Search Results (130)

Triatoma infestans is one of the primary vectors of Chagas disease. This vector has developed increasing resistance to pyrethroids, the main insecticides used for its control. Recent studies have highlighted the repellent and lethal effects of Cannabis sativa on insects, suggesting its potential use in pest management. Based on this, we hypothesize that C. sativa could be a viable bioactive for controlling T. infestans. To test this hypothesis, acetone and ethanol extracts were obtained from the inflorescences of C. sativa L. (Deep Mandarine variety) using sonication. These extracts were analyzed through gas chromatography and high-performance liquid chromatography. The repellent and lethal effects of the extracts were evaluated on fifth-instar nymphs of T. infestans from a laboratory colony, as well as on the beneficial non-target species, Apis mellifera. The most abundant terpenes identified were β-caryophyllene and β-pinene, with concentrations exceeding 100 ppm in both extracts. Cannabidiol and Δ⁹-tetrahydrocannabinol were the predominant cannabinoids. Both extracts exhibited maximum lethal activity 48 h after insect contact, with the acetone extract demonstrating a potency five times greater than the ethanolic extract. Binary combinations of C. sativa extracts with major terpenes showed dose-dependent interactions against T. infestans, ranging from strong synergy (e.g., AE + β-caryophyllene, CI = 0.06–0.17) to marked antagonism (e.g., AE + E-ocimene, CI = 1.60–4.80). Furthermore, the acetone extract showed a more effective repellent action compared to the ethanol extract, even outperforming N,N-Diethyl-meta-toluamide (DEET, positive control). At a concentration of 25 µg/cm² for 60 min, the acetone extract achieved a 100% repellent effect, whereas DEET required a concentration of 50 µg/cm² to achieve the same effect. Unlike imidacloprid (positive control), neither extract showed toxicity to adult A. mellifera at the evaluated doses. Full article

Per- and polyfluoroalkyl substances (PFASs) are highly chemically stable synthetic compounds. They are widely used in industrial and commercial sectors due to their ability to repel water and oil, thermal stability, and surfactant properties. However, this stability results in environmental persistence and bioaccumulation, posing significant health risks as PFASs eventually find their way into environmental media. Key PFAS compounds, including PerFluoroOctanoic Acid (PFOA), PerFluoroOctane Sulfonic acid (PFOS), and PerFluoroHexane Sulfonic acid (PFHxS), have been linked to hepatotoxicity, immunotoxicity, neurotoxicity, and endocrine disruption. In response to the health threats these substances pose, global regulatory measures, such as the Stockholm Convention restrictions and national drinking water standards, have been implemented to reduce PFAS exposure. Despite these efforts, a lack of universally accepted definitions or comprehensive inventories of PFAS compounds hampers the effective management of these substances. As definitions differ across regulatory bodies, research and policy integration have become complicated. PFASs are broadly categorized as either perfluoroalkyl acids (PFAAs), precursors, or other fluorinated substances; however, PFASs encompass over 5000 distinct compounds, many of which are poorly characterized. PFAS contamination arises from direct industrial emissions and indirect environmental formation, these substances have been detected in water, soil, and even air samples from all over the globe, including from remote regions like Antarctica. Analytical methods, such as primarily liquid and gas chromatography coupled with tandem mass spectrometry, have advanced PFAS detection. However, standardized monitoring protocols remain inadequate. Future management requires unified definitions, expanded monitoring efforts, and standardized methodologies to address the persistent environmental and health impacts of PFAS. This review underscores the need for improved regulatory frameworks and further research. Full article

