Contact Angle Measurement Techniques Research Articles

Fabrication of Superhydrophobic Coating (SiO<sub>2</sub>/PDMS) by a Simple Method

A simple and economical method for producing a superhydrophobic surface on a glass substrate is investigated. The surface composes of silica particles synthesized via a sol-gel method with an average particle size of 69.33 nm. Organosilan PDMS (FS-1200 silicon sealant) was used to reduce the surface energy of particles, which were then coated onto a glass substrate by dip coating. After coating, the substrate was dried for one hour at 60ºC in an oven to remove excess solvent. XRD, FE-SEM, FTIR, and contact angle (CA) measurement techniques were used to characterize silica particles and coated surfaces. The water contact angle (WCA) of pure SiO2 (NPs) was 86º indicating its hydrophilic qualities, while the contact angle of a superhydrophobic surface was 156º.

Effects of surface functional groups on the wettability of biodiesel combustion particulate matter

This paper investigates the impact of particle surface functional groups on the wettability of particulate matter (PM) emitted from biodiesel engines. Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectrometry (XPS), and Contact Angle Measurement techniques were employed to detect and analyze PM generated from combustion of diesel, soybean oil methyl ester (SME), palm oil methyl ester (PME), and waste edible oil methyl ester (WME) biodiesels. The results showed that PM derived from biodiesel exhibited a higher content of aromatic nuclei compared to that from diesel. The surface of the PM displayed significantly elevated levels of C–OH functional groups in comparison to CO functional groups, and the relative proportion of C–OH and CO functional groups on the biodiesel-derived PM surface decreased with an increase in biodiesel iodine value. The contact angles of the PM to the diesel droplets were less than 20°, and the PM is highly lipophilic. The wettability of the PM with both water and diesel droplets increased as the relative content of C–OH and CO functional groups rose. Moreover, it was observed that biodiesel-derived PM exhibited superior wettability towards water and diesel droplets when compared to its diesel counterpart, thereby enhancing its susceptibility to wetting by diesel droplets.

Experimental investigations on polydopamine coated poly lactic acid based biomaterial fabricated using 3D printing for orthopedic applications

Polymer based implants provide excellent biocompatibility due to porous structure and minimum chances of stress shielding. However, 3D Printed PLA structures possess insufficient mechanical strength, restricting their utility in biomedical domain. This challenge can be addressed by enhancing their mechanical properties through surface modification. The one-step oxidative polymerization process transforms dopamine hydrochloride into biocompatible polydopamine coating, that facilitates adhesion to both hydrophilic and hydrophobic surfaces. The mechanical performance of these structures is influenced significantly by the printing and coating parameters. Thus, this study undertakes the fabrication of bone plates at varying printing parameters followed by investigating the effects of polydopamine coating on their tensile and flexural behavior across varying coating conditions. In the study, SEM/EDS analysis has been performed for examining the morphological characteristics, interaction of coating with PLA and assessing the elemental distribution on the coated surface. The study further explores the impact of coating on substrate roughness and hydrophilicity through AFM and water contact angle measurement techniques. The deposition of polydopamine coating on PLA bone plates was confirmed using XRD and Raman spectroscopy. Upon application of coating, the findings suggested enhancement in tensile strength and flexural strength in the ranges of 47.18%–94.47% and 8.5%–33.78% respectively, across varying printing parameters. Similarly, varying coating parameters resulted in improvement ranging from 38.68% to 93.03% for tensile strength and 2.8%–30.57% for flexural strength. Furthermore, the deposition of coating substantially enhanced the hydrophilicity of the bone plates, making them suitable for tissue engineering applications. Thus, the successful deposition of polydopamine coating not only enhanced the mechanical behavior but also improved the hydrophilicity of bone plates, thereby advancing their suitability for biomedical applications.

