Hydrophobic Behavior Research Articles

Impact of voltage variation on topography, hydrophobicity, and corrosion behavior of the CeO2-TiO2 nanocomposite coating on AM60B Mg alloy prepared by plasma electrolyte oxidation

Abstract A superhydrophobic oxide layer on AM60B magnesium alloy was created by using a plasma electrolytic oxidation (PEO) technique and subsequent surface modification. PEO was applied in an electrolyte with/without CeO2-TiO2 nanoparticles (NPs) by two different voltages of 350 and 450 V. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM) were used to evaluate the roughness and morphology of the surface. Water contact angles on the surface were measured to investigate the surface wettability. Potentiodynamic polarization tests in a 3.5 wt.% NaCl solution were used to assess the corrosion resistance of the coating. Also, the FE-SEM images showed that increasing applied voltage, decreases the numbers and size of the pores on the surface. Results showed that applying PEO, increased the corrosion resistance of the bare AM60B because corrosion rate (C.R.) decreased from 1.523805 (bare AM60B) to 1.432107 mpy (PEO-450 V). Furthermore, using CeO2-TiO2 NPs effectively enhanced the corrosion resistance of the bare AM60B by decreasing the corrosion rate from 1.523805 to 1.286469 mpy.

Natural zeolite/PVC beads for the removal of ammonium ions from water: Wettability, particle size, strength, hydrophilicity and equilibrium behaviour

This study developed an improved method for removing ammonium ions from water using natural zeolite/PVC beads. Research gaps relating to the impact of particle size, wettability, robustness, hydrophobicity and equilibrium behaviour were addressed. It was surmised that manipulation of the formation of natural zeolite/PVC beads will improve the performance of these composite materials. First it was noted that water-saturated sorbents exhibited higher ammonium ion exchange rates than dried beads. An air nozzle was proposed as a potential solution for controlling particle size. To control bead particle size, a range of airflow rates passed through an optimised 3D printed nozzle design. Bead diameters from below 0.5 mm up to 2 mm were obtained, with higher airflow rates promoting the growth of smaller beads. 0.5–1 mm beads also were characterised by lower attrition rates compared to larger ≈ 2.7 mm particles (54 to 57 % change) and had almost the same kinetics exchange rate as their regular unbound zeolite powder counterparts (0.4 to 13.5 % difference). The equilibrium data was in the shape of a linear isotherm, which suggested that the ammonium ions were equally dispersed throughout the sorbent and the aqueous solution. Finally, the use of amphipathic copolymer (Pluronic F127) improved the exchange kinetics of the dry beads (42 to 160 % change) but also weakened the structural integrity of the zeolite composites (284 to 647 % change depending on the analysed composites).

Experimental investigations on metallization in the surface modified additively manufactured plastic substrates using DC sputtering

The application of copper surface coating to plastic structures offers numerous advantages, including high thermal and electrical conductivity, improved mechanical properties, good corrosion resistance, decorative applications, and enhancements in working temperatures. Besides these advantages, producing plastic structures with 3D printing and applying surface coating enables the final structures to become functional plastic structures adaptable to different fields. In this study, 3D plastic structures were produced using the fused deposition modeling method. Pristine, dichloromethane dipping, dichloromethane vapor, cold oxygen plasma, and mechanical abrasion surface treatments were applied to determine the optimal surface treatment between copper and the plastic substrate before copper coating. Subsequently, copper coating on plastic structures was completed using the DC sputtering technique. The surface topography, optical, electrical, and structural properties of the produced plastic structures were examined. According to X-ray diffraction analysis results, the (111), (200), (220), and (311) crystal planes confirm the presence of copper. The electrical conductivity values of the plastic structures reached 7.87 × 105 S/m. Contact angle measurement results indicate that the applied surface treatments increased the contact angles to 88.309°, leading the coated plastic structures to exhibit a more hydrophobic behavior.

Improving composite performance by cellulose-based Ceiba petandra fiber coating

ABSTRACT Composites are expected to have good properties, such as water and moisture resistance. They require fibres that can bind well to a polymer matrix. Therefore, modification on a fibre surface was performed to improve hydrophobic behaviour and fibre–matrix interfacial bonds. The modification was done by conducting Acrylated Epoxidized Soybean Oil coating. In this study, Ceiba pentandra fibre was modified using alkali treatment and coating. The results revealed that double treatment of alkali and coating produced the best Ceiba pentandra fibre properties. The lowest water absorption of the alkali-coated Ceiba pentandra fibre composite was 3.17%, and the tensile strength increased by 52.78%, indicating an increase in the fibre–matrix interfacial bond. The coating was effective to prevent water absorption and increase composite tensile strength. Alkali coating on Ceiba pentandra fibre, besides alkali treatment, can be an alternative to improve a fibre’s performance.

