Formulation Of Coatings Research Articles

Acrylic polyol/silicone coating corrosion protection analysis using electrochemical impedance spectroscopy

Purpose – The purpose of this paper is to develop different combinations of acrylic polyol and silicone resins with various weight ratios and to test the coating properties using electrochemical impedance spectroscopy (EIS). Design/methodology/approach – The performance properties such as coating resistance, capacitance, dielectric constant, water uptake and diffusion coefficient were evaluated using EIS with exposure to 3.5 per cent NaCl solution for 60 days. Findings – The binders developed in this study were coated on cold rolled steel plates. The dry film thickness was found to be in the range of 50 microns. From EIS results, it was found that Acrylic polyol sample with 30 weight per cent of silicone exhibits the best properties, as it has high coating resistance in the range of 109 Ohms for the full period of exposure, whereas all other samples showed poor performance with the exposure time. For these samples, the parameters measured such as the coating resistance of the samples decreased while the coating capacitance, percentage of water uptake and diffusion coefficient of the samples increased after being exposed to corrosive solution for 60 days. The coatings developed by 0, 10 and 60 weight per cent silicone showed high coating capacitance on the first day of exposure, and these systems failed early during the exposure. The water uptake percentage and diffusion coefficient of all samples were found to be less than 50 per cent and below 10-11 cm2 s−1, respectively. An optimum cross-linking between the resins is considered as the main contribution for the best performance shown by the sample that consists of 30 weight per cent of silicone in acrylic matrix that provides maximum barrier properties of the coating. Originality/value – Developing coatings using hybrid binders (silicone resin and acrylic polyol resin) is new area of research. This will explore more research in the formulation of novel coatings.

Development of an antimicrobial urinary catheter to inhibit urinary catheter encrustation

Background: Encrustation of urinary catheters is a frequent problem in patients with long-term indwelling catheters colonised with urease-positive bacteria such as Proteus mirabilis. Catheter blockage may follow catheter encrustation, potentially leading to systemic infection. Prevention of encrustation is difficult and avoidance of recurrence often unsuccessful. One possible preventative strategy is to use a catheter with an antimicrobial surface and development and assessment of such a surface was the aim of this research. Methods: Initial experiments assessed the antimicrobial activity of silicone impregnated with plant-derived antimicrobials and triclosan using agar diffusion. The longevity of activity of each antimicrobial silicone was examined over a period of 11 weeks following soaking individual pieces of antimicrobial silicone in an artificial urine solution before using agar diffusion to test remaining antimicrobial activity. Live/Dead staining of bacteria colonising the surface of each antimicrobial silicone was employed to determine the bactericidal properties of each antimicrobial silicone. Selected antimicrobial silicones were subsequently evaluated for their ability to prevent catheter encrustation in an in vitro bladder model. Results: Results showed that antimicrobial activity was obtained using 1% triclosan-impregnated silicone and that this antimicrobial activity was long-lasting (up to 11 weeks). Use of a dip coat silicone formulation, containing 0.2% triclosan, proved effective at delaying catheter encrustation with P. mirabilis metabolites in vitro. In 8 out of 13 independent experiments using dip-coated catheters, no catheter blockage occurred over 7 days, whilst all control catheters blocked during this period. Only on one occasion was delayed encrustation not evident with the treated catheters. Conclusions: In summary, a dip-coat silicone containing triclosan proved effective in preventing in vitro catheter encrustation caused by P. mirabilis infection. Further studies with triclosan silicone dip coat formulation are warranted, including those that investigate potential host cell toxicity and long-term benefits following its application to indwelling urinary catheters in clinical settings.

