Hydrophobic Films Research Articles

Elucidating the interaction between polar alkoxysilane-modified silicate glass and ionic surfactant in the obtainment of hydrophobic transparent film

Soda-lime-silicate glass is a widely used material in industry and everyday life. For some applications, it is important to have hydrophobic properties of its surface and at the same time retain the transparency in the visible spectrum. This can be achieved using fluoroalkyl silanes as surface modifiers. However, fluorine shows severe health effects and the nowadays tendency is to use more appropriate substances for surface modification. In this work, we show the possibility of obtaining a hydrophobic and transparent film on silicate glass using alkoxysilanes with alkyl groups possessing terminal -NH2 and subsequent modification of such silanized glass using an anionic surfactant. The possible mechanism of the interaction between the chemisorbed silyl group and the dodecyl sulfate ion was discussed.

Corrosion and tribocorrosion resistance of superhydrophobic LPBF-NiTi alloys surface fabricated by nanosecond laser and ultrasonic fluorination

NiTi alloys have been extensively studied for their excellent super-elasticity (SE) and shape memory effects (SME). With the development of laser powder bed fusion (LPBF), it is possible to process the complex structure of NiTi alloy, which results in the mechanical properties of LPBF-NiTi alloys receiving great attention. However, the processing method is different from the traditional one, which not only has an impact on the mechanical properties but also seriously affects the anti-corrosion resistance and causes a substantial deterioration. In the research work of this paper, nanosecond laser processing was used to fabricate the bionic mastoid-shaped micro-nano structure on the LPBF-NiTi alloys. An efficient and convenient ultrasonic fluorination treatment was used to achieve the full surface coverage of FAS-17 in 10 min, and the superhydrophobic LPBF-NiTi alloy surface (CA ~ 157°) was successfully achieved. The constructed superhydrophobic LPBF-NiTi alloy surface exhibits excellent anti-corrosion resistance compared with the original surface, and the icorr from (4.42 ± 0.5) × 10−7 A·cm−2 reduced to (3.21 ± 0.5) × 10−9 A·cm−2. Meanwhile, the superhydrophobic surface showed outstanding stability in the 15-day immersion test n 3.5 wt% NaCl solution. And it is also stable after the tribocorrosion tests in 3.5 wt% NaCl solution at 1 N and 5 N pressures. The remarkable anti-corrosion resistance and stability of the superhydrophobic surface can be attributed to the micro-nano structure rich in the TiO2 oxide layer, the air layer formed by the superhydrophobic surface insulates the corrosive liquid and the stable hydrophobic agent film.

Air-stable silicon hybrid solar cells constructed via hydrophobic polymer film

Air-stable silicon hybrid solar cells constructed via hydrophobic polymer film

A double-layer film based on the strategy of tannic acid-anthocyanin co-pigmentation and tannic-crosslinked-gelatin/−reduced Ag nanoparticles for beef preservation and monitoring

A double-layer film was developed with tannic acid (TA) co-pigmented purple potato anthocyanin extract (PAE)-agar as the inner layer, and K-carrageenan-oregano essential oil Pickering emulsion (OPE)/silver nanoparticles (TA-AgNPs) as the outer layer. Molecular docking and FT-IR results elucidated that intermolecular hydrogen bond was the main interaction between components in the agar-carrageenan matrix, with TA and PAE contributing to intensified anthocyanin color through π-π stacking. The incorporation of OPE/TA-AgNPs enhanced the film's hydrophobicity (WCA > 100°) and UV–vis barrier (close to 0% at 200-320 nm, effectively impeding UVA, UVB, and UVC) properties and exhibited outstanding antioxidant (DPPH scavenging rate > 88%) and antimicrobial activities. This film showed a significant color change in the pH range of 2–12 (from pink to yellow) and a considerable sensitivity to volatile amines within 2 min. The films effectively alleviated beef spoilage (extending the shelf life of beef for 1d) and reflected the freshness of beef during storage. Additionally, the digital color information of the film was obtained by a smartphone combined with RGB values analysis to quantify the freshness of beef rapidly. Therefore, this study expands the application of food packaging films with freshness preservation and monitoring in the field of animal-derived food.

