation for the application of CFA-based superhydrophobic ceramic membranes in CO2 capture.

Superhydrophobic Nanoparticles: An Efficiently Selective Adsorbent for Surfactant-Like Contaminants from Complex Wastewater Matrices.

Surfactant-like contaminants (SLCs) with distinctive amphiphilic structures have become a global concern in wastewater due to their toxicity and persistency. Despite extensive efforts, achieving efficient and selective SLCs removal remains challenging because of their wide range of molecular weights and complex functional group compositions. Superhydrophobic nanoparticles can potentially tackle this challenge by targeting the long oleophilic chains of SLCs. However, conventional contact angle measurements hinder hydrophobicity characterization and corresponding selectivity research because of the powder morphology of nanoparticles. Herein, the authors offered information regarding the distribution of water molecular probes in surfaces and proposed a quantitative characterization approach based on low-field nuclear magnetic resonance. Through synthesizing superhydrophobic and hydrophilic polydopamine nanospheres with similar morphologies, the selective adsorption potential of superhydrophobic nanoparticles for SLCs is systematically demonstrated. As revealed by the interaction mechanisms, the superhydrophobic surface of nanospheres increased its affinity and selectivity for SLCs adsorption by enhancing hydrophobic interactions. Superhydrophobic modification achieved ten times the adsorption capacity of sodium dodecyl benzene sulfonate, an exemplified surfactant, compared with pristine nanoparticles. By regulated self-polymerization, the superhydrophobic nanospheres are coated onto the surface of a 3D sponge and enable efficient selective SLCs adsorption from highly polluted leachate matrices with long-term stability and reusability.

Ultrastrong lightweight nanocellulose-based composite aerogels with robust superhydrophobicity and durable thermal insulation under extremely environment

Ultra-lightweight porous aerogels based on nanocellulose (NC) have promising applications in various fields such as building insulation, sewage treatment, energy storage, and aerospace. One of the key advantages of these aerogels is their exceptionally low thermal conductivity. Nevertheless, the thermal insulation of NC aerogel (NCA) can deteriorate with changes in temperature and humidity conditions, making it crucial to develop a bulk aerogel that can maintain exceptional thermal insulating properties in harsh environmental conditions. A sustainable and user-friendly approach to synthesizing cellulose/poly(vinyl alcohol) aerogel (CellPA) materials has been developed, which are lightweight, possess good insulating properties, and demonstrate robust superhydrophobicity even in harsh environmental conditions. The CellPA are both exceptionally lightweight and robust, boasting outstanding resistance to combustion while also displaying a thermal conductivity of 36.1 mW m−1 K−1, suggesting they hold great promise for insulation applications. Furthermore, CellPA also exhibits robust superhydrophobicity even under harsh conditions, confirming the homogenous superhydrophobic modification of the biodegradable PVA through chemical methods. The manufacturing of bio-based composite materials with enhanced mechanical and thermal insulation features has gained immense popularity in a broad spectrum of contemporary engineering applications. These composite materials are particularly valuable as a robust, energy-efficient, lightweight, waterproof and flameproof for construction materials.

Improvement of decorative texture effects, thermal stability, and mechanical properties of Pinus massoniana using a combined dyeing and superhydrophobic modification method

Improvement of decorative texture effects, thermal stability, and mechanical properties of Pinus massoniana using a combined dyeing and superhydrophobic modification method

Construction of superhydrophobic film on the titanium alloy welded joint and its corrosion resistance study

PurposeThis study aims to improve the corrosion resistance of TA2-welded joints by superhydrophobic surface modification using micro-arc oxidation technology and low surface energy substance modification.Design/methodology/approachThe microstructure and chemical state of the superhydrophobic film layer were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy, three-dimensional morphology, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared absorption spectroscopy. The influence of the superhydrophobic film layer on the corrosion resistance of TA2-welded joints was investigated using classical electrochemical testing methods.FindingsThe characterization results showed that the super hydrophobic TiO2 ceramic membrane was successfully constructed on the surface of the TA2-welded joint, and the construction of the super hydrophobic film greatly improved the corrosion resistance of the TA2-welded joint.Originality/valueThe superhydrophobic TiO2 ceramic membrane has excellent corrosion resistance. The micro nanostructure in the superhydrophobic film can intercept air to form an air layer to prevent the corrosion medium from contacting the surface, thus, improving the corrosion resistance of the sample.