Rice Husk ash as Flatting Extender in Cellulose Matt Paint

The high silica content of rice husk ash (RHA) promotes its attractiveness as an abundant, cheap and renewable resource for various industrial applications such as surface coatings formulation. This study investigated the applicability of rice husk ash (RHA) as a flatting extender in cellulose matt paint and compared its flatting effect with those of two commercial extenders; fumed silica (the standard flatting agent) and silica flour. RHA was obtained by controlled incineration of rice husks at a temperature of 6500C and duration of 4hrs. The granular ash was then ground and sieved to obtain RHA flour with a particle size of ~32microns used in the formulation of the cellulose paints. Cellulose paint produced with fumed silica of 20μm-particle size was the reference standard while a sample produced with 0% extender served as the Control. The gloss values of the dry films of the paints were measured with a gloss meter at 200 angle of reflectance and their matt values calculated from their gloss values. The results showed that all three extenders substantially reduced the gloss levels of the cellulose paint samples with a resultant corresponding increase in their matt values. Although the flatting agents displayed varied degrees of flatting effect, their matt values were all over 100% higher than that of the Control. Fumed silica was highest in flatting performance, followed closely by RHA while silica flour ranked third. This trend was evident in the matt values (%) of 98.2±0.00, 94.7±0.06 and 86.9±0.11 obtained for cellulose matt paints produced with fumed silica, RHA and silica flour respectively. The Control had the lowest matt value of 42.9% showing its glossy nature due to the absence of a flatting agent.

Influence of magnesium hydroxide on thermal decomposition of intumescent fire-retardant epoxy coatings

Intumescent fire-retardant epoxy (IFR-EP) coatings including ammonium polyphosphate (APP), pentaerythritol (PER), melamine (MEL), magnesium hydroxide (MH), epoxy resin (EP) and polyamide resin (PA) were prepared. Thermal decomposition processes of the pure EP-PA, APP, PER, MEL and MH by thermogravimetric analysis (TGA) technique indicate that the decomposition temperature ranges of EP-PA, APP, PER and MEL are properly consistent with the intumescent mechanism of flame retardants. Thermal decomposition of IFR-EP coatings shows that 15 parts per hundred parts of resin MH is more appropriate to be selected in the formulation of IFR-EP coatings. Kinetic analysis of the TGA data based on the Kissinger methods revealed that activation energy could be used as an important parameter to judge the thermal decomposition process. The conversion dependencies of the activation energy plot show the complex effect of MH content on the thermal decomposition process of IFR-EP coatings.

Protection efficacy of gloves against components of the solvent in a sprayed isocyanate coating utilizing a reciprocating permeation panel.

Determine protection effectiveness of 5-mil natural rubber latex (0.13-mm), 5-mil nitrile rubber (0.13-mm), and 13-mil butyl rubber (0.33-mm) glove materials against solvents present in a commonly used automotive clear coat formulation using a novel permeation panel. The latex and nitrile gloves were the type commonly used by local autobody spray painters. Glove materials were tested by spraying an automotive clear coat onto an automated reciprocating permeation panel (permeation panel II). Temperature, relative humidity, and spray conditions were controlled to optimize clear coat loading homogeneity as evaluated by gravimetric analysis. Solvent permeation was measured using charcoal cloth analyzed by the National Institute for Occupational Safety and Health 1501 method. Natural rubber latex allowed 3-5 times the permeation of solvents relative to nitrile rubber for all 10 solvents evaluated: ethyl benzene, 2-heptanone, 1-methoxy-2-propyl acetate, o-xylene, m-xylene, p-xylene, n-butyl acetate, methyl isobutyl ketone, petroleum distillates, and toluene. There is a distinct behavior in solvent permeation before and after the coating dry time. Solvent permeation increased steadily before coating dry time and remained fairly constant after coating dry time. Butyl was not permeated by any of the solvents under the conditions tested. Commonly used 5-mil thick (0.13-mm) latex and nitrile gloves were ineffective barriers to solvents found in a commonly used clear coat formulation. Conversely, 13-mil (0.33-mm) butyl gloves were found to be protective against all solvents in the clear coat formulation.

New finishing possibilities for producing durable multifunctional cotton/wool and viscose/wool blended fabrics.

This research work focuses on the development of a one-bath functional finishing procedure for imparting durable multifunctional properties such as easy care, soft-hand, antibacterial and/or ultra violet (UV) protection to cotton/wool and viscose/wool blends using diverse finishing combinations and formulations. In this study finishing agents such as reactant resin, silicon softeners, 4-hydroxybenzophenone, triclosan, and pigment colorant were selected using magnesium chloride/citric acid as a mixed catalyst and the pad-dry microwave fixation technique. The results reveal that enhancement in the imparted functional properties are governed by type of the finished substrate as well as nature and concentration of finishing formulation components. The finished fabrics still retained high level of functionalities even after 15 consecutive laundering. Surface morphology and composition of selected samples were investigated using scan electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The mode of interactions was also investigated. Practical applications for multifunctionlization of cellulose/wool blended fabrics are possible using these sorts of proper finishing formulations and unique finishing application method.