On-site sensing for aflatoxicosis poisoning via ultraviolet excitable aptasensor based on fluorinated ethylene propylene strip: a promising forensic tool

The environmental contamination by extremophile Aspergillus species, i.e., Aflatoxin B1, is hardly controllable in Southeast Asia and Sub-Saharan Africa, which lack handling resources and controlled storage facilities. Acute aflatoxicosis poisoning from aflatoxin-prone dietary staples could cause acute hepatic necrosis, acute liver failure, and death. Here, as the cheaper, more straightforward, and facile on-site diagnostic kit is needed, we report an ultraviolet-excitable optical aptasensor based on a fluorinated ethylene propylene film strip. Molecular dynamics on the aptamer.AFB1 complex revealed that the AFB1 to the aptamer increases the overall structural stability, suggesting that the aptamer design is suitable for the intended application. Under various influencing factors, the proposed label-free strategy offers a fast 20-min on-site fabrication simplicity and 19-day shelf-life. The one-pot incubation provides an alternative to catalytic detection and exhibited 4 times reusability. The recovery of crude brown sugar, processed peanuts, and long-grain rice were 102.74 ± 0.41 (n = 3), 86.90 ± 3.38 (n = 3), and 98.50 ± 0.42 (n = 3), comparable to High-Performance Liquid Chromatography-Photodiode Array Detector results. This study is novel owing to the peculiar UV-active spectrum fingerprint and the convenient use of hydrophobic film strips that could promote breakthrough innovations and new frontiers for on-site/forensic detection of environmental pollutants.

High-barrier, flexible, hydrophobic, and biodegradable cellulose-based films prepared by ascorbic acid regeneration and low temperature plasma technologies

Regenerated cellulose (RC) films are considered a sustainable packaging material that can replace non-degradable petroleum-based plastics. However, their susceptibility to water vapor and oxygen can limit their effectiveness in protecting products. This study introduces a novel approach for enhancing RC films to create durable, flexible, hydrophobic, high-barrier, and biodegradable packaging materials. By exploring the impact of ascorbic acid coagulation bath treatment and plasma-enhanced chemical vapor deposition (PECVD) on the properties of RC films, we found that the coagulation bath treatment facilitated the organized reconfiguration of cellulose chains, while PECVD applied a dense SiOx coating on the film surface. The results demonstrated a significant enhancement in water vapor and oxygen barrier properties of the composite film, almost reaching the level of commercial barrier films. Moreover, the composite film displayed exceptional biodegradability, fully degrading in soil within 35 days. Additionally, it showcased impressive mechanical strength, hydrophobic characteristics, and freshness preservation, positioning it as a valuable option for bio-based high-barrier packaging applications.

De-icing behavior and efficiency of electrothermal film surfaces with different non-wettability in low-temperature flow field

The electrothermal anti-/de-icing technology with excellent de-icing efficiency has been widely applied to eliminate the icing threat on airfoil, whose essence is heat transfer process between heating surface and ice. However, the heat transfer behavior and interfacial transformation form of ice accretion are indistinct on traditional non-superhydrophobic surfaces and rapidly-developed superhydrophobic surfaces in the low-temperature flow field. Therefore, the heat transfer and solid-ice interface transform behavior on film heater surface were explored in this work by analyzing the temperature-rising performance and de-icing characteristics of hydrophobic films (HPoF) and superhydrophobic films (SHPoF) in the icing wind tunnel. The results indicated that the faster wind speed enhanced the convection and radiant heat loss of the film heater, and the peak temperature of film heater was directly affected by the environment temperature. Moreover, the SHPoF had lower de-icing consumption than HPoF in an environment without wind field, which was less related to the ice accretion. However, the de-icing form transformed from shearing to shedding mode with the growth of ice accretion under wind field conditions. In the shearing de-icing mode, the lower environment temperature and faster wind speed caused longer de-icing time, whereas the deicing time shortened with the decrease of environment temperature in the shedding mode. When the icing time was 1 min, the de-icing time of SHPoF increased by 12.25%–25.73 % due to the slower heat transfer at the solid-gas-ice interface compared to the solid-liquid-ice interface of HPoF. With the further increase of icing time, the ice accretion was removed after the melt of interfacial ice. The less solid-ice contact points were present at the solid-gas-ice interface on SHPoF surfaces, resulting in energy saving of 20.16%–40.46 % compared to HPoF surfaces. Therefore, the electrothermal superhydrophobic de-icing technology exhibited energy-efficient characteristics when the self-weight of ice is the primary driving force for de-icing process.