Thickness dependent crystallinity, hydrophilicity, and surface microtexture in CaF2 thin films deposited via thermal evaporation method

This study investigates the deposition and characterization of CaF₂ thin films with thicknesses ranging from 40 to 320 nm, fabricated via thermal evaporation onto glass substrates. X-ray diffractometry (XRD) revealed that increased film thickness leads to enhanced crystallinity, with larger crystallite sizes and reduced lattice strain. Wettability analysis demonstrated a transition from hydrophobic behavior (contact angle ∼70° for 40 nm) to hydrophilic behavior (contact angle ∼52° for 320 nm) as film thickness increased. Surface morphology, examined via atomic force microscopy (AFM), showed a significant reduction in surface roughness in thicker films, with smoother, more coalesced surfaces observed for films over 160 nm. Monofractal analysis further confirmed the evolution of surface microtexture, with thicker films exhibiting higher uniformity and reduced surface complexity. These findings provide critical insights into optimizing CaF₂ thin films for applications in optics, electronics, and surface coatings, where improved crystallinity and surface properties are essential.

Enhanced properties of methyl hydroxyethyl cellulose films with arabinoxylans-rich extract from brewer's spent grain

Environmentally friendly methyl hydroxyethyl cellulose (MHEC)-based films added with different amounts (10-30 wt.%) of an arabinoxylans-rich extract (AxRE) obtained from brewer's spent grain (BSG) were developed by the solvent casting method. Some decrease in mechanical properties of films was shown with increasing AxRE content. Addition of AxRE led to a decrease in tensile strength to 23.0-33.7 MPa which are typical of commodity plastics used in the packaging industry. AxRE increased the thermal stability of MHEC-based films, as evidenced by a slight increase in melting point observed through differential scanning calorimetry (DSC) together with a delay in the thermodegradation profile obtained by thermogravimetric analysis (TGA), with onset degradation temperatures above 300 °C for all compositions. Additionally, films with AxRE showed higher hydrophobic behavior, increasing water contact angle from 58.6° (neat MHEC) up to 67.8° for films containing 20 wt.%-AxRE and a decreasing in the moisture content of MHEC films (5.6%) to 4.2% for films containing 10 wt.%-AxRE. Interestingly, the arabinoxylans-rich extract significantly increased the antioxidant activity of MHEC-based films with values up to 50% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition in films with 20 wt.%-AxRE. The obtained films show potential for active packaging, given that they have demonstrated to provide important antioxidant activity.

Evaluation of optical, thermal and hydrophobic properties of sustainable stilbene-based benzoxazines for high-performance utilization

Currently there is a growing interest in the field of photosensitive benzoxazines synthesized from sustainable raw materials. An attempt has been made to synthesize nine structurally different benzoxazines through Mannich condensation reaction. The formation of the expected structure of the synthesized benzoxazine monomers were ascertained using spectroscopic methods. The ring-opening polymerization of benzoxazines was studied using DSC and found that THS-imp benzoxazine monomer exhibits the lowest value of curing temperature (Tp) of 179oC than the rest of the benzoxazine monomers. Thermal stability of polybenzoxazines were analyzed using thermogravimetric analyzer. Among the different polybenzoxazines studied, poly(THS-a) possesses the higher thermal stability with char yield of 53 % than that of other benzoxazines. The band gap values of benzoxazines calculated from optical studies are ranged between 3.92 and 4.71 eV. The hydrophobic behavior of the polybenzoxazines assessed using the water contact angle obtained from goniometer for both neat polymer matrix and benzoxazine coated cotton fabric. Results from the water contact angle infer that the benzoxazines coated cotton fabric exhibited 152°, which shows the superhydrophobic behavior. The corrosion resistant properties of all the polybenzoxazines coated over MS specimen has been tested. Among them poly(THS-pfsa) and poly(THS-imp) have higher Icorr value and corrosion inhibition efficiency of 99 %. Data obtained from different studies indicate that the benzoxazines developed from sustainable stilbene can be utilized in the form of coatings, adhesives, sealants, and matrices for composites for wide range of industrial and engineering applications, where high thermal stability and are required.

