Hydrophobic Behavior Research Articles

Novel Design of Superhydrophobic and Anticorrosive PTFE and PAA + β - CD Composite Coating Deposited by Electrospinning, Spin Coating and Electrospraying Techniques.

A superhydrophobic composite coating consisting of polytetrafluoroethylene (PTFE) and poly(acrylic acid)+ β-cyclodextrin (PAA + β-CD) was prepared on an aluminum alloy AA 6061T6 substrate by a three-step process of electrospinnig, spin coating, and electrospraying. The electrospinning technique is used for the fabrication of a polymeric binder layer synthesized from PAA + β-CD. The superhydrophilic characteristic of the electrospun PAA + β-CD layer makes it suitable for the absorption of an aqueous suspension with PTFE particles in a spin-coating process, obtaining a hydrophobic behavior. Then, the electrospraying of a modified PTFE dispersion forms a layer of distributed PTFE particles, in which a strong bonding of the particles with each other and with the PTFE particles fixed in the PAA + β-CD fiber matrix results in a remarkable improvement of the particles adhesion to the substrate by different heat treatments. The experimental results corroborate the important role of obtaining hierarchical micro/nano multilevel structures for the optimization of superhydrophobic surfaces, leading to water contact angles above 170°, very low contact angle of hysteresis (CAH = 2°) and roll-off angle (< 5°). In addition, a superior corrosion resistance is obtained, generating a barrier to retain the electrolyte infiltration. This study may provide useful insights for a wide range of applications.

Antibacterial titanium dioxide coatings for CoCrMo orthopaedic implants

Periprosthetic joint infections (PJIs) still remain a severe complication after arthroplasty despite the significant advances in manufacturing materials in the orthopaedic field. The sol–gel based coating strategy is attracting interest for its multifaceted potential to design surfaces capable of exerting antibacterial properties. In this study, the sol–gel technique is employed to obtain a new class of titanium dioxide coatings doped with silver and gallium ions to minimize the adhesion and bacterial colonization on the CoCrMo surfaces. Uniform anatase titania coatings with hydrophobic behaviour and nanometer thickness (50–200 nm) were obtained by dipping CoCrMo samples in TiO2 sols with different compositions. The physicochemical characterization of coatings using EDS, GDOES, and ICP-OES confirmed the incorporation of doping agents. Antimicrobial assays were performed against Gram-positive S. aureus and Gram-negative E. coli bacteria, demonstrating a satisfying antibacterial activity. Furthermore, all the coatings tested showed no cytotoxicity and osteodifferentiation potential. Thus, the herein sol–gel strategy could represent a powerful tool for surface modification of CoCrMo-based materials for implantable devices.

Fabrication of superhydrophilic/underwater superoleophobic functionalized-nanoparticles/PVDF-supported thin film composite polyamide membranes for efficient water purification

For water treatment, membrane-based separation methods are very essential owing to long-term efficiency, high mechanical stability and durability. The filtration process with polymer-inorganic and organic composite is an outstanding strategy that enhances the properties of both inorganic materials such as thermal and mechanical stability and organic material including flexibility and processability of the membranes. Therefore, the surface wettability of the membranes is vital for pollutants separation. Here, the high hydrophobic behavior of polyvinylidene fluoride (PVDF) membranes is altered to superhydrophilicity and underwater superoleophobicity via single-step coating. This PVDF membrane has high molecular separation due to the ultrathin thickness and good controllable interlayer. In this study, the PVDF membrane was by interfacial polymerization coated with a polyamide (PAm) layer, modified alumina nanoparticles (Al-NPs), (aminopropyl)triethoxysilane (APTES), and folic acid (FA) through a chemical grafting reaction. The influence of the PAm and Al-APTES-FA content on the morphology, structure, antifouling, and superhydrophilicity of the PVDF-g-PAm@Al-APTES-FA membrane has been investigated which has enhanced the oil and salt rejection as well as filtration performance. Fourier Transform Infrared (FTIR) spectroscopy showed the specific functional groups from the obtained results indicating the successful preparation. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), and AFM (Atomic Force Microscope) techniques were conducted to observe the membrane surface morphology, roughness, and elemental adsorption after the filtration process. Furthermore, this modified PVDF membrane exhibited an excellent superoleophobicity with underwater oil contact angle (OCA~145°), and superhydrophilic visualization with water contact angle (WCA ~ 0°) after being functionalized. Additionally, the parameters of membrane performance such as permeate flux, heavy metal ions, oil and salts rejection, were assessed. The modified material on the PVDF membrane enhanced the membrane efficiency under high operating pressure of 10 bar with 53 LMH (L.m−2 h−1, while it is ≈0 for PVDF membrane), permeate flux, over 90 % salt rejection, and almost 100 % hydrocarbons and heavy metal ions rejection, owing to membrane surface changes, hydrophilicity, and roughness. This research will provide new insights on porous surface transformation to improve the separation and antifouling properties of PVDF membranes used in water purification.