Anti-icing glass is particularly important for applications where ice formation can pose safety risks or impair functionality. The challenge of anti-icing modification for glass lies in maintaining water repellency while addressing the issue of transparency and durability. In this work, leveraging the robustness and wear resistance of inorganic/organic composite materials, a highly transparent coating, with strong adhesive properties to glass substrates and repellency to liquids has been developed. Briefly, 3-glycidoxypropyl polyhedral oligomeric silsesquioxane (GPOSS) is employed as a precursor to fabricate a high-strength, high-transparency coating through modification with acrylic acid and perfluorooctyl acrylate. The inorganic component imparts strength and wear resistance to the coating, while the organic component provides hydrophobic and near oleophobic features. Furthermore, a custom-built mechanical test instrument evaluated the absolute value of the de-icing shear force. The results reveal that at −20 °C, the fluorinated modified coating only exhibit a minimum de-icing pressure of 40.3 kPa, which is 75% lower than the unmodified glass substrate. As-prepared coating exhibits a transmittance of up to 99% and can endure a high-pressure water impact of 30 kPa for 1 min without cracking. Compared to existing anti-icing coating methods, the core innovation of the fluorinated GPOSS-based coating developed in this study lies in its inorganic/organic composite structure, which simultaneously achieves high transparency, mechanical durability, and enhanced anti-icing performance. Full article

Superhydrophobic surfaces with a low liquid–solid contact time have huge application prospects in anti-icing, corrosion-resistant, self-cleaning, etc. Significant attempts have been devoted to reducing the contact time through altering the hydrodynamics of the process through which the droplet contacts the superhydrophobic surface. However, these works are rarely considered to be related to the influence of environmental conditions (e.g., the pH of the droplet, salinity of the droplet, droplet viscosity, and supercooled droplet impact). Here, we report various superhydrophobic cone arrays (SCAs) with low droplet impact contact times under various conditions (pH of the droplet, salinity of the droplet, droplet viscosity, droplet temperature, etc.). We demonstrate that the low contact time of the droplet impacting cone-arrays can be optimized via the critical Weber number, pillar-to-pillar spacing, and pillar height (e.g., 11.1, 350 μm, and 300 μm, respectively). The lowest droplet contact time of ~6 ms, which is reduced by more than 60% compared to conventional bouncing, can be achieved. In addition, directional pancake bouncing behaviors can achieve the largest horizontal displacement (85% of the droplet size, ~3 mm) on a tilted SCA with optimal tilt angles. These findings offer insights into the interface effect for controlling wetting that would extend the practical applications, e.g., liquid repellency, anti-corrosion, anti-icing, heat transfer, etc. Full article

The performance of oil–water coalescence separation elements currently fails to meet the increasing demands of the oily wastewater treatment industry. To address this challenge, a series of fiber coalescing filters were developed through an underwater superoleophobic modification process using a simple impregnation technique. The effect of varying surface wettability on the separation efficiency of oil-in-water (O/W) emulsions stabilized with surfactants was investigated. The results demonstrate that, after undergoing underwater superoleophobic modification, the separation efficiency of the fiber filter material improved by 33.9%, the pressure drop was reduced by 46.1%, and the steady-state quality factor increased by 83.3%. Building upon these findings, an oil-repellent pore size gradient structure was introduced for the coalescence separation of surfactant-stabilized oil-in-water emulsions. This structure exhibited outstanding characteristics, including a low pressure drop and a high-quality factor. Furthermore, when processing emulsions stabilized with surfactants such as OP-10 (nonionic), CTAB (cationic), and SDS (anionic), the structure maintained high separation efficiencies of 93.6%, 96.4%, and 97.2%, respectively, after 10 cycles. Finally, based on experimental data and theoretical analysis, a separation mechanism for oil–water coalescence using superoleophobic pore size gradient filtration materials is proposed. This structure demonstrates significant potential for widespread application in liquid–liquid separation technologies. Full article