Efficient synthesis of highly hydrophobic lignin nanoparticles and their application as nano fillers for multifunctional composite membranes

Controlling the hydrophobic behaviors of lignin nanoparticles (LNPs) is crucial and advantageous for their application as film Nano Fillers, yet it poses a significant challenge. Herein, we successfully developed a novel method for the preparation of LNPs with highly hydrophobic behaviors using ternary deep eutectic solution (DES)-H2O systems. The resulting LNPs exhibit a significantly reduced content of hydrophilic groups on their outer surface, leading to a zeta potential value of only −4.9 mV, and up to 140.0° of water contact angle (WCA). Afterwards, a “Dissolution-Restructuration” mechanism was proposed to explain the formation of the prepared LNPs. Firstly, DES demonstrates superior H-bonding capabilities, facilitating the complete disruption of inter- and intramolecular H-bonding in lignin, and resulting in the formation of a highly homogenized lignin network. Subsequently, the DES system undergoes compromise after adding water, triggering the reformation of both inter- and intramolecular H-bonding and π-π interactions. Consequently, lignin orderly self-assembles into LNPs with highly hydrophobic characteristics. Especially, using the as-prepared LNPs as Nano fillers, a series of LNPs-containing polyvinyl alcohol (PVA) films were successfully fabricated, exhibiting exceptional hydrophobic behaviors (with contact angles reaching up to 124.0°). Furthermore, the mechanical strength, UV-shielding capabilities, and biodegradability of the PVA films are significantly enhanced. This study introduces a sustainable and efficient approach for the synthesis of hydrophobic LNPs, thereby facilitating the broadening of applications for lignin-based functional composite film materials.

Development of carboxymethyl cellulose/starch films enriched with ZnO-NPs and anthocyanins for antimicrobial and pH-indicating food packaging

Active packaging, which can monitor food freshness and extend the shelf life, has gained significant attention in recent years. This study aims to develop a novel carboxymethyl cellulose (CMC)/starch/anthocyanins/ZnO active films with enhanced properties and specific functionalities. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that the addition of anthocyanins and nano-ZnO particles (ZnO-NPs) led to heterogeneous microstructures and a slight decrease in the crystallinity. Fourier transform infrared spectroscopy (FTIR) indicated that there were no chemical interactions among film components. Active films containing ZnO-NPs exhibited improved ductility, as well as enhanced light barrier and water resistance properties. Notably, a shift from hydrophilic to hydrophobic behavior of the films was observed with high ZnO-NP content, as evidenced by a significant increase in the water contact angle (from 63.44° to 114.22°). Furthermore, the presence of only 1 % ZnO-NPs resulted in efficient inhibition of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) growth. Moreover, active films containing both anthocyanins and ZnO-NPs were highly sensitive to pH changes in buffer solutions (pH 2–11). Based on the results, a recommended film formulation for future active packaging applications is a 80:20 CMC/starch blend with 3 % ZnO-NPs and 0.1 g anthocyanins.

Chemical Synthesis and Characterization of Fatty Acid-Capped ZnO Nanoparticles

In the current study, ZnO nanoparticles were obtained using a chemical process employing zinc acetate as the precursor, followed by thermal processing in air. To prevent agglomeration and increase the stability of ZnO nanoparticles, two unsaturated acids (e.g., elaidic acid and linoleic acid) and two saturated acids (e.g., stearic acid and lauric acid) were selected as capping agents. ZnO nanoparticles were investigated before and after surface modification with different fatty acids. Structural and morphological analyses of the samples were performed using FTIR and RAMAN spectroscopy, X-ray diffraction, SEM microscopy, and wetting capacity. Characterization studies revealed that the synthesized ZnO nanoparticles present well-defined crystalline structures, with crystallite sizes varying between 26 and 28 nm, and the average particle size was in the range of 10–55 nm (depending on the type of fatty acids used). The goniometric analysis followed the wetting capacity of the sample surface. The study results reveal that the capping agents have a considerable impact on the surface modification of the nanoparticles by increasing the contact angle. By producing nanoparticles with hydrophobic behavior, there is the possibility of opening up future research for their use in various applications across many industrial fields.

UiO-66 Inspired Superhydrophobic Coatings Fabricated from Discarded Polyester/Spandex Textiles.