Multifunctional Bioactive Scaffolds from ARX-g-(Zn@rGO)-HAp for Bone Tissue Engineering: In Vitro Antibacterial, Antitumor, and Biocompatibility Evaluations.

Advanced biomaterials are required with enhanced antibacterial and anticancer activities to obtain desirable biocompatibility during and after scaffold implantation in tissue engineering. Here, we report the development of a nanosystem by the hydrothermal method using different zinc (Zn) amounts and reduced graphene oxide (GO). Arabinoxylan, the nanosystem (Zn@rGO), and nanohydroxyapatite polymeric nanocomposites ARX-g-(Zn@rGO)/HAp were prepared by the free radical polymerization method, and porous bioactive scaffolds were fabricated via the freeze-drying technique. The structural, morphological, and elemental analyses of the bioactive scaffolds were conducted using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray analysis. The wetting behavior was studied by a water contact meter and swelling in aqueous and phosphate-buffered saline solutions at 37 °C. The degradation was also studied in the phosphate-buffered saline solution at 37 °C. The increase in Zn content increased the pore size, and hydrophobic behavior shifted to hydrophilic (AGZ-1 = 131.40° at 0 s and 120.60° at 10 s to AGZ-1 = 81.30° at 0 s and 69.20° at 10 s) with the increase in contact time. Maximum swelling was observed in deionized water (AGZ-1 = 52.87%, AGZ-4 = 90.20%), followed by phosphate-buffered saline (PBS; AGZ-1 = 44.80%, AGZ-4 = 67.90%) and electrolyte (AGZ-1 = 32.40%, AGZ-4 = 63.47%), and biodegradation in PBS media increased (AGZ-1 = 36.80%, AGZ-4 = 55.92%). Antimicrobial activities against severe infection-causing pathogens and antitumor activity against U87 cell lines showed exceptional results. Cell viability and cell proliferation studies were conducted against preosteoblast cell lines, and increased cell viability and proliferation were observed from AGZ-1 to AGZ-4. Antimicrobial and anticancer activities were enhanced with the increase of Zn content in the Zn@rGO system. The bioactive scaffolds with different formulations could be potential biomaterials to treat and regenerate defected bone tissue.

Water-tolerant solid polymer electrolyte with high ion-conductivity for simplified battery manufacturing in air surroundings

The humidity-sensitive electrolytes necessitate the stringent conditions of lithium battery manufacturing and, thus, increase the fabrication complexity and cost. We herein report a water-tolerant solid polymer electrolyte (WT-SPE) with high Li+ conductivity (2.08 × 10−4 S cm−1 at room temperature) and electrochemically stable window (up to 4.7 V vs Li/Li+), which utilizes moisture to initiate rapid polymerization and form dense structures to achieve a facile battery manufacturing in humid air without the need of a glovebox. Molecular dynamics simulations attribute this hydrophobic behavior to the hindered transfer of a water molecule in dense WT-SPE. A stable SEI layer composed of a polymeric framework and other organic/inorganic small molecular compounds contributes to the sustainable operation of batteries. As a result, the Li|WT-SPE|LiCoO2 cells manufactured in the air exhibit a high initial capacity of 192 mA h g−1 at 0.1C and an excellent capacity retention for 300 cycles at 1C. The great advantage significantly simplifies the battery assembly process in air environment and can also maintain good interfacial contact between an electrolyte and electrodes thanks to in situ initiated polymerization, which shows great superiority and promise in the alternatives of traditional liquid and polymer electrolytes for low-cost and facile fabrication of batteries in ambient atmosphere.