Theoretical and experimental approaches to the preparation, characterization and application of a newly synthesized mesoporous Zn-MOF as a selective ionophore for Ni(II) ion in carbon paste electrode matrix

A novel carbon paste electrode (CPE) chemically modified with a newly synthesized Zn-metal organic framework (Zn-MOF) was synthesized for Ni(II) ion determination with impressing enhancement in sensitivity and selectivity over the preceding studies. Due to their electrocatalytic and substantial surface area criteria, MOFs are a reasonably new category of fascinating materials for precise electrochemical detection. Under the sonication condition, a novel Zn-MOF depending on a Schiff base ligand in nano size was synthesized, and it was characterized using different characterization methods such as powdered X-ray diffraction (PXRD), FT-IR, BET surface area, contact angle and scanning electron microscope (SEM) combined with energy dispersive X-ray analyzer (EDX). The BET surface area and contact angle measurement techniques results were 2901.08 m2 g−1 and 143.49°, respectively, for the synthesized MOF. It was concluded that under the ideal experimental circumstances, the produced Zn-MOF can extract and sense nickel ions from aqueous solution selectively. Several crucial factors were optimized to gain the ultimate electrochemical response. Response mechanism was proved by the aid of study of morphological change and functional groups chemical shifts. Ultimately, a calibration with a Nernstian slope of 28.75 mV decade−1 over linear concentration limits from 5.0 × 10−8 to 1.0 × 10−1 mol L−1 (R2 = 0.9990) and detection limit of 5.0 × 10−8 mol L−1 was obtained. The relative standard deviations and recovery ranges of the proposed approach for determining the Ni(II) ion in various water and food tests (n = 5) were 0.94–2.35% and 97.0–104%, respectively.

Deciphering the role of antisolvent on the structural and optical properties of CH3NH3PbI3 film and its impacts on the performance and stability of n-i-p perovskite solar cells

This study presents an in-depth morphological, structural, and optical study of CH3NH3PbI3 (MAPbI3) film during the antisolvent dripping time, and their relevance to the stability and performance of perovskite solar cells (PSCs) is revealed. The detrimental role of the antisolvent is best demonstrated by using chlorobenzene (CB) as an antisolvent and comparing PSC devices fabricated from CB-free versus PSCs containing CB at different dripping times (5, 10, 15, 20, and 25 s) before the end of deposition of CH3NH3PbI3 film (deposition time was 30 s). Scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis absorption spectroscopy, Urbach energy analysis, steady-state photoluminescence (PL) spectra, current-voltage (I–V), external quantum efficiency (EQE), and water droplet contact angle measurement techniques were utilized to evaluate the characteristics of obtained MAPbI3 films, photovoltaic parameters, and the stability of constructed n-i-p PSCs. It was observed that changing the antisolvent dripping time changes the optical and structural properties of the MAPbI3 layer, including the direct and indirect optical band gap, refractive index, extinction coefficient, dielectric constant, optical conductivity, Urbach energy, dislocation density, lattice strain, crystallite size, and lattice parameters. The above-mentioned parameters were investigated in detail. Accordingly, by dripping the CB at 20 s before the end of the deposition process (labeled as a sample of 20 s), the created MAPbI3 layer had a smoother and pinhole-free surface, resulting in higher crystallinity than the other samples. The values of the direct band gap of the created MAPbI3 films varied from 1.51 to 1.61 eV, corresponding to samples CB-free and 20 s, respectively. For all samples, the indirect band gap was 60 meV lower than the direct band gap. Also, the sample at 20 s had a lower Urbach energy, indicating that this sample's interband defects are less than other models. In addition, the PSCs with CB-dripping at 20 s exhibited higher power conversion efficiency (13.95%) and outstanding stability of power output (<16% decay) as compared to the device without CB-dripping (>82% decay) after keeping in ambient air for about 1450 h at 40 ± 10% RH and 25 ± 5 °C. This systematic comparative study of the structural and optical properties of the perovskite layer can provide a promising platform for achieving high-quality perovskite films to overcome the shortcomings of instability and degradation.

Characterization and investigation of properties of copper nanoparticle coated TiO2 nanotube surfaces on Ti6Al4V alloy

In this work, to investigate surface, corrosion and in vitro biological properties of the CuNPs-coated nanotube surfaces, antibacterial, bioactive and biocompatible nanoparticle-coated nanotube surfaces were produced on Ti6Al4V alloys by combined anodic oxidation (AO) and electrodeposition (ED) techniques for implant applications. All surfaces were characterized by SEM, EDX-mapping and -area, XRD, AFM and contact angle measurement techniques. The electrochemical and biological properties such as antibacterial activities, protein adsorption, ALP activity, hemolytic activity and cell viability of the surfaces were investigated in detail. Electrochemical corrosion resistance of CuNPs-coated nanotube surfaces were enhanced respect to uncoated Ti6Al4V alloy under simulated body fluid (SBF) conditions. Antibacterial properties, cell viability and ALP activity of CuNPs-coated nanotube surfaces were improved with compared to uncoated Ti6Al4V alloys. In addition, protein adsorption and hemolytic activity of CuNPs-coated nanotube surfaces were reduced. This work indicates a potential to precisely fabricate an antibacterial, bioactive and biocompatible CuNPs-coated nanotube surfaces on Ti6Al4V to fulfill orthopedic and dental implant needs by using combined AO and ED processes.