We report on a method for synthesizing superhydrophobic coatings using a UiO-66 metal-organic framework (MOF) with discarded polyester/Spandex fabrics as raw materials. Unlike traditional recycling techniques that involve separating non-poly(ethylene terephthalate) (PET) components, our approach directly uses blended polyester/Spandex fibers. Discarded polyester/Spandex fabrics were exposed to an alkaline depolymerization process to produce disodium terephthalate (Na2BDC), which is a known linker for UiO-66 synthesis. We conducted experiments under two different conditions involving different amounts of ethanol. We found that with a small amount of ethanol, the resulting UiO-66 structure, when assembled on top of a polyester/Spandex substrate, exhibited a water contact angle of ≥150°─a superhydrophobic behavior. When using larger amounts of ethanol, we noted a hydrophobic behavior with a water contact angle of ∼139°. As a control, we performed the same experiments but using discarded 100% polyester fabrics as raw materials, which resulted in a superhydrophilic behavior. We attribute the superhydrophobic behavior of the UiO-66 coatings, produced from the polyester/Spandex fabrics, to the presence of hydrophobic compounds generated by the chemical degradation of Spandex. Our approach introduces a pathway for upcycling discarded textiles into superhydrophobic coatings.

Production of protein-epigallocatechin gallate conjugates using free radicals induced by ultrasound and their gelation behavior

In this study, free radicals generated by ultrasound were used to prepare conjugates of food proteins (soybean protein isolates, sodium caseinate and gelatin) with epigallocatechin gallate (EGCG). The changes in free amino and sulfhydryl group contents were used to confirm the occurrence of conjugation. The formation of covalent interactions on surface hydrophobicity, functional groups, structures, thermal stability, and gelation behavior of three proteins were investigated. The results showed that conjugation led to decrease in free amino and sulfhydryl group contents, reduction in the intensity of amide A and fluorescence intensity, and increase in β-fold content. The conjugation also resulted in a decrease in surface hydrophobicity and thermal stability of soybean protein isolates and sodium caseinate, but an increase in the surface hydrophobicity and thermal stability of gelatin. Furthermore, the covalent bonding between proteins and EGCG improved gel strength, water holding capacity, and resulted in a denser and more compact microstructure.

Rare earth-doped ceramic coatings: Analysis of microstructure, mechanical properties, and slurry Erosion resistance using high pressure-high velocity oxy-liquid fuel deposition

The high pressure-high velocity oxy liquid fuel (HP-HVOLF) is a current industry-adopted thermal spraying technique for developing high melting point powder coating over surfaces. In the current manuscript, the rare earth (La2O3/CeO2/Er2O3–0.3 wt%. each) doped and without rare earth doped carbide (WC-10Co-4Cr) coatings have been deployed on stainless steel (SS410) via HP-HVOLF process. The comparison among the properties of the substrate, without rare earth coating and rare earth oxides doped coatings have been characterized by conducting mechanical, microstructural, and slurry jet erosion analysis. The results show that the hardness, modulus of elasticity, and flexural strength of the cermet coating are considerably higher for rare earth-doped coatings than those without rare earth-doped coatings and substrates (SS410). The EDX (energy dispersive X-ray spectroscopy) has recognized the occurrence of different elements on the surface together with rare earth. Moreover, its compounds such as Co3W3C and W2C were inveterate using X-ray diffraction (XRD) measurements. The porosity level of the rare earth doped, and un-doped coatings are obtained to be less than 1 % and≥1 to ≤2 % respectively. Moreover, the rare earth-doped cermet coated surface shows hydrophobic behavior with a maximum water contact angle (WCA) of ≈129.4°. Furthermore, the slurry jet behavior of rare earth doped coating shows high wear resistance as compared to without RE doped coatings, indicating its potential for robust performance under erosive conditions.

Electron beam induced graft polymerized anti oil-fouling biaxial polypropylene membrane with harsh environment tolerance

The intrinsic hydrophobic behavior of biaxial-oriented polypropylene microporous membrane limits its broad application area by leading serious membrane fouling. An environment-friendly, practical, and facile to large-scale prepared surface modification process is designed to enhance the membrane wettability and oil-fouling. By employing electron beam radiation, acrylic acid, and polyvinyl alcohol in the pre-irradiation-induced graft polymerization process, a micro-nano structure was developed and the surface roughness was increased from 66.5 nm to 99.3 nm. Enhancing the grafting ratio further reduces the pore size of the final modified membrane from 54 nm to 25 nm, which is significantly smaller than the size of the emulsified oil droplet. By modifying the morphological and structural characteristics of the grafted membrane, excellent oil-fouling resistance features are attained with UWOCA value 161° and separation efficiency of 99.3 %. Moreover, the theoretical explanations for hydrophilicity and oil-fouling resistance of modified membranes are also developed using DFT calculations and the Hermia model, which shows alignment with experimental data. Consequently, considerable improvements in wettability, thermal and mechanical behavior are obtained by this facial surface modification approach, which could further broaden the modified membrane's applications area in membrane separation technology while lengthening its service life.