The effect of polyhedral oligomeric silsesquioxane fillers in non‐isocyanate polyurethane hybrid resins

AbstractPolyhedral oligomeric silsesquioxane (POSS) is added to poly(hydroxyurethane) (PHU) prepolymers to create hybrid PHUs (HPHUs) with enhanced mechanical and thermal properties. These hybrid materials were then further functionalized with 3‐Isocyanatopropyl(trimethoxy) silane (IPTMS) via the pendent hydroxyl bonds within the backbone of the polymers to obtain a final cured film comparable to conventional polyurethanes (PU), using less isocyanate‐functional material. The incorporation of POSS into PHU prepolymers to obtain HPHUs was supported by gel permeation chromatography, fourier tranform infrared spectroscopy (FTIR) and nuclear magnetic resonance analysis. Furthermore, the thermal degradation of the HPHUs was significantly improved with increasing POSS concentration compared to their PHU counterparts as the degradation temperatures at 50% weight loss increased from 263°C for the PHU to 341°C for the HPHU. Gel content tests in tetrahydrofuran (THF), water, and toluene were performed and gel contents of 87%–99% in THF were observed for the cured films. Water swelling, and contact angle tests confirmed that the POSS‐modified films exhibited hydrophobic behavior. Finally, mechanical properties of the cured films were investigated. The Young's modulus and tensile strength were improved with increasing POSS concentration (from 2.0 to 3.1 MPa and from 0.82 to 1.32 MPa, respectively) and elongations at break up to 41.6% were observed. When compared to a conventional PU sealant, the HPHU achieved a tensile strength that was two‐fold greater and a comparable elongation at break (increasing from 24.8% to as high as 41.6%).

Leaf surfaces and neolithization - the case of Arundo donax L.

Arundo donax L. (Arundinoideae subfamily, Poaceae family) is a sub-tropical and temperate climate reed that grows in arid and semi-arid environmental conditions, from eastern China to the Mediterranean basin, suggesting potential adaptations at the epicuticular level. A thorough physical-chemical examination of the adaxial and abaxial surfaces of A. donax leaf was performed herein in an attempt to track such chemophenetic adaptations. This sort of approach is of the utmost importance for the current debate about the hypothetical invasiveness of this species in the Mediterranean basin versus its natural colonization along the Plio-Pleistocene period. We concluded that the leaf surfaces contain, apart from stomata, prickles, and long, thin trichomes, and silicon-rich tetralobate phytolits. Chemically, the dominating elements in the leaf ashes are oxygen and potassium; minor amounts of calcium, silicon, magnesium, phosphorous, sulphur, and chlorine were also detected. In both surfaces the epicuticular waxes (whose density is higher in the adaxial surface than in the abaxial surface) form randomly orientated platelets, with irregular shape and variable size, and aggregated rodlets with variable diameter around the stomata. In the case of green mature leaves, the dominating organic compounds of the epicuticular waxes of both surfaces are triterpenoids. Both surfaces feature identical hydrophobic behaviour, and exhibit the same total transmittance, total reflectance, and absorption of incident light. The above findings suggest easy growth of the plant, remarkable epidermic robustness of the leaf, and control of water loss. These chemophenetic characteristics and human influence support a neolithization process of this species along the Mediterranean basin.

Investigation of hydrophobic and anti-corrosive behavior of Cr-DLC film on stainless steel bipolar plate