Enhancing corrosion inhibition performance of benzyl quinolinium chloride by the use of allicin in lactic acid

The synergistic inhibitive effect of benzyl quinolinium chloride (BQC) with allicin on N80 specimens in 15 % lactic acid environment at 363 K was investigated using weight loss experiments, electrochemical tests, and surface analysis techniques (including scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS), and contact angle measurement), quantum chemical calculation as well as molecular dynamics (MD) simulation instruments. In the presence of allicin, the inhibition performance of BQC was significantly improved. The inhibition efficacy (IE) reached 96.49 % at the optimal mass ratio of 5:1(BQC/allicin) with the total inhibitor mass fraction of 0.1 %. Electrochemical testing demonstrated that the composite inhibitor impeded the corrosion process and the composite corrosion inhibitor was belong to hybrid inhibition type. Surface analysis techniques indicated that the composite corrosion inhibitor formed a hydrophobic adsorptive protective film to avoid the erosion of corrosion factors on the metal surface. The mechanism of the synergistic corrosion inhibition effect was further clarified, in terms of electrostatic attraction, intermolecular interactions and adsorption process through molecular dynamics simulation (MD) as well as density functional theory (DFT). The composite corrosion inhibitor composed of BQC and allicin formed a complete and dense adsorption protective film on the metal surface under the combined effect of physical and chemical adsorptions. The combination of BQC and allicin in proper ratio shows promising application potential as an efficient corrosion inhibitor in lactic acid based acidizing fluids.

Substrate controlled hydrophobicity of the Y2O3 films

The development of hydrophobic surfaces is an important factor for clean energy production from solar arrays, enabling their operation at the highest possible efficiencies for the longest possible time, without the need for physical intervention. This work reports the development of hydrophobic Y2O3 thin films on a range of transparent glass substrates. The growth of the Y2O3 films from the mono-hydrate yttrium (III) complex of 1,3-diphenyl-1,3-propanedione [Y(dbm)3(H2O)] is studied using the aerosol-assisted chemical vapor deposition (AACVD) technique. The qualitative evaluation of the deposited films and their hydrophobicity is assessed using several materials characterization techniques, such as scanning electron microscopy, grazing incident X-ray diffraction, Fourier-transform infrared, X-Ray photoelectron spectroscopy, in addition to a surface free energy and water contact angle measurements. This work demonstrates experimentally a relationship between the Y2O3 wettability and its physico-chemical characteristics in terms of surface energy, chemical composition, and morphology which is controlled by the type of glass support used. The water contact angle of the hydrophobic Y2O3 coating grown on the F-doped tin oxide glass reached 128°; currently the first deposited on transparent glass. This film exhibits the highest WCA reported up to date without the need for performing post-reaction surface treatment processes. The hydrophobic nature of the transparent Y2O3 films marks a significant leap forward in the field of anti-soiling coatings suitable for photovoltaic technology.