Rapid ion pair-based surfactant-assisted liquid-liquid microextraction with solidification of floating organic drop for simultaneous spectrophotometric determination of selected anionic dyes in food samples

Ion pair-based surfactant-assisted liquid-liquid microextraction with solidification of floating organic drops has been developed to extract Allura red (AR), tartrazine (TAR), and fast green (FG) prior to spectrophotometric determination. Cetyltrimethylammonium bromide (CTAB) was employed as ion-pairing agent to enhance the hydrophobic behavior of anionic dyes. 1-undecanol and ethanol were used as the extraction and dispersion solvents, respectively. The dyes were quantitatively extracted in the presence of KCl (0.15 mol L−1) at pH 4.0. The method exhibits wide linearity (15.0–1500.0 μg L−1 for AR, 35.0–2000.0 μg L−1 for TAR, and 3.0–1200.0 μg L−1 for FG) with preconcentration factors of 19.6, 20.1, and 19.9, respectively. The detection limit was 3.7. 9.5, and 0.83 μg L−1 for AR, TAR, and FG, respectively. The relative standard deviation did not exceed 2.1 %. The procedure was applied for the determination of these dyes in food samples.

Sand blasting for hydrophobic surface generation in polymers: Experimental and machine learning approaches

Wettability is a crucial surface feature of polymers due to their numerous interaction-destined applications. This study focuses on the application of sand blasting process for investigating the wettability of polymeric materials to produce hydrophobic behavior. Four different polymeric materials, Acrylonitrile Butadiene Styrene (ABS), Poly(methyl methacrylate) (PMMA), Polypropylene (PP), and Polycarbonate (PC) underwent sand blasting with varying process parameters, following a comprehensive plan for the design of experiments. Subsequent analyses included surface roughness measurement and wettability tests, supplemented by scanning electron and confocal microscopy observations to gain deeper insights into the blasted surfaces. A predictive model based on a machine learning algorithm was developed using the backpropagation technique to correlate the surface treatment parameters to surface roughness and wettability indexes. From the experimental results sand blasting proved to be efficient in creating hydrophobic surfaces on all the tested materials. The developed neural network demonstrated high fitting degrees between the predicted and measured values. ABS exhibited the most hydrophobic behavior and emerged as a strong candidate for further investigations.

Synthesis of suspension stabilizers for isolation fluids by response surface methodology and study of their properties

In order to solve the problem of unstable settling of isolation fluid at high temperatures, high-temperature-resistant suspension stabilizers for isolation fluids were prepared. Using the free radical aqueous solution method with 2-acrylamido-2-methylpropanesulfonic acid (AMPS), YX-1 (a monomer containing an amide group) as the main chain of the molecule, and N-Vinylpyrrolidone (NVP) and DX-2 (monomer containing hydrophobic groups) as the side chains of the molecule. We innovate the suspension stabilizer synthesis process, the synthesis conditions of the suspension stabilizer were optimized by using the one-factor experimental design and response surface analysis. The elemental composition and structure of the polymer suspension stabilizers were tested and analyzed by using X-ray spectroscopy (XPS), infrared spectroscopy (FTIR) and nuclear magnetic resonance hydrogen spectroscopy (H NMR). The hydrophobic aggregation behaviour of the polymer molecular chains was demonstrated from a microscopic point of view using fluorescence spectroscopy tests and size analysis of polymer molecular aggregates. Oscillation experiments on the isolation solution with suspension stabiliser showed that the hydrophobic groups contained in the polymers can undergo the effect of joining and bridging, and can also form a strong spatial network structure at 220°C, leading to the enhanced elasticity of the isolation fluid, which helps to alleviate the sedimentation of barite. Sedimentation stability and compatibility were evaluated for the isolation fluid containing suspension stabilizers. It was found that the isolation solution suspension performance is good under the condition of 90–220℃, its density difference is less than 0.10 g/cm3. It can also effectively prevent the contact contamination of the drilling fluid cement slurry, which is conducive to the improvement of the quality of the deep well cementing.