In order to improve the corrosion resistance and hydrophobic electrical resistivity of stainless steel bipolar plate (BPP) of polymer electrolyte membrane fuel cell (PEMFC), diamond-like carbon doped with Cr (Cr-DLC) films with different Cr content were fabricated on stainless steel 304 without transition layer via magnetron sputter. The surface morphology, structure, hydrophobic properties, electrical resistivity, and corrosion resistance of the samples were analyzed. As the power of the graphite target increased, the sp2C content and surface roughness of the films first decreased and then increased. The results showed that all the films increased the contact angle and improved the corrosion resistance of the substrates. Especially, the sample with Cr content of 2.58 at.% showed a relatively higher contact angle and better corrosion resistance in different solutions. It showed the lowest current density of 6.5 × 10−8 A/cm2 and 2.59 × 10−8 A/cm2 in 3.5 % NaCl solution and 0.1 M H2SO4 solution, respectively. Additionally, the corrosion potential of it was −0.5 mV in 0.1 M H2SO4 solution, which was much higher than the substrate. The excellent corrosion resistance of the sample with a Cr content of 2.58 at.% was attributed to the lower surface roughness, passivation of the Cr2O3 on its surface, and the inertness of CrxCy, which compensated for pinhole defects during the corrosion tests. The results convinced that Cr-DLC film exhibits excellent properties that can supply an option for stainless steel used as BPP.

Engineered polymer matrix novel biocompatible materials decorated with eucalyptus oil and zinc nitrate with superior mechanical and bone forming abilities

Electrospun scaffolds based on polymer-matrix composites have gained wide attention recently. A novel engineered biocompatible scaffold is manufactured using polyurethane (PU) loaded with eucalyptus oil (EL) and Zinc nitrate (ZnNO3) using the electrospinning technique. Morphological observations revealed the reduced fibre diameter for the PU/EL and PU/EL/ZnNO3 compared to PU. Contact angle studies indicated the increase in hydrophobic behaviour of the PU/EL whereas an increase in wettability for PU/EL/ZnNO3 compared to PU. EL and ZnNO3 presence in the PU matrix enhanced the mechanical strength. Surface topology analysis showed a decrease in the roughness for the PU/EL and PU/EL/ZnNO3 compared to the pristine PU. Both PU/EL and PU/EL/ZnNO3 showed prolonged clotting time and decreased haemolytic percentage compared to the polyurethane as indicated in their anticoagulation studies. In vitro bone mineralisation testing depicted the increase in calcium deposition for the modified PU samples compared to pure polyurethane sample. Hence, PU/EL and PU/EL/ZnNO3 scaffold with superior properties render full avenues for new bone generation.

Screen-Printed Microcantilevers Coated With Functionalized Mesocellular Foam Silica for Detection of Solvent Vapors

This work presents an application of mass-sensitive microcantilevers coated with a new alternative of sensitive materials that is hexamethyldisilazane functionalized mesocellular foam silica (HMDS-MCF-Si) for detection of solvent vapors. The microcantilevers (3 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times2$ </tex-math></inline-formula> mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times0.1$ </tex-math></inline-formula> mm) based on a lead zirconate titanate (PZT) beam sandwiched by thin gold (Au) electrodes were fabricated by screen-printing. Mesocellular foam silica (MCF-Si) was synthesized and used as the sensitive material due to its high specific surface area and pore volume. This material was functionalized by hexamethyldisilazane (HMDS) to enhance hydrophobicity. By a small deposition of HMDS-MCF-Si, the obtained devices demonstrated longitudinal vibration mode with the quality factor of approximately 200 at ambient temperatures. Responsiveness of the microcantilever coated with HMDS-MCF-Si to each solvent vapor at room temperature was compared. The largest response was obtained from exposure to toluene vapor with the sensitivity of 0.85 ppm/ppmV (218 mHz/ppmV) and a limit of detection (LOD) of 28 ppmV. The sensitivity dropped by almost six times when exposed to the higher polar vapor of ethanol. Very low response to water vapor (0.05 ppm/ppmV) confirmed the hydrophobic behavior of HMDS-MCF-Si. Detectable performances under different vapors of our device can be utilized as a guide for developing sensitive materials and resonant microcantilever-based vapor sensors.