Development of flat absorber black anodic coating on 3D printed Al–10Si–Mg alloy for spacecraft thermal control application

Black anodic coating (BAC) is developed on 3D printed or additively manufactured (AM) Al–10Si–Mg alloy by sulphuric acid based anodization technique at low (∼9 °C) temperature. The microstructural and surface properties of the coating are investigated by optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and water contact angle (WCA) measurement techniques. The solar absorptance and infrared (IR) emittance of the coating have been evaluated in the range 200–2500 nm and 3–30 μm, respectively. Nanoindentation technique is employed with low load to evaluate the hardness and modulus of the coating at microstructural length scale. The anodic coating shows superior hardness (∼3.95 GPa) and modulus (∼96 GPa) as compared to reported literature values, possibly due to dense microstructure and the presence of harder ceramic phases, e.g., alumina and kyanite in anodic coating. Further, due to dense microstructure, corrosion resistance improves significantly after anodization of AM alloy. Finally, thermo-optical properties are not altered after the space environmental tests which ensures the usage of the present anodic coating on AM Al alloy for spacecraft thermal control application. The solar absorptance (0.87) and IR emittance (0.78) obtained for the present coating as flat absorber characteristics are higher than the coatings processed on conventional wrought alloys. The present anodic coating shows substantial improvement in mechanical, thermo-optical and corrosion properties due to higher silicon content unlike conventional wrought alloy and refinement in microstructure during additive manufacturing aiding continuous and uniform anodic oxide layer.

Degradation Performance Investigation of Hydrothermally Stressed Epoxy Micro and Nanocomposites for High Voltage Insulation.

Epoxy resins have demonstrated remarkable properties with potential for usage as high voltage insulators. However, a loss of these properties has been observed in high temperature and humid environments. In order to enhance the hydrothermal stability of epoxy resins, micro (15% SiO2) and nano (5% SiO2) silica-based composites of epoxy were fabricated and subjected to standard long term and short term accelerated hydrothermal conditions. To analyze the effect of these stresses, the samples were analyzed periodically through Fourier transform infrared spectroscopy (FTIR) for structure analysis; scanning electron microscopy (SEM) for surface analysis of long-term aged samples; and optical microscopy for the surface topography of short-term aged samples. The Swedish Transmission Research Institute (STRI) classification and contact angle measurement techniques were used for hydrophobicity analysis of long-term and short-term aged samples, respectively. After aging in both conditions, the nanocomposite showed better results as compared to the other samples. After 1000 h of aging, it showed HC-5 class of hydrophobicity, whereas EMC and NE degraded to the HC-6. In case of short-term aging, the contact angle decreased to the 64.15° and 75.05° from 104.15° and 114.9° for ENC and EMC, respectively. Also, in terms of structural degradation, ENC showed the highest structural stability after 1000 h of aging with the highest stable peak of aromatic ether at 1300–1500 cm−1. Microscopic observation through scanning electron and optical techniques also revealed superior performance of the nanocomposites.

Electrostatic Deposition of Bio-Composite Polymer/Hydroxyapatite Coatings on 316L Stainless Steel

The present work aims to prepare polymer-based biocomposite coated layers by electrostatic spray method onto a 316L stainless steel substrate. Different percentages of ( 2,4, and 8) wt.% of Hydroxyapatite (HA) with (98,96, and92) wt.% of PMMA were used to prepare the composite coating. Wettability, phase composition, and surface morphology were studied using contact angle measurement, X-ray diffraction, and scanning electron microscopy techniques respectively. The results revealed that a homogenous, uniform, and crack-free coating layers were obtained. The wettability testing indicated increased hydrophobicity of the coatings with the addition of hydroxyapatite particles where the 8wt.%HA applied the highest contact angle of (104.08o).The average thickness was about (400µm) for the coating layer deposited on the substrates using the electrostatic technique, whereas the average diameter coating was about (33.95µm).