Investigation on the performance coupling characteristics between a compound anti-frosting method and air source heat pump system

Air source heat pump systems are prone to frosting when operating under low temperature and high humidity working conditions, leading to reduced operational stability and performance. The traditional defrosting methods suffer from defects including high energy consumption, heating interruption, and system pressure surges. To address these issues, a novel active–passive compound anti-frosting method for air source heat pump systems is introduced in this work, which involves utilizing the synergistic effect of high-speed airflow and superhydrophobic modification. To reveal the coupling characteristics between the energy consumption of the anti-frosting method and the system performance, the airflow parameter model based on droplet growth and force taken is established, the simulation algorithm for system frosting and defrosting is developed, and the system's operating characteristics and performance under different operation modes are compared within typical frosting condition. The results indicate that the active–passive compound method can realize frost-free operation and reduce the ant-frosting and defrosting energy consumption by more than 90%. Consequently, it improves the system's comprehensive performance coefficient in a single frosting-defrosting period by 9.7%∼14.3%, compared to the control group without any anti-frosting measures. The introduction of the active method further enhances the frost suppression effect of the superhydrophobic modification.

Superhydrophobic Surface Modification for Enhanced Fabric Face Masks: The Impact of Varying HDTMS Concentrations

The widespread use of disposable surgical masks and N95 respirators has led to concerning environmental pollutions. As a result, there has been a growing demand for fabric face masks that are not only reusable and environmentally friendly, but also effective in preventing virus transmission. However, traditional fabric masks have a drawback: their hydrophilic nature increases the risk of virus transmission. To address this challenge, an innovative solution for achieving superhydrophobic surface on cotton, microfiber, and microfiber blend materials was investigated. The key focus of this investigation revolvesaround the impact of varying concentration of hexadecyltrimethoxysilane (HDTMS) on the hydrophobicity of different fabrics. Consequently, all cotton fabric samples treated with 5%, 10% and 20% HDTMS concentration exhibit water contact angles (WCA) surpassing 150o, effortlessly achieving a state of superhydrophobicity. The modified cotton and microfiber materials proudly display not only enhanced water repellency but also boast exceptional self-cleaning and stain resistant properties.

Synergetic strategy to fabricate superhydrophobic wood by MTMS for improving dimensional stability, durability and self-cleaning ability

A novel two-step synergetic strategy is proposed, i.e., using an eco-friendly methyltrimethoxysilane (MTMS) to prepare superhydrophobic wood by immersion-spraying method. The wood samples were first immersed in MTMS solution followed by spraying with pre-condensed MTMS-based oligomeric species. The as-prepared superhydrophobic wood was proved to have excellent water resistance, dimensional stability, surface durability and self-cleaning peculiarity. The developed strategy offers a new reference for superhydrophobic modification of 3D-porous materials.

Fabrication of asymmetric wettability silk fabrics with plasma-induced grafting polymerization of octamethylcyclotetrasiloxane

Most superhydrophobic surfaces contain fluorine, which is very harmful to the environment. So, it is necessary to change the situation. This paper explains that a simple and fluorine-free plasma technology for superhydrophobic modification of silk fabrics by using one-sided protection method and low-temperature plasma induced grafting polymerization of octamethyl-cyclotetrasiloxane (D4) to form the superhydrophobic films. Treated silk and pristine silk fabrics were measured using field emission scanning electron microscopy(FESEM), Fourier-transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), and water contact angle measurement. The test results showed that the polymer films could be successful coated on the silk fibers surface via the low-temperature plasma. In addition, it has good durability, thermal stability, and a water contact angle of 152°.

Construction and Performance of Superhydrophobic Surfaces for Rusted Iron Artifacts