Synthesis of Nano Ceramic Epoxy Hybrid Composite Coating on Metallic Substrate for Corrosion Protection

In this study, the corrosion protection behavior of fumed SiO2 reinforced epoxy composite coatings applied on steel substrates was evaluated and compared to graphene-epoxy nano-composite coatings. Graphene-epoxy nano-composite coatings provide excellent corrosion protection but the uniform dispersion of graphene in polymer solvent is a challenge. So, the fumed silica was chosen as the reinforcement rather than graphene. Fumed silica was treated with stearic acid and used with epoxy to get hydrophobic and corrosion resistant coatings. The partial carburization of epoxy was carried out to get carbon layer on steel substrate. The epoxy was cured at various temperatures (200, 250 and 300 °C) to see its effect on hydrophobicity and corrosion behavior of the composite coatings. Presence of different functional groups of modified silica and epoxy was confirmed by FTIR ATR. Coating prepared from this material was evaluated microscopically with respect to structure, uniformity and interface with optical microscope. Polarization effect of coatings was studied by potentiodynamic polarization method. Coating thickness was measured by an Elcometer gauge, and these were checked by the micrographs at 50, 200 and 1000x. E250 (60% epoxy + 6% Silica) showed corrosion rate of 0.017mpy much lower than uncoated steel substrate (2.612mpy). Contact angles for npc200 (neat partially carburized epoxy cured at 200°), 4Si70 (60% epoxy+4% Silica cured at 70°), 6Si300 (60% epoxy+6% Silica cured at 300°) and 6Si250 (60% epoxy+6% Silica cured at 250°) were 90°, 89.5°, 72.5° , 97.5° respectively. So, it was proved that partially carburized epoxy coating with 6% modified silica cured at 250 °C was more corrosion resistant and hydrophobic in nature.

Cardanol and bisphenol-F based benzoxazines with zirconium phosphate reinforced composites coating for protecting the mild steel surface from corrosion

The present work is to develop and characterize the benzoxazines from cardanol and bisphenol-F with imdazole core based amine in order to utilize them in the form of (50/50 wt%) blended composites coating for corrosion resistance application. The benzoxazine blends were reinforced with varying weight percentages of (0.5, 1, 1.5, 2.0 and 2.5 wt%) of 3-glycidoxypropyltrimethoxysilane (GPTMS) functionalized zirconium phosphate (ZrP) to obtain respective composites blended coatings. The thermal stability of composites was studied by thermogravimetric analysis (TGA). In order to ascertain their hydrophobic behavior the water contact angle studies were carried out and the values obtained for 0.5, 1, 1.5, 2.0 and 2.5 wt% GPTMS functionalized ZrP reinforced (50/50 wt% of C-ima/BF-ima) benzoxazines blended composites are 114,116,117,119,120 and 123° respectively. The UV shielding behavior of ZrP reinforced polybenzoxazine blended composites material was also studied by UV-Vis spectroscopic technique and the results obtained infer that these materials possess good UV shielding behavior. ZrP reinforced benzoxazine blended composites were coated on the mild steel specimens and their corrosion resisting behavior was studied. Results of Nyquist plot and Tafel plot, ascertain that among the coated specimens, the specimen coated with 2.5 wt% ZrP reinforced poly(C-ima/BF-ima) blended composites exhibits highest corrosion resisting efficiency.

Inspired by the Nature: A Post-printed Strategy to Efficiently Elaborate Parahydrophobic Surfaces

The lack of drinkable water is one of the most significant risks for the future of the humanity. Estimates show that in the near future, this risk will become the origin of massive migrations leading to humanitarian disaster. As consequence, the development of solutions to provide water is becoming ever more critical, and a significant effort is devoted to identifying new sources of water. Among the developed strategies, fog harvesting, which takes advantage of atmospheric water to provide potable water, is a solution of interest due to its potential in sustainable development. Unfortunately, this approach suffers from low yield. In the present work, we take inspiration from living species to design and elaborate surfaces with high potential for water harvesting applications. This work takes advantage of 3D-printing and post-printing functionalization to elaborate a strategy that allows modelling, printing, and functionalization of surfaces to yield parahydrophobic behavior. The roughness and surface morphology of the prepared surfaces were investigated. These characteristics were then related to the observed wettability and potential of the functionalized interfaces for water harvesting applications. This work highlights significant variations in surface wettability via surface modification; strong hydrophobic behavior was observed via modification with linear carboxylic acids particularly for surfaces bearing vertical blades (plate with vertical blades and grid with vertical blades).

Development of Eco-Friendly Hydrophobic and Fouling-Release Coatings for Blue-Growth Environmental Applications: Synthesis, Mechanical Characterization and Biological Activity.