Synthesis, characterization and supercapacitive application of nanocauliflower-like cobalt tungstate thin films by successive ionic layer adsorption and reaction (SILAR) method

For the first time, cobalt tungstate (CoWO4) thin films were synthesized by successive ionic layer adsorption and reaction (SILAR) method. The monoclinic crystal structure of CoWO4 film was confirmed from X-ray diffraction (XRD) technique. The elemental, surface morphological, structural, and electrical analyses were executed using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), two point probe method, and contact angle measurement techniques. The surface morphology of CoWO4 thin film consisted of islands of agglomerated cauliflower-like spherical nanoparticles with hydrophilic nature. The specific surface area of 60 m2 g−1 with an average pore size of 1.10 nm. The CoWO4 thin film electrode exhibited specific capacitance of 1436.5 F g−1 at a scan rate of 2 mV s−1 in 1 M KOH as well as capacitance retention of 94% over 3000 galvanostatic charge discharge (GCD) cycles. Furthermore, flexible solid-state symmetric supercapacitor (FSS-SSC) device assembled using CoWO4 thin films, showed specific capacitance of 101.32 F g−1, specific energy of 14.07 Wh kg−1 and specific power of 1225.25 W kg−1. This work highlights simplistic preparation of CoWO4 thin films for energy storage application.

Effects of asphaltene structure and polythiophene-coated magnetite nanoparticles on surface topography and wettability alteration of silica surface

Natural chemical structures in asphaltene cause it to form a colloidal aggregate that can affect crude oil properties, alter the wettability of reservoir rock surface, and reduce oil recovery. The objective of this research work is to investigate variations in surface properties of silica surface such as topography and wettability during asphaltene precipitation in the presence of magnetite (Fe3O4) nanoparticles (NPs). The magnetite nanoparticles (MNP) are coated with polythiophene to make them more stable and enhance their adsorption capacity. The structure of three asphaltenes used in this research work is determined using nuclear magnetic resonance (NMR), elemental analysis, and Fourier-transform infrared spectroscopy (FTIR) to obtain more details about asphaltene adsorption on the surface of the polythiophene-coated magnetite nanoparticles (MNP@PT). The results show that heteroatoms (e.g., O, N, and S) and aromatic rings as functional groups can affect asphaltene agglomeration and adsorption process onto silica surface. Atomic force microscopy (AFM) is used to obtain adequate topography information. Roughness parameters show that a heterogeneous surface is formed after asphaltene precipitation on the homogeneous silica surface. Contact angle measurement technique and modified Wenzel model are used to investigate the effect of MNP@PT on wettability alteration. The change in contact angle for pure silica upon asphaltene precipitation is lower in the presence of MNP@PT. The silica surface is extremely oil-wet after asphaltene precipitation, but it becomes preferentially oil-wet in the presence of MNP@PT. We showed that MNP@PT are an excellent absorbent to reduce asphaltene precipitation/deposition. The outcome of this research work can increase the current understanding of molecular interactions between asphaltene and solid surfaces in the presence of MNP@PT to reduce impact of asphaltene precipitation on wetness characteristics of the silica surface during oil production.

Using contact angle measurement technique for determination of the surface free energy of B-SBA-15-x materials

Pure and boron-containing, Santa Barbara Amorphous (SBA-15) mesoporous materials and B-SBA-15-x (x is molar ratio of Si/B = 50, 30, 10), were synthesized via a direct hydrothermal method. Samples were characterized by XRD, BJH pore size distribution and SEM techniques. A contact angle technique was used to determine surface free energy and its dispersive and polar components. For this purpose, ethylene glycol (EG), di-iodomethane (DIM), formamide (FA) and water were used as model liquids to detect the contact angles. The OWRK/Fowkes approach was used to calculate the surface free energy values. Total surface free energy (γS) values of pure SBA-15 and B-SBA-15-50, B-SBA-15-30, B-SBA-15-10 were calculated as 64.365, 63.545, 63.490 and 64.218 mJ/m2 at room temperature, respectively. The main results of the study can be summarized as follows: (i) The contact angle measurement technique is suitable for determining the total surface free energy (γS) and its dispersive and polar components (γSd and γSp, respectively) of SBA-15 mesoporous materials and (ii) Addition of boron did not have a significant impact on the characteristic structure of SBA-15.