In this study, polymer films based on the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl with repellent N,N-diethyl-3-methylbenzamide were prepared and used as functional textile coatings. The high sorption activity of oxides with respect to N,N-diethyl-3-methylbenzamide (63–239 mg/g) allows for the use of these compounds as repellent carrier materials, and their mixture with polyacrylates allows for the formation of functional coatings–polymer films. Scanning electron microscopy and Fourier transform infrared spectroscopy results revealed that the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl were successfully anchored in the polyacrylate structure, and the FTIR spectra confirmed the presence of repellent molecules. The thermal diffusion parameters of N,N-diethyl-3-methylbenzamide were also calculated via thermogravimetric analysis and high-performance liquid chromatography with diode array detection. The highest thermal diffusion rates and concentrations were observed for the material with Al₂O₃ (up to 148.3∙10⁻⁹ mol at 200 °C), and lower values for ZrO₂ and SiO₂-phenyl (up to 15.2∙10⁻⁹ mol and 34.3∙10⁻⁹ mol at 200 °C, respectively). The heat flux parameter J_f was also calculated according to Onsager’s theory and Fourier’s law. The release of repellent from polymeric materials can be achieved by applying less heat than that required to reach the boiling point of N,N-diethyl-3-methylbenzamide. Full article

The quality control of insect repellents contributes to the population’s health since these products prevent mosquito bites and vector-borne diseases. In this study, we developed and validated a novel analytical method using high-performance liquid chromatography with a diode array detector (HPLC-DAD) for the quantification of icaridin in insect repellent lotions. The analysis was performed on a phenyl chromatographic column 150 × 4.6 mm, 3.5 μm and stabilized at 30 °C. The detection of icaridin was achieved at 4.5 min with a 20 μL injection volume of the samples. The active ingredient was extracted from the lotion samples with isopropanol and water (50:50 v/v) and then diluted to the working concentration at 0.6 mg/mL with the mobile phase. The calibration curve was linear in the concentration range of 0.1 to 1.2 mg/mL. The method was robust, specific and precise (relative standard deviations—RSD < 2%). The accuracy of the method was demonstrated by icaridin recovery. The limit of detection and quantification were 0.03 mg/mL and 0.1 mg/mL, respectively. The present report puts forward a novel analytical method for the quantification of icaridin, contributing to improving the quality control and efficacy of marketed formulations and their different presentations such as lotions, gels and sprays, demonstrating its good applicability. Full article

Highly transparent anti-smudge coatings are attractive for diverse fields due to their inherent repellency against various contaminants and the ability to keep surfaces clean. In this work, a novel fluorine-free anti-smudge coating system was developed by using poly(dimethysiloxane), tris(hydroxymethyl) aminomethane, and isophorone diisocynate to synthesize a hexa-functional coating precursor and utilizing hexamethylene diisocyanate trimer as a curing agent. The resultant anti-smudge coatings are highly transparent and can be applied to various substrates. These coatings exhibit repellency against water, hexadecane, ink, pump oil, and crude oil and show self-cleaning performance in air and oily environments. Moreover, they display anti-ink ability and can be employed to reduce bacterial contamination. Of note, they can endow substrates with protection against corrosion from strong acids, strong bases, salt solutions, and even aqua regia. The developed coatings also show potential for controllable liquid transport. Moreover, these versatile coatings are mechanically robust, demonstrating tolerance against abrasion, impact, and bending and also exhibiting excellent adhesion to various substrates, indicative of their availability for widespread applications. Full article

Calcium alginate hydrogel is one of the most widely used materials for drug-carrier beads used in drug-delivery systems. In this study, we developed a new method to improve the encapsulation efficiency of ingredients, such as medicines, in calcium alginate hydrogel beads. In the gold standard method, the hydrogel beads are prepared in the liquid phase. In contrast, in the new method, to enhance the encapsulation efficiency, the hydrogel beads are prepared in the gas phase using a water-repellent surface. In brief, a droplet of sodium alginate aqueous solution is rolled on a water-repellent surface with CaCl₂ powder, a cross-linking agent. This process leads to the direct attachment of CaCl₂ powder to the droplet, resulting in the formation of spherical hydrogel beads with high mechanical strength and higher encapsulation efficiency than beads prepared by previous methods. The hydrogel beads exhibit similar permeability for glucose, a model for low-molecular-weight medicines, to those prepared by previous methods. These results show that the new method is promising for the preparation of calcium alginate hydrogel beads for drug-delivery systems. Full article