The need to ensure adequate antifouling protection of the hull in the naval sector led to the development of real painting cycles, which involve the spreading of three layers of polymeric material on the hull surface exposed to the marine environment, specifically defined as primer, tie coat and final topcoat. It is already well known that coatings based on suitable silanes provide an efficient and non-toxic approach for the hydrophobic and antifouling/fouling release treatment of surfaces. In the present work, functional hydrophobic hybrid silica-based coatings (topcoats) were developed by using sol-gel technology and deposited on surfaces with the “doctor blade” method. In particular, those organic silanes, featuring opportune functional groups such as long (either fluorinated) alkyl chains, have a notable influence on surface wettability as showed in this study. Furthermore, the hydrophobic behavior of this functionalized coating was improved by introducing an intermediate commercial tie-coat layer between the primer and the topcoat, in order to decrease the wettability (i.e., decreasing the surface energy with a matching increase in the contact angle, CA) and to therefore make such coatings ideal for the design and development of fouling release paints. The hereby synthesized coatings were characterized by optical microscopy, contact angle analysis and a mechanical pull-off test to measure the adhesive power of the coating against a metal substrate typically used in the nautical sector. Analysis to evaluate the bacterial adhesion and the formation of microbial biofilm were related in laboratory and simulation (microcosm) scales, and assessed by SEM analysis.

O-carboxymethyl chitosan/gelatin/silver-copper hydroxyapatite composite films with enhanced antibacterial and wound healing properties.

Wound dressing composite films of O-carboxymethyl chitosan (OCMC) and gelatin were prepared and mixed with hydroxyapatite (HA) composited with Silver (Ag) and Copper (Cu) at different concentrations. The chemical, thermal, morphological, and biological properties of the composite films were studied. The analysis by FTIR confirmed the presence of interactions between gelatin and OCMC, and at the same time, the polymer matrix interactions with Ag-Cu/HA complex. The inclusion of nanoparticle to the composite was associated with an improvement of the thermal stability, morphological roughness, a 9-12% more hydrophobic behavior (composite C1, C5, and C8), increase in antibacterial activity from 23.2 to 33.1% for gram negative bacteria and from 37.28 to 40.59% for gram positive bacteria, and with a cell viability greater than 100% for 24 and 72h. The films obtained can serve as a wound healing dressing and regenerating biomaterial.

Biomimetic Rose Petal Structures Obtained Using UV-Nanoimprint Lithography.

This study aims to produce a hydrophobic polymer film by mimicking the hierarchical micro/nanostructures found on the surface of rose petals. A simple and two-step UV-based nanoimprint lithography was used to copy rose petal structures on the surface of a polyurethane acrylate (PUA) film. In the first step, the rose petal was used as a template, and its negative replica was fabricated on a commercial UV-curable polymer film. Following this, the negative replica was used as a stamp to produce rose petal mimetic structures on UV curable PUA film. The presence of these structures on PUA influenced the wettability behavior of PUA. Introducing the rose petal mimetic structures led the inherently hydrophilic material to display highly hydrophobic behavior. The neat PUA film showed a contact angle of 65°, while the PUA film with rose petal mimetic structures showed a contact angle of 138°. Similar to natural materials, PUA with rose petal mimetic structures also displayed the water pinning effect. The water droplet was shown to have adhered to the surface of PUA even when the surface was turned upside down.

Synthesis and characterization of engineered PEEK‐based composites for enhanced tribological and mechanical performance