Characterisation of the PMMA surface subjected to an electrical discharge

ABSTRACT This experimental work discusses the behaviour of PMMA samples surface aged under electrical discharges at ambient pressure and temperature. Ageing tests were carried out for different time durations ranging from 0 to 8 hours. The degradation of the polymer surface was studied using several characterisation techniques, namely, the contact angle measurement technique, the surface analysis technique and the observation technique. Surface degradation was observed using a scanning electron microscope (SEM) and evaluated by FTIR/ATR spectroscopy. Finally, using three different liquids, water, glycerol and diiodomethane, the measurement of the contact angle allowed us to calculate the adhesion work and the surface energy as well as its polar and non-polar components. The results obtained show that electrical ageing affects greatly the physico-chemical properties of the material studied.

A study on use of Telmisartan drug for corrosion inhibition of zinc in 0.1M hydrochloric acid: Surface characterization and Quantum studies

Corrosion inhibition property of Telmisartan on zinc in 0.1 M HCl medium was investigated by chemical and electrochemical techniques. Inhibition action of Telmisartan was found to be increased with increase in concentration and decreased with raise in temperature. Maximum inhibition efficiency of 77% was observed at 20 ppm inhibitor concentration. Inhibition action of inhibitor is due to adsorption on zinc metal surface and it follows the Langmuir adsorption isotherm. Influence of temperature on inhibition action of Telmisartan was studied through activation parameters. Surface morphology of zinc surface with and without inhibitor was examined through SEM and EDX. Surface roughness was studied by AFM and contact angle measurement techniques. FTIR spectral studies confirmed the protecting nature of Telmisartan on zinc corrosion. Quantum chemical data were calculated to prove its suitability as a corrosion inhibitor and to describe the effective adsorption of Telmisartan molecule.

Analysis of Mechanical and Wettability Properties of Natural Fiber-Reinforced Epoxy Hybrid Composites

Natural fibers have many advantages over synthetic fibers due to their lightness, low cost, biodegradability, and abundance in nature. The demand for natural fiber hybrid composites in various applications has increased recently, because of its promising mechanical properties. In this research work, the mechanical and wettability properties of reinforced natural fiber epoxy resin hybrid composites were investigated. The main aim of this research work is the fabrication of hybrid composites and exploit its importance over individual fiber composites. The composites were fabricated based on the rule of hybridization mixture (0.4 wf) of two fibers using sets of either hemp and flax or banana and pineapple, each set with 40 wt%, as well as four single fiber composites, 40 wt% each, as reinforcement and epoxy resin as matrix material. A total of two sets (hemp/flax and banana/pineapple) of hybrid composites were fabricated by using a hand layup technique. One set as 40H/0F, 25H/15F, 20H/20F, 15H/25F, 0H/40F, and the second one as 40B/0P, 25B/15P, 20B/20P, 15B/25P, 0B/40P weight fraction ratios. The fabricated composites were allowed for testing to examine its mechanical, wettability, and moisture properties. It has been observed that, in both cases, hybrid composites showed improved mechanical properties when compared to the individual fiber composites. The wettability test was carried out by using the contact angle measurement technique. All composites in both cases, hybrid or single showed contact angle less than 90°, which is associated with the composite hydrophilic surface properties. The moisture analysis stated that all the composites responded for moisture absorption up to 96 h and then remained constant in both cases. Hybrid composites absorbed less moisture than individual fiber composites.

Development and surface characterization of a bis(aminotriazoles) derivative based renewable carbon paste electrode for selective potentiometric determination of Cr(III) ion in real water samples

Regarding the Cr(III) importance in the industrial, environmental, and even biological systems, development of highly selective and sensitive Cr(III) sensor is a challenge. In this work, a new carbon paste electrochemical sensor containing a synthesized bis(aminotriazoles) derivative namely 1,3-bis[4-amino-5-benzyl-1,2,4-triazol-3-ylsulfanyl]propane (BABTSP) as the Cr(III) selective ionophore was described. Factors affecting sensor’s response were studied and optimized. The proposed sensor exhibited a Nernstian slope of 20.05 ± 0.35 mV decade−1 covering broad linear range of 1.0 × 10−8−5.0 × 10−2 mol L−1 and detection limit was 8.0 × 10−9 mol L−1 for 3 months over pH range of (2.3–5.2) and fast response time (<10 s). The proposed sensor was selective for Cr(III) ions that was confirmed by separate solution method (SSM) and fixed interference method (FIM) . The sensor was precise and reproducible (RSD% range = 0.8–2.45) and effectively used in potentiometric titration of Cr(III) against EDTA and in diverse water samples analysis with recovery data of 96.08–100.2%. The lipophilicity of the applied ionophore was investigated through contact angle measurement technique and average contact angle was 127.59° that resulted in sensor’s mechanical stability. To study the response mechanism and morphology of the prepared sensor, scanning electron microscope (SEM), energy dispersive X-ray (EDX) and FT-IR spectroscopy were used.