The effect of alginate-based edible coatings enriched with essential oils constituents on Arbutus unedo L. fresh fruit storage

The effect of coating Arbutus unedo fresh fruit with alginate-based edible coatings enriched with the essential oils compounds (EOC) eugenol (Eug) and citral (Cit) was studied. The minimum inhibitory concentrations (MIC) against the main postharvest pathogens were determined for Eug and Cit giving values of 0.10 and 0.15 (w/v), respectively. Twelve formulations of edible coatings were used: sodium alginate (AL) was tested at 1 and 2% (w/v) with incorporation of Eug and Cit at MIC and double MIC or their combination at MIC. Arbutus berries were dipped in those solutions for 2min, and then stored at 0.5°C. Control consisted of uncoated fruit. On days 0, 14 and 28, samples were taken to perform physicochemical and biochemical analysis [color CIE (L*, h°), firmness, soluble solids content (SSC), weight Loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels]. Results showed that edible coatings of 1% AL were the best to maintain most quality attributes of the commodity through storage at 0.5°C. The incorporation of Cit and Eug into the alginate edible coatings improved the coatings in most cases, AL 1% + Eug 0.20% and AL 1% + Cit 0.15% + Eug 0.10% being those that better preserved sensory and nutritional attributes and reduced microbial spoilage. Thus, these coatings may be useful for improving postharvest quality and storage life of fresh arbutus fruit.

Powder Coating Formulations with Pseudomonas fluorescens M45 Enhance the Emergence Rate and Healthy Stand Establishment of Sesame in Disease-Conducive Soil

Sesame is a major cooking oil crop in Korea. One of the primary problems in sesame cultivation is low healthy stand establishment due to the occurrence of seedling rot and damping-off resulting from a complex of soil-borne pathogens in the field. To address the problem, the bioformulation of Pseudomonas fluorescens M45 was prepared in powder form using clay and vermiculite, and was evaluated for its effect on biological control of soil-borne pathogens in sesame cultivation. In the petri dish trial, the emergence rate was overall good (> 92%) regardless of seeds being pelleted and/or M45-treated. In both pot and field trials containing disease-conducive soils, seed-pelleting substantially reduced emergence rate, whereas seed-pelleting with M45 significantly improved the emergence rate (> 26%). The emergence rate of sesame seeds treated with the strain M45 was greater than 30% regardless of seed pelletization. We also found that M45r colonized in the roots at the density of 1.6×10 5 cfu/g. With aid of the bioformulation, however, root colonization of the strain was significantly increased to 4.0×10 6 cfu/g. The powder formulation with strain M45 enhanced the rate of healthy stand establishment in disease-conducive soil. Therefore, bioformulation with strain M45 is a promising method to overcome problems associated with the successive cultivation of sesame.

Characterization of Coatings of New Technology for Corrosion Prevention

Nowadays, there are various types of new technology coatings used in the corrosion protection. These include from organic solvent-based formulations to water solvent-based and solvent free (high content of solids). Regardless of their nature, these protection systems must present properties to ensure good performance against various environmental conditions.In this work, factors such as degradation, corrosion resistance and the effect of type of coatings formulation are investigated, by implementing contact angle tests and accelerated weathering. Thus, qualitative information about the systems is obtained. For this purpose the samples are exposed to different solutions which simulate the corrosive environments, according to ASTM B117 -11 and ASTM D 5894-10 standards. Also, electrochemical techniques as electrochemical impedance spectroscopy (EIS) and electrochemical frequency module (EFM), were employed to provide quantitative information about the process of degradation and corrosion.The visual defects usually appear when the resistance of the coatings tends to a value ≤ 1x106 Ohm/cm2. The obtained information allows to enquire the process of degradation of the systems and their level of protection, and the relationship between the electrochemical parameters and visual assessment.