AbstractWe report the synthesis and characterization of engineered PEEK‐based composites by using biochar (DDGS500—pyrolyzed Distiller's dried grains with soluble (DDGS)), metal (Mo), and PEEK‐ceramic (Xonotlite) as reinforcements. A systematic study was done to understand the effect of these additives on functional and mechanical properties. Initially, these composites were synthesized by hot pressing. Microstructure analysis of reinforcement powders by scanning electron microscopy (SEM). Detailed microstructure study of the composites showed that DDGS500 powder particulates were well dispersed within the PEEK matrix after the addition of 5 vol%. However, at higher concentration of 10 and 20 vol%, the particles segregated at the phase boundaries and PEEK rich cores were observed in the microstructure. Mo and Xonotlite particles were segregated at the phase boundaries even at 5 vol% concentration, which was more prominent at higher concentrations of 10 and 20 vol% reinforcements. Differential scanning calorimetry (DSC) showed lowering in melting point (Tm) and crystallization temperature (Tc) and increase in crystallization in all the composites. The addition of DDGS500 and Mo enhanced the plasticity and Ultimate Compressive Strength (UCS) (5 vol% additions of DDGS500 and Mo enhanced the UCS by 12.6% and 32.2%, respectively) of the composites whereas Xonotlite additions increased brittleness of the composites. The addition of DDGS500, PEEK‐Mo, and PEEK‐Xonotlite particulates lowered the wear rate until 10 vol% by several orders of magnitude and stabilized the friction coefficient (μ) versus distance profile. However, significant increase in wear rate at 20 vol% of Xonotlite was observed due to third body abrasion. All the composites showed hydrophobic behavior except PEEK‐20 vol% Xonotlite, which showed hydrophilic behavior with a decrease in contact angle as a function of time, which shows that Xonotlite can be a promising additive for increasing hydrophilicity of PEEK‐based composites for biomedical applications.

Hydrophobic and oleophilic 3D weft-knitted spacer fabrics coated by silica aerogels with five different concentrations

Silica aerogels were made from tetraethylorthosilicate by the sol-gel method and coated on the 3D weft-knitted spacer fabrics (WKSFs) to compare the interaction of the silica aerogel coating with five various concentrations. SEM, FTIR-ATR, surface roughness, surface energy, and BET analysis were used to observe and characterize the surface morphology, molecular interaction, surface changes, surface tension, and specific surface area of fabric samples or sorbents. Consequently, this study investigated the wettability, oil absorption capacity, oil retention capacity, and reusability of untreated and treated 3D WKSF sorbents. The outcomes exposed the excellent hydrophobic and oleophilic properties of all treated 3D WKSF sorbents, showing a greater water contact angle of 145.1 ± 0.42°, and an oil absorption and retention capacity of (7.87 ± 0.09 g/g and 7.53 ± 0.06 g/g) and (89.98 ± 0.79% and 92.48 ± 0.56%) for vegetable oil and engine oil, respectively, with notable reusability, most particularly for sorbent 5, due to the higher silica aerogel add-on %, pore diameter, and pore volume. The findings verified that the chemical composition and fabric structure played an important role in the tremendous hydrophobic and oleophilic behavior. The statistical study on specific surface area, pore diameter, pore volume, surface roughness, water contact angle, oil contact angle, oil absorption capacity, and oil retention capacity also revealed that treated fabrics performed significantly ( p &lt; 0.05) in hydrophobic and oleophilic features at the 0.05 level. Hence, these fabrics can be used in industrial usages that need hydrophobic and oleophilic qualities.

Nanocellulose for Paper and Textile Coating: The Importance of Surface Chemistry.

Nanocellulose has received enormous scientific interest for its abundance, easy manufacturing, biodegradability, and low cost. Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) are ideal candidates to replace plastic coating in the textile and paper industry. Thanks to their capacity to form an interconnected network kept together by hydrogen bonds, nanocelluloses perform an unprecedented strengthening action towards cellulose- and other fiber-based materials. Furthermore, nanocellulose use implies greener application procedures, such as deposition from water. The surface chemistry of nanocellulose plays a pivotal role in influencing the performance of the coating: tailored surface functionalization can introduce several properties, such as gas or grease barrier, hydrophobicity, antibacterial and anti-UV behavior. This review summarizes recent achievements in the use of nanocellulose for paper and textile coating, evidencing critical aspects of coating performances related to deposition technique, nanocellulose morphology, and surface functionalization. Furthermore, beyond focusing on the aspects strictly related to large-scale coating applications for paper and textile industries, this review includes recent achievements in the use of nanocellulose coating for the safeguarding of Cultural Heritage, an extremely noble and interesting emerging application of nanocellulose, focusing on consolidation of historical paper and archaeological textile. Finally, nanocellulose use in electronic devices as an electrode modifier is highlighted.

Effect of palmyra sprout fiber and biosilica on mechanical, wear