Amphiphilic block and random copolymers: aggregation and hydrophobic modification on metal-free tanned collagen fibers

Hydrophobicity enhancement of metal-free leather, which is crucial for improving its comprehensive performance, can be achieved by using amphiphilic copolymer retanning agents. However, the relationship between the sequential structure and the hydrophobic modification effect of amphiphilic copolymers remains unclear. Herein, an amphiphilic block copolymer was synthesized using stearyl methacrylate and 2-(dimethylamino)ethyl methacrylate via atom transfer radical polymerization, and the corresponding random copolymer with similar monomer compositions and molecular weights was prepared for comparison. The aggregation behavior of block and random copolymers was investigated. DLS and TEM results indicate that the block copolymer exhibits a larger aggregate size than the corresponding random copolymer. Molecular dynamics simulations suggest that the block copolymer aggregate exhibit a thicker hydrophilic shell and more concentrated distribution of cationic DMA block than the random copolymer aggregate. Subsequently, the block and random copolymers were used for the hydrophobic modification of metal-free tanned collagen fibers (CFs). The block copolymer shows superior binding capacity to CFs than the random one because of its larger size and more concentrated charge distribution. Hence, the block copolymer can form a dense and uniform hydrophobic film on the surface of collagen fibrils and endow CFs with higher hydrophobicity than the random one. This work provides theoretical guidance for modulating the hydrophobicity of CFs by tailoring the sequential structure of amphiphilic copolymers, which is expected to inspire the manufacturing of high-performance metal-free leather.Graphical

Experimental, theoretical and computational studies of oxalyl dihydrazide as a novel corrosion inhibitor for mild steel in neutral saline solution

In this work, the corrosion inhibition performance and mechanism of oxalyl dihydrazide (ODH) for mild steel in neutral saline solution are in-depth studied using weight-loss and electrochemical tests, surface characterizations, theoretical calculation and computational simulations. Results indicate that ODH can act as a novel and superior mixed-type corrosion inhibitor for mild steel in neutral saline solution, its corrosion inhibition efficiency increases with the rising ODH concentration, and the optimum value reaches 88.7 % with adding 200 mg/L. Its corrosion inhibition ability becomes better with immersion time. A compact corrosion product film mainly consisting of Fe, O, N and Cl elements formed on metal surface after adding ODH. ODH molecules adsorb on metal surface in an orderly fashion to form a hydrophobic film, which is belonging to the physicochemical adsorption and obeys the Langmuir adsorption isotherm model. The corrosion inhibition process of ODH molecule on mild steel is the endothermic process, which enlarges the activation energy barrier of corrosion reactions. ODH molecule can expel the adsorbed water molecules on metal surface and form copolymers with increasing of ODH concentration, retarding the diffusion of water molecule thus protecting metal from corrosion. ODH is proved to be an effective organic corrosion inhibitor for protecting mild steel in neutral saline solution, and contributes toward research and application of easily accessible sources for organic corrosion inhibitors.

Enhanced corrosion resistance performance of the novel tripodal imidazolium-based ionic liquid: Experimental and theoretical investigations

The imidazolium-based ionic liquids (ILs) were widely recognized as the eco-friendly corrosion inhibitors. Many literatures focused on enhancing the corrosion inhibition efficacy via the modification of various functional groups to ILs. The present study investigated the corrosion resistance performance of the novel synthesized tripodal IL ([(C4im)3TA][Cl3]) with a triazine spacer and three imidazolium cations for mild steel (MS) in 1 M HCl solution. The inhibition efficiencies of [(C4im)3TA][Cl3] at the concentrations of 0.1 mM (55.7 ppm, 80 %) and 0.5 mM (278.5 ppm, 86 %) were found to be comparable to, and higher than that of conventional imidazolium-based ILs 1‑butyl‑3-methylimidazolium chloride (C4mimCl) at 10 mM (1747 ppm, 81 %), respectively. The adsorption behavior of [(C4im)3TA][Cl3] at the metal surface was reflected through X-ray photoelectron spectroscopy, and the adsorption mechanism was further investigated using quantum chemical calculations and molecular dynamics simulations. The results indicated the greater ability of [(C4im)3TA][Cl3] to form chemical bonds with Fe atoms, which induced the generation of the more stable hydrophobic protection film at the surface. This study presented the novel concept for the structural design of high-efficiency corrosion inhibitors based on imidazolium ILs.