Carbamazepine solubility enhancement in tandem with swellable polymer osmotic pump tablet: A promising approach for extended delivery of poorly water-soluble drugs

Elementary osmotic pump (EOP) is a unique extended release (ER) drug delivery system based on the principle of osmosis. It has the ability to minimize the amount of the drug, accumulation and fluctuation in drug level during chronic uses. Carbamazepine (CBZ), a poorly water-soluble antiepileptic drug, has serious side effects on overdoses and chronic uses. The aim of the present study was to design a new EOP tablet of CBZ containing a solubility enhancers and swellable polymer to reduce its side effects and enhance the patient compliance. Firstly, a combination of solubilizing carriers was selected to improve the dissolution of the slightly soluble drug. Then, designing the new EOP tablet and investigating the effect of different variables of core and coat formulations on drug release behavior by single parameter optimization and by Taguchi orthogonal design with analysis of variance (ANOVA), respectively. The results showed that CBZ solubility was successfully enhanced by a minimum amount of combined polyvinyl pyrrolidone (PVP K30) and sodium lauryl sulfate (SLS). The plasticizer amount and molecular weight (MW) together with the osmotic agent amount directly affect the release rate whereas the swellable polymer amount and viscosity together with the semi-permeable membrane (SPM) thickness inversely influence the release rate. In addition, the tendency of following zero order kinetics was mainly affected by the coat components rather than those of the core. Further, orifice size does not have any significant effect on the release behavior within the range of 0.1 mm to 0.8 mm. In this study we report the successful formulation of CBZ-EOP tablets, which were similar to the marketed product Tegretol CR 200 and able to satisfy the USP criterion limits and to deliver about 80% of CBZ at a rate of approximately zero order for up to 12 h.

Thermoset coatings from epoxidized sucrose soyate and blocked, bio-based dicarboxylic acids.

A new 100% bio-based thermosetting coating system was developed from epoxidized sucrose soyate crosslinked with blocked bio-based dicarboxylic acids. A solvent-free, green method was used to block the carboxylic acid groups and render the acids miscible with the epoxy resin. The thermal reversibility of this blocking allowed for the formulation of epoxy-acid thermoset coatings that are 100% bio-based. This was possible due to the volatility of the vinyl ethers under curing conditions. These systems have good adhesion to metal substrates and perform well under chemical and physical stress. Additionally, the hardness of the coating system is dependent on the chain length of the diacid used, making it tunable.

Development of a transparent hydrorepellent modified SiO2 coatings for glazed sanitarywares

The formulation of innovative transparent hydrorepellent coatings is strongly motivated in order to satisfy the market request and necessity to improve the cleanability of the sanitarywares. A lot of attention is devoted to the use of cheap precursors, low temperature synthesis process and industrial scalability potentiality. In this framework, in the present paper the set-up of the deposition of modified SiO2 coatings on glazed ceramic supports by spraying technique was reported. Several solutions were formulated using as precursor tetraethylorthosilicate (TEOS) and co-precursor methyltriethoxysilane (MTES) in different molar ratios (i.e. 50:50, 25:75, 75:25), in suitable solvents and mixture of solvents (i.e. H2O, ethanol). The influence of the process parameters (i.e. precursors ratio, solvents, catalyser, annealing temperature) on the properties of the produced coatings was deeply investigated by means of scanning electron microscopy (SEM), simultaneous thermogravimetric and differential analyses (TG–DTA), infrared spectroscopy (FT-IR), X-Ray diffraction (XRD) and Vickers microhardness. Their hydrophobic behaviour was tested by the measurements of the static water contact angles and the chemical and stain resistance by the conformity to some tests of the standard UNI 4543. The obtained coatings were amorphous, homogeneous, uniform, thin (average thickness 300 nm), crack-free, leading to an improved hardness value of the glazed ceramic support (4.47 GPa vs 3.68 GPa for the coated and uncoated substrates, respectively), and allowed to improve both the hydrophobic behaviour and the chemical and stains resistance of the glazed sanitaryware supports, on the basis of the standard UNI 4543. The best hydrophobic performances were revealed in the case of coatings prepared starting from acidic catalysis derived precursor solutions. Moreover, the highest water contact angle values were detected for lower temperatures annealing, due to the methyl groups preservation, in agreement with the FT-IR and TG–DTA findings.

Corrosion Inhibitor Patents in Industrial Applications – A Review

Corrosion affects the quality of the environment, the durability of the infrastructure assets and industrial equipments. Therefore, it is crucial using corrosion engineering control methods and techniques, in particular safe "green" e.g. environmental friendly corrosion inhibitors that will extend the life of the infrastructure saving large expenses in materials equipment and structures. This review presents an analysis of patents on corrosion inhibitors developed for aqueous systems, steel reinforced concrete, acid pickling operations, oil industry and additives in the formulation of protection coatings.