In this work, the simple fabrication of a new superhydrophobic magnetic sponge based on CNTs, NiFe₂O₄ nanoparticles, and PDMS was investigated. CNTs were synthesized by chemical vapor deposition (CVD) on a nickel ferrite catalyst supported on aluminum oxide (NiFe₂O₄/Al₂O₃). The synthesis of nickel ferrite (NiFe) was accomplished using the sol–gel method, yielding magnetic nanoparticles (43 Am²kg⁻¹, coercivity of 93 Oe, 21–29 nm). A new superhydrophobic magnetic PU/CNT/NiFe₂O₄/PDMS sponge was fabricated using a polyurethane (PU) sponge, CNTs, NiFe₂O₄ nanoparticles, and polydimethylsiloxane (PDMS) through the immersion coating method. The new PU/CNT/NiFe₂O₄/PDMS sponge exhibits excellent superhydrophobic/oleophilic/mechanical properties and water repellency (water absorption rate of 0.4%) while having good absorption of oil, olive oil, and organic liquids of different densities (absorption capacity of 21.38 to 44.83 g/g), excellent separation efficiency (up to 99.81%), the ability to be reused for removing oil and organic solvents for more than 10 cycles, and easy control and separation from water using a magnet. The new PU/CNT/NiFe₂O₄/PDMS sponge is a promising candidate as a reusable sorbent for collecting oil and organic pollutants and can also be used as a hydrophobic filter due to its excellent mechanical properties. Full article

Surface wettability, the interaction between a liquid droplet and the surface it contacts, plays a key role in influencing droplet behavior and flow dynamics. There is a growing interest in designing surfaces with tailored wetting properties across diverse applications. Advanced fabrication techniques that create surfaces with unique wettability offer significant innovation potential. This study investigates the wettability transition of laser-textured anisotropic surfaces featuring shark skin-inspired microstructures using four post-processing methods: spray coating, isopropyl alcohol (IPA) treatment, silicone oil treatment, and silanization. The impact of each method on surface wettability was assessed through water contact angle measurements, scanning electron microscopy (SEM), and laser scanning microscopy. The results show a transition from superhydrophilic behavior on untreated laser-textured surfaces to various (super)hydrophobic states following surface treatment. Chemical treatments produced different levels of hydrophobicity and anisotropy, with silanization achieving the highest hydrophobicity and long-term stability, persisting for one year post-treatment. This enhancement is attributed to the low surface energy and chemical properties of silane compounds, which reduce surface tension and increase water repellence. In conclusion, this study demonstrates that post-processing techniques can effectively tailor surface wettability, enabling a wide range of wetting properties with significant implications for practical applications. Full article

This paper aims to verify the effect of water-soluble hydrophobisations on cementitious composites such as concrete (S1) and cement-bonded particle boards (S2). The research was focused on the water-soluble hydrophobisations based on methylsilanolate (MS), a mixture of silanes and siloxanes (SS) and alcohol with the addition of nano-silica (N). The results provide a comprehensive overview of the benefits and effectiveness of water-soluble hydrophobisations in the context of building materials, outlining a direction towards the development of new, more environmentally friendly solutions in the construction industry. For this reason, alternative raw materials (brick recyclate and brick dust) were used for S1 substrate preparations. How the water-soluble hydrophobisations, including hydrophobisations with the addition of nano-silica (N), affect the process of water evaporation during hydration and the resulting water repellence of the S1 and S2 substrates were experimentally verified through a series of tests, e.g., measurement of the contact angle and depth of water penetration under pressure. The evaluation of the effect of hydrophobisations on the resistance of substrate to aggressive gaseous and liquid environments was observed by the determination of the resistance to carbonation and sulphation processes and the resistance of the concrete to aggressive liquid media (10% H₂SO₄, 10% CH₃COOH). Although the hydrophobisations did not have a significant effect on some aspects of S1, such as the resistance to carbonation and sulphate attack, improvement was observed in other areas, such as the quadrupling increase in contact angle of the surface and 9 mm decrease in water pressure penetration into the concrete substrate. Full article