Small Organic Molecules with Anchoring Adsorption Enhance Corrosion Inhibition of Zinc Electrodes in ZnSO4 Medium

AbstractIn this study, trimercapto‐S‐triazine trisodium salt (TMT) with threefold rotational symmetry as a corrosion inhibitor was introduced into 2 mol ⋅ L−1 ZnSO4 medium. By electrochemical measurements, the corrosion inhibition efficiency of the zinc electrodes was 92.52 % when the concentration of TMT corrosion inhibitor was 2 mmol ⋅ L−1. Based on the microstructural characterization and theoretical analysis of Zn electrodes, it was confirmed that S and N atoms of TMT corrosion inhibitor serve as alternately zinc‐philic adsorption sites with sixfold rotational symmetry for the formation of intermolecular complexes. Adsorption energies of TMT on Zn surfaces were calculated and indicated that the bonds of Zn−N and Zn−S promoted anchoring adsorption on sixfold symmetric (002) plane of zinc. Meanwhile, TMT corrosion inhibitor can adsorb Zn2+ from the electrolyte and directionally deposit them on the surface of Zn (002), effectively avoiding the occurrence of dendrites. This study changes the common knowledge that organic corrosion inhibitors must form hydrophobic films to have corrosion inhibition performance, and provides a new approach for using small organic molecules with anchoring adsorption as metal corrosion inhibitors.

Fabrication of Porous Zn Alloy Scaffolds Coated with Hydrophobic Film and Their In Vitro Biodegradation Properties

Fabrication of Porous Zn Alloy Scaffolds Coated with Hydrophobic Film and Their In Vitro Biodegradation Properties

Facile design of PTFE-kaolin-based ternary nanocomposite as a hydrophobic and high corrosion-barrier coating

Abstract Superhydrophobic nanostructured coatings are a promising technology in construction engineering. This study developed a hydrophobic film through a simple mixing method, utilizing kaolin and polytetrafluoroethylene as additive particles, 1H,1H,2H,2H-perfluoro-decyl triethoxysilane as a modifier, and epoxide resin and polyamide curing agent as adhesives. By controlling variables, it was determined that the C1P0.2EP coating immersed in a 3.5 wt% NaCl solution for 1, 3, and 7 days exhibited the maximum impedance radii of 47,373, 20,334, and 1,982 Ω·cm2, respectively. It also demonstrated the highest Bode modulus values, the largest E corr, and the smallest I corr. Furthermore, after 300 h in a salt spray chamber with a 3.5 wt% NaCl solution, the C1P0.2EP coating showed no rust spots or bubbles, demonstrating its excellent corrosion resistance. Moreover, wear resistance tests and self-cleaning experiments were conducted on the C1P0.2EP coating. The results showed that after 100 friction cycles, the surface exhibited no visible scratches, and the contact angle of the coating decreased by only 4°. Additionally, neither soil particles nor dirty water adhered to the coating, indicating that the C1P0.2EP hydrophobic coating possesses not only excellent corrosion resistance but also superior wear resistance and self-cleaning capabilities.

Multifunctional PPy/MXene decorated polylactic acid film for thermal management and electromagnetic interference shielding

Composite films composed of biodegradable materials possessing flexibility, thermal regulation capabilities, and electromagnetic interference shielding attributes represent optimal selections for wearable items and the packaging of devices. Here, we employ a simple alternating immersion and spray-coating process to fabricate flexible multifunctional films by combining hydrophobic PLA electrospun film with PPy and MXene, and investigate the thermal management and electromagnetic interference shielding properties of the films. Through alternating immersion, PPy can be rapidly in-situ polymerized on the PLA film, enhancing the surface roughness of the fibers, enabling firm integration of MXene with the film. Benefiting from the broad wavelength absorption characteristics of PPy, the solar absorption capacity of the film is significantly enhanced (97.16 %), endowing it with excellent photothermal conversion capability. Meanwhile, the high conductivity of MXene imparts the composite film with controllable and stable active heating ability, meeting heating demands under complex weather conditions. Finally, inspired by origami techniques the electromagnetic interference shielding performance of films with different folding frequencies was compared. It was found that attributed to the increased reflection paths, the film exhibited a significant improvement in electromagnetic interference shielding performance (32.58 dB to 51.96 dB) after folding. In brief, this biodegradable multifunctional composite film is an attractive candidate for future wearable products or devices packaging.