Influence on Pore Structure of Micro/Nanofibrillar Cellulose in Pigmented Coating Formulations

Nano and microfibrillated cellulose (NFC and MFC, respectively, collectively termed MNFC) is known to interact strongly with water, related to its high polarity and surface area. The swelling behaviour acts to form a gel with high water retention properties. The observation that nanocellulose could possibly be used in paper or other coating formulations, as a co-binder, for example, raises a question about the possible effects it could have on coating pore structure. In this study, we analyse the pore structure of pigmented coatings, liquid absorption and permeability, in respect to the influence of partially substituting traditional co-binder carboxymethyl cellulose with MNFC. The contrast between polar water and non-polar liquid, such as alkane, is used to probe the water interactive and extractable in-coating (internal) gel-formation properties of the nanocellulosic materials. These contrasting liquids are important in many processes, such as offset printing, but also in respect to exposure of coatings in general to environmental factors in application. Results show that permeability to liquid water is dramatically reduced when nanocellulosic material is present, though water can permeate by diffusion through the nanocellulose gel network. Long timescale exposure to water during absorption leads to extraction of any soluble salts remaining after the chemical treatment of the fibrillar material during production. Inert alkane, on the other hand, can absorb and permeate freely without interactive hindrance from the nanocellulose, with no extractive effect. Such a construct could in principle be considered for use as an oil-water differential membrane or for slow release concepts in aqueous systems by loading soluble deliverable materials within the nanocellulosic gel.

Hot-melt co-extrusion for the production of fixed-dose combination products with a controlled release ethylcellulose matrix core

In this study, hot-melt co-extrusion was evaluated as a technique for the production of fixed-dose combination products, using ethylcellulose as a core matrix former to control the release of metoprolol tartrate and a polyethylene oxide-based coat formulation to obtain immediate release of hydrochlorothiazide. By lowering the concentration of the hydrophilic additive polyethylene oxide in the plasticized ethylcellulose matrix or by lowering the drug load, the in vitro metoprolol tartrate release from the core was substantially sustained. The in vitro release of hydrochlorothiazide from the polyethylene oxide/polyethylene glycol coat was completed within 45 min for all formulations. Tensile testing of the core/coat mini-matrices revealed an adequate adhesion between the two layers. Raman mapping showed no migration of active substances. Solid state characterization indicated that the crystalline state of metoprolol tartrate was not affected by thermal processing via hot-melt extrusion, while hydrochlorothiazide was amorphous in the coat. These solid state characteristics were confirmed during the stability study. Considering the bioavailability of metoprolol tartrate after oral administration to dogs, the different co-extruded formulations offered a range of sustained release characteristics. Moreover, high metoprolol tartrate plasma concentrations were reached in dogs allowing the administered dose to be halved.

Direct Measurement of Colloidal Interactions between Polyaniline Surfaces in a UV-Curable Coating Formulation: The Effect of Surface Hydrophilicity/Hydrophobicity and Resin Composition

The interactions between polyaniline particles and polyaniline surfaces in polyester acrylate resin mixed with 1,6-hexanediol diacrylate monomer have been investigated using contact angle measurements and the atomic force microscopy colloidal probe technique. Polyaniline with different characteristics (hydrophilic and hydrophobic) were synthesized directly on spherical polystyrene particles of 10 μm in diameter. Surface forces were measured between core/shell structured polystyrene/polyaniline particles (and a pure polystyrene particle as reference) mounted on an atomic force microscope cantilever and a pressed pellet of either hydrophilic or hydrophobic polyaniline powders, in resins of various polymer:monomer ratios. A short-range purely repulsive interaction was observed between hydrophilic polyaniline (doped with phosphoric acid) surfaces in polyester acrylate resin. In contrast, interactions between hydrophobic polyaniline (doped with n-decyl phosphonic acid) were dominated by attractive forces, suggesting less compatibility and higher tendency for aggregation of these particles in liquid polyester acrylate compared to hydrophilic polyaniline. Both observations are in agreement with the conclusions from the interfacial energy studies performed by contact angle measurements.