Infectious diseases that cause illness and/or death in humans can be contracted from mosquito bites. A viable and alternate method of personal protection that can lower the danger of human exposure to mosquito-borne diseases is the use of plant-based repellents. Using a high-throughput screening system, the current work examined the toxicity, contact irritancy, and spatial repellency of Andrographis paniculata crude extract and its fractions against Aedes aegypti, Anopheles minimus, and An. dirus. Five fractions (i.e., F1, F2, F3, F4, and F5) were separated from the crude extract by column and thin layer chromatography and analyzed using high-performance liquid chromatography and mass spectrometry. The major active compounds identified from F3 and F5 were 4-deoxy-11,12-didehydroandrographolide and andrographolide. Three concentrations (1.0, 2.5, and 5.0%) for each of the crude extracts and the five fractions were individually impregnated on nylon netting strips and evaluated against the three mosquito species. Results showed that the highest contact irritancy was elicited by the crude extract at 5% concentration against Ae. aegypti (43.70% escaped). Results of the spatial activity index (SAI) showed that fractions F3 and F5 at 2.5% demonstrated the strongest repellency against Ae. aegypti (SAI = 0.84) and An. minimus (SAI = 0.83), respectively. Both the crude extract and its components did not cause any knockdown or mortality. These findings suggest that fractionation of A. paniculata extracts is valuable in assessing their spatial repellent efficacy against mosquitoes. Fractions F3 and F5 hold promise as natural mosquito repellents and could contribute to developing effective mosquito control strategies. Full article

In this article, a novel electromagnetic diaphragm pump design controlled by an Arduino NANO microcontroller is proposed to pump liquid inside the pumping chamber completely separated from mechanical and transmission parts. The prototype is primarily based on alternating the polarity of two electromagnets that attract or repel a permanent magnet located on a flexible diaphragm. The system hardware layout is completed by electronic components:. an Arduino NANO microcontroller created by Atmel, Headquarters San Jose, California. and display within the cabinet to control the polarization of the electromagnets and exhibit the temperature inside the pump. The electromagnetic pump and control system consist of innovative approaches as a solution for the treatment of unclean water and integration with solar panel systems. In addition, the measurement tests of the electromagnetic pump, including the temperatures of electromagnets and the quantity of the pumped liquid within the chamber, indicate a dependence on the selected speed of the electromagnet’s polarization. The electromagnetic pump achieves high efficiency as a combination of the temperature and the amount of liquid that can be regulated and controlled by the switching speed of the electromagnet’s polarization. Full article

The effect of extreme water repellency, called the lotus effect, is caused by the formation of a Cassie–Baxter state in which only a small portion of the wetting liquid droplet is in contact with the surface. The rest of the bottom of the droplet is in contact with air pockets. Instrumental methods are often used to determine the textural features that cause this effect—scanning electron and atomic force microscopies, profilometry, etc. However, this result provides only an accurate texture model, not the actual information about the part of the surface that is wetted by the liquid. Here, we show a practical method for estimating the surface fraction of texture that has contact with liquid in a Cassie–Baxter wetting state. The method is performed using a set of ethanol–water mixtures to determine the contact angle of the textured and chemically equivalent flat surfaces of AlSI 304 steel, 7500 aluminum, and siloxane elastomer. We showed that the system of Cassie–Baxter equations can be solved graphically by the wetting diagrams introduced in this paper, returning a value for the texture surface fraction in contact with a liquid. We anticipate that the demonstrated method will be useful for a direct evaluation of the ability of textures to repel liquids, particularly superhydrophobic and superoleophobic materials, slippery liquid-infused porous surfaces, etc. Full article