Anti-blue light and hydrophobic composite film based on iron oxide and FAS-modified SiO2

With the increasing application of display and lighting devices, the potential injury to human eyes due to blue light has been attracting significant attention. While current anti-blue light films are complex, costly and low stability in humid environments. In this work, anti-blue light films were fabricated using iron oxide as blue light absorbent and polyvinylpyrrolidone as surfactant, under various Fe3+ concentrations and annealing temperatures. Particularly, the films annealed at 300 °C exhibited 60 % absorption rate of blue light in 400–450 nm wavelength range on average and still maintained 96 % transmittance to 500–800 nm visible light. Moreover, the films coated with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS)-modified SiO2 hydrophobic layer showed high hydrophobicity and sequential humid-heat stability. Meanwhile, no obvious changes occurred in transmittance spectra after keeping at 85 °C and 85 % relative humidity for 15 days. With the composite film covered, the color rendering index of the display screen decreased only 0.7 %, while the blue light weighted radiance decreased significantly by 37.1 %. Furthermore, cell experiments with composite films demonstrated that human retinal pigment epithelium cells were effectively protected from blue light injury. Overall, the composite films with high stability exhibited desired anti-blue light function.

81‐3: One‐to‐One Microlens Array with Pixel for Full‐Color Organic Light‐Emitting Diode Display

In this study, we successfully accomplished a one‐to‐one micro‐lens array with pixel via printing technology on a hydrophobic film layer without pattern. By meticulous adjustments to the lens printing process and device structure, we achieved a notable increase in current efficiency exceeding 30% for RGB OELD.

Attempts to Obtain Material Based on Polyvinyl Alcohol with Barrier Properties against Water Vapor

The purpose of this study was to obtain a biodegradable film based on polyvinyl alcohol with reduced water vapor permeability. The hydrophobic character of the films was achieved by incorporating beeswax, vegetable bio-surfactant, citric acid as a cross-linking agent, and glycerol to provide elasticity, along with the application of thermal treatment. Water vapor permeability was determined gravimetrically. The results indicated that all films produced had lower water vapor permeability compared to unmodified or untreated polyvinyl alcohol films. The barrier to water vapor varied directly with the mass of beeswax used, and the homogeneous dispersion of beeswax in the polyvinyl alcohol matrix was essential for achieving an efficient hydrophobic film. The best performing-material exhibited a water vapor permeability 5.15 times lower than that of the neat polyvinyl alcohol and 15 times higher than that of polyethylene. Considering the fact that the water vapor barrier property of neat polyvinyl alcohol was 78 times lower than that of polyethylene, the combination of beeswax, citric acid, and vegetable bio-surfactant—along with thermal treatment—can be a viable solution to reduce the hygroscopicity of polyvinyl alcohol-based films.

Hydrophobic polyethylene film prepared by film blowing process for preservation of fried shrimp rolls

Hydrophobic coatings have wide applications, but face challenges in food flexible packaging in terms of poor adhesion and inadequate wear resistance. Health hazards and poor adhesion drive the search for novel hydrophobic coatings substitutes. Here, we introduced rationally synthesized carnauba wax-SiO2 microspheres as a component to composite polyethylene (PE) film construction, and created a wear-resistant hydrophobic composite PE film via the blown film technique. The resultant hydrophobic composite film demonstrated an enhanced water contact angle from 86° to above 100°, coupled with favorable mechanical properties such as wear resistance, tensile strength and effective barrier performance against water vapor and oxygen. Upon implementation in the preservation of a Cantonese delicacy, Chaoshan fried shrimp rolls, it was observed that at 25 °C, the carnauba wax-SiO2-PE composite packaging film extended the shelf life of the product by 3 days compared to pure PE film.