Preparation and Application of Conductive Textile Coatings Filled with Honeycomb Structured Carbon Nanotubes

Electrical conductive textile coatings with variable amounts of carbon nanotubes (CNTs) are presented. Formulations of textile coatings were prepared with up to 15 wt % of CNT, based on the solid weight of the binder. The binders are water based polyacrylate dispersions. The CNTs were mixed into the binder dispersion starting from a commercially available aqueous CNT dispersion that is compatible with the binder dispersion. Coating formulations with variable CNT concentrations were applied on polyester and cotton woven and knitted fabrics by different textile coating techniques: direct coating, transfer coating, and screen printing. The coatings showed increasing electrical conductivity with increasing CNT concentration. The coatings can be regarded to be electrically conductive (sheet resistivity < 103 Ohm/sq) starting at 3 wt% CNT. The degree of dispersion of the carbon nanotubes particles inside the coating was visualized by scanning electron microscopy. The CNT particles form honeycomb structured networks in the coatings, proving a high degree of dispersion. This honeycomb structure of CNT particles is forming a conductive network in the coating leading to low resistivity values.

Formulation and evaluation of press coated tablets of salbutamol sulphate for time controlled release

The objective of the present study was to formulate and evaluate a press coated pulsatile drug delivery system of salbutamol sulphate in order to attain a time controlled release for treatment of nocturnal asthma. The core was prepared by direct compression, while press coating technique was used in coating the outer layer there by preparing a press coated tablet. The immediate release core formulations comprised of salbutamol sulphate and disintegrants like crospovidone, croscarmellose sodium and sodium starch glycolate in different ratios with the drug. The outer coat formulations were prepared using a hydrophilic (HPMC) and hydrophobic (EC) polymer of similar viscosity. The polymers were reviewed individually for their influence on lag time further obtaining the lag time using polymer combinations were assessed by employing central composite design. All the preliminary trials were evaluated for various post compression parameters along with the dissolution study that was performed using USP paddle method at 50 rpm in 0.1 N HCl and phosphate buffer pH 6.8. The formulation containing 300 mg of EC N50 and 75‑100 mg of HPMC E50 may be regarded as the minimum quantity required in outer press coat so as to attain a predetermined lag time of 6 h. Key words: Central composite design, ethylcellulose, hydroxypropyl methylcellulose, press coat, salbutamol sulphate, time controlled release

Testing of Glove Efficacy against Sprayed Isocyanate Coatings Utilizing a Reciprocating Permeation Panel

Modify a permeation panel to evaluate dermal protective clothing for resistance to sprayed coatings with minimal variability in spray paint loading across the test panel. Determine isocyanate protection effectiveness of natural rubber latex (5 mil or 0.13mm), nitrile rubber (5 mil or 0.13mm), and butyl rubber (13 mil or 0.33mm) glove materials against a commonly used automotive clear coat formulation. The latex and nitrile gloves were the type used by the local autobody spray painters. Glove materials were tested by spraying paint onto an automated reciprocating permeation panel (permeation panel II). Temperature, relative humidity, and spray conditions were controlled to optimize paint loading homogeneity as evaluated by gravimetric analysis. Isocyanate permeation was measured using 1-(2-pyridyl)-piperazine-coated fiber-glass filters analyzed by a modified version of the OSHA 42/PV2034 methods. Latex exhibited a higher permeation rate compared with nitrile for isocyanates (1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate monomers) and both materials presented permeation at all of the time points suggesting a fast isocyanate breakthrough. Butyl material exhibited no permeation or breakthrough for isocyanates under the tested conditions. The spray application at 69±8°F was optimally homogeneous at 45±0.5mg weight of dry clear coat per 5cm(2). The permeation panel II is a reliable method to assess dermal protective clothing performance against polymerizing coatings. Commonly used 5-mil (0.13-mm) latex and nitrile gloves were determined to be ineffective barriers against the isocyanates found in a commonly used clear-coat formulation while butyl gloves were protective.

Guidelines to measurements of reproducible contact angles using a sessile-drop technique

The current broad interest in wetting characterization of solid surfaces is driven by recent advances in the formulation of surfaces and coatings that are superhydrophobic, superhydrophilic, oleophobic, oleophilic and so on. Unfortunately, the contact angle data presented in many publications raise some concerns among the surface chemists and physicists who work with contact angle measurement techniques on a regular basis. In those articles, best practices are often ignored, and the data presented are limited to the static contact angles measured for small droplets, a few times smaller than typically recommended. The reported contact angles are neither advancing nor receding, and their reproducibility in different laboratories is therefore questionable. In this note, guidelines to measurements of reproducible and reliable advancing and receding contact angles are summarized.