Ancient iron artifacts need to be protected with a rust layer, often stabilized by tannic acid corrosion inhibition. In humid environments, water vapor could slowly penetrate and trigger galvanic corrosion of metal artefacts. Sealing treatments are generally applied to the artefact surface to isolate water and enhance its corrosion resistance. Superhydrophobic modifications could effectively block the penetration of moisture into the interior of the artefact and provide a nice water barrier. Stearic acid with tannic acid inhibition treatment creates a superhydrophobic protective layer on the surface of rusted iron artifacts and enhances corrosion resistance effectively. Various scientific analyses and testing methods are used in this paper to evaluate the corrosion resistance of rusted surfaces after superhydrophobic modification and investigate the reaction mechanisms. The results indicate that the contact angle of the rusted surface after corrosion inhibition by tannic acid and modified by stearic acid is increased to 152.2°, which means the superhydrophobic protective layer has been successfully constructed. The C/Fe ratio of the rusted surface is increased from 0.21 to 2.10, and the characteristic diffraction peaks of O1s and Fe 2p3/2 shift toward higher binding energy. Stearic acid is combined with the corrosion product layer by chemical bonding. Chelation between rust products, tannic acid, and steric acid is effective, and the chelate is chemically stable. The superhydrophobic surface forms a lamellar wax-like layer as an air barrier to isolate liquid water, resulting in a significant decrease in corrosion current and an increase in Warburg impedance to 217.9 times the original state, with a protection efficiency of 88.3%. Tannic acid corrosion inhibition and stearic acid superhydrophobic modification have an excellent synergistic protective effect on improving the corrosion resistance of iron artifacts, resulting in better corrosion resistance of iron artifact materials. The research provides new ideas and references for the protection of ancient iron artifacts sealing.

Preparation of TiO2 Nanotube Arrays with Controllable Morphology and their Superhydrophobic Modification for Photocatalytic Degradation of Water Pollution

TiO2, as a photoactive semiconductor material, where like photocatalysis technology is a hot topic of research in recent years, shows great potential for application in the direction of environmental pollution treatment and solar-chemical energy conversion. In this paper, we prepared titanium dioxide nanotube arrays (TNAs) by a simple one-step anodic oxidation method in an ethylene glycol electrolyte containing ammonium fluoride under optimized conditions. The effects of anodic oxidation voltage, anodic oxidation time and annealing temperature on the growth of TNAs were systematically investigated. It was shown that the sample parameters of TNAs prepared by anodic oxidation were influenced by the anodic oxidation conditions, and the tube diameter and anodic oxidation voltage were positively correlated in a certain range. The TNAs with the best characterization performance were selected for photocatalytic degradation, and methylene blue (MB) was used to simulate the organic pollutants. The results show that TNAs have better photocatalytic activity compared with conventional TiO2. On the basis of this, stearic acid (SA) and TNAs were compounded and modified. The TNAs were made to obtain superhydrophobic properties. The photocatalytic degradation experiments were carried out on them. The results show that the superhydrophobic modification does not affect their photocatalytic activity, so it is possible to achieve photocatalytic degradation of water pollution under the premise of superhydrophobicity, which has greater application prospects in water pollution treatment.

New developed for generating superhydrophobic surface modification on mild steel for corrosion protection

The synergism effect of sodium tartrate and Zn2+ binary inhibitor system on the corrosion inhibition efficiency of mild steel in an potable water medium containing was analyzed by means of gravimetric and electrochemical spectroscopic measurements. The effect of weight loss method and immersion time on the corrosion behavior of mild steel has also been studied. The scanning electron microscopic (SEM) images showed that the roughness and the deep cracks of the metal surface are reduced significantly by the inhibitor system. Results indicated that the formulation acted as anodic inhibitor. Adsorption of used inhibitor lead to a decrease in the double layer capacitance and an increase in the charge transfer resistance and confirm protective layer by SEM, EDX, AFM and FT-IR. Simple and novel binary inhibitors approach was developed for generating superhydrophobic surface modification of mild steel. Interestingly, Water droplets falling on the leaves bead up and roll off, mild steel immersed in potable water in the presence of binary inhibitor system (sodium tartrate and Zn2+) was attempted to create superhydrophobic surfaces. However, the water contact angle in presence of binary inhibitor system was found to be 152°±4°, whereas in the case of mild steel, it was 55°±2°. A detailed description of the surface-modified superhydrophobic in potable water on mild steel is presented in this article.

Controlled-release fertilizers with an ultralow coating content

The controlled-release fertilizers with superior controlled-release performance and an extremely low coating content were fabricated using castor oil-based polyurethane coatings, followed by dual superhydrophobic modification.

Carbon dot-based superhydrophobic modification of a covalent organic framework for oil-in-water emulsion separation.

A super hydrophobic composite is developed for the first time through the non-covalent self-assembly of a hydrophilic covalent organic framework (COF) and amphoteric CDs to achieve highly selective separation of dispersed micro droplets of oil from an oil/water mixture.