Thermoresponsive blends formed by poly(N‐vinylcaprolactam) and thermoplastic polyurethane

AbstractPoly(N‐vinylcaprolactam) (PNVCL) is a thermoresponsive polymer, which presents a transition from hydrophilic to hydrophobic behavior close to the physiological temperature, being promising for biomedical applications. However, the production of finished products with PNVCL is difficult due to its high mechanical fragility in the solid state. In the present work, in order to prepare a thermoresponsive film with good mechanical properties, a blend of PNVCL with thermoplastic polyurethane (TPU) was prepared. Three compositions of PNVCL/TPU were studied with mass proportions of 90/10, 70/30, and 50/50, respectively. The films were flexible, miscible and presented different thermoresponsive behaviors, with changing from transparent to opaque varying from 31 to 40°C. Contact angle analysis showed significant changes in the hydrophilicity of the films' surfaces with temperature variation. Moreover, it was possible to induce a change in solid films from transparent to opaque by varying the temperature and verify the reversibility of this change. In addition, tensile tests were carried out, which proved, for PNVCL/TPU blends, the reduction of film brittleness with TPU increase. To the best of our knowledge, it is the first work that presents thermoresponsive properties of solid films formed by a blend of PNVCL and TPU.

Microwave-assisted rapid synthesis of ZnO multipod-BiOBr heterojunction on recycled PET plastic waste for photocatalytic degradation of oily wastewater

Heterojunctions based on ZnO multipod and BiOBr were developed on the floating recycled polyethylene terephthalate (PET) and they were used to investigate the photocatalytic degradation of hexane in water emulsion. Characterizations of the synthesized ZnO-BiOBr-PET photocatalysts was performed using XRD, FESEM, EDX, BET/BJH, FTIR, UV-Vis DRS, PL, WCA, and CV analyses. The FESEM results demonstrated that ZnO multipods have been synthesized during the very short time of microwave heating that effectively hosted the highly dispersed BiOBr nanoplates, particularly in the 15 %ZnO-5 %BiOBr-80 %PET sample. The BET/BJH analysis revealed the low surface areas for the synthesized samples, however, the sample with the highest ZnO multipod loading (15 %ZnO-5 %BiOBr-80 %PET) exhibited slightly enhanced surface area due to the highly dispersed BiOBr over the ZnO multipods. The fabricated samples displayed hydrophobicity and liquid marble like behaviour due to the presence of PET, while the variations in the percentages of ZnO and BiOBr strongly influenced the water contact angle. The formation of heterojunction between ZnO multipod and BiOBr was confirmed which lead to a shift in the visible light region, increased the light harvesting, and also reduced the charge carrier recombination in the composite sample of 15 %ZnO-5 %BiOBr-80 %PET. The ZnO-BiOBr-PET photocatalysts were tested for the photocatalytic degradation of hexane in a water emulsion and results indicated that 15 %ZnO-5 %BiOBr-80 %PET could degrade 92.1 % of initial hexane, retaining its performance over four successive runs with only an 11.7 % decrease in activity. Scavenger tests revealed that, in addition to hydroxyl radicals, superoxide also played a significant role in the photocatalytic degradation of hexane. This obervations indicate the efficient capturing and utilizing of O2 by this LMP even in non-oxygenated conditions.

Nanotechnological Antibacterial and Conductive Wound Dressings for Pressure Ulcer Prevention.

The development of pressure ulcers, associated with increased temperature and moisture in specific areas of the body, and the risk of microbial infections in patients lying in a static position for prolonged periods of time represents a serious issue in medicine. In order to prevent the formation of pressure ulcers, this work aims to present advanced nanostructured coatings developed by three research groups. Nanometric silver, ash and functionalized torrefied biomass were the basis for the treatment of wound dressings to improve thermal conductivity and antimicrobial properties of the conventional cotton gauzes. Each treatment was performed according to its own optimized method. The treated fabrics were characterized in terms of antimicrobial properties, heat transfer, morphology and hydrophobic behavior. The results demonstrated the effectiveness of the deposition treatments also in synergistic actions. In particular, the antibacterial efficacy was improved in all the samples by the addition of silver treatment, and the thermal conductivity was enhanced by around 58% with nanometric ashes. A further step of the study involved the designing of two multilayer systems evaluated using circuit models for determining the total thermal conductivity. In this way, both systems were designed with the aim to guarantee simultaneous efficacy: high antibacterial and hydrophilic properties at the skin level and more hydrophobic and conductive behaviors toward the external environment.