On the interpretation of contact angle for geomaterial wettability: Contact area versus three-phase contact line

Several techniques are available to characterise the wettability of porous rocks wherein the contact angle measurement technique has gained popularity, especially in tight rocks. Recent studies in surface science however raise an important issue on contact angle measurement and its theoretical analysis - whether the contact angle is controlled by the properties of the substrate area underneath the droplet or by the properties of the substrate at the circumference forming the three-phase contact line. This important issue has not been discussed in geomaterial contact angle characterisation despite its significant importance.We, therefore, conducted a series of experiments to study the role of contact area and three-phase contact line on dictating the contact angle. The experiments considered the material heterogeneity (i.e. clay, organic matter, and acrylic), surface roughness and geometry, and its patterns. We also used a new approach using interferometry to investigate the contact angle localisation.The results of this study revealed that the formation of the contact angle is only dictated by the three-phase contact line and not the contact area. No change in contact angle was observed when different materials or surface geometries were introduced under the droplet. The results also suggested that an increase in roughness can lead to erroneous contact angle measurements due to localisation of the contact angle and changes in the three-phase contact line point. The results further showed that the surface pattern plays a major role in contact angle measurement and must be considered if present. Finally, the combined understanding of the results indicated that the current contact angle measurements of geomaterials might carry significant error and that additional methodologies for determining their surface wettability should be used.

The effects of electrodeposition parameters on the wetting behavior of ceria coatings

Ceria coatings were electrodeposited on copper substrates; the effects of applied current density, bath concentration and bath temperature on the morphological, structural and wetting properties of the coatings were investigated. To do so, scanning electron microscopy, X-ray diffractometry, Fourier transform infra-red spectroscopy and static contact angle measurement techniques were used. The results showed that, increasing the applied current density, decreasing the bath concentration and temperature lead to the formation of thick coatings with small crystallite sizes and fine morphologies including many cracks. Moreover, it was observed that application of high applied current density or concentrated bath results in the formation of coating with more hydrophilic character while bath temperature does not influence the coating wetting behavior significantly. Although as-deposited coatings exhibited hydrophilic character, their behavior changed to hydrophobic one (especially in case of thick coatings) as a result of long exposure to room atmosphere and hydrocarbon adsorption. The rate of hydrocarbon adsorption was higher in the case of coatings with finer morphologies and more cracks.

Development of polyurethane-based superhydrophobic coatings on steel surfaces.

In this study, a superhydrophobic coating on steel surface has been developed with polyurethane, SiO2 nanoparticles and hexadecyltrimethoxysilane by using a spin-coating technique. Characterization of the coated steel surface was done by using the contact angle measurement technique, scanning electron microscopy and Fourier transform infrared spectroscopy. With a water tilt angle of 4° ± 2° and static contact angle of 165° ± 5°, the coated surface shows a superhydrophobic and self-cleaning nature. Chemical, thermal, mechanical stability tests and droplet dynamic studies were done to evaluate performance of the coating. Excellent self-cleaning, anti-fogging and anti-corrosion properties of coated steel surfaces make them ideal for industrial applications. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.

Development of stain resistant, superhydrophobic and self-cleaning coating on wood surface

In this work, hydrophilic (Dalbergia sissoo) wood has been modified into a superhydrophobic wood through simple immersion method using titanium dioxide (TiO2) nanoparticles and perfluorooctyltriethoxysilane (PFOTS). Wettability and surface topography of modified wood were characterized by contact angle measurement technique and scanning electron microscopy (SEM). Functional groups present on the modified wood surface were analysed by Fourier transform infrared spectroscopy (FTIR). Modified wood shows the excellent repellency to water and liquids with surface tension of more than 47 mN/m, with a static contact angle of more than 150° and tilt angle of less than 10°. Additionally, mechanical, thermal and chemical stability tests were also performed to evaluate wetting properties of superhydrophobic wood under harsh conditions. Furthermore, modified wood exhibits excellent self-cleaning and stain resistant properties, which makes it suitable for domestic and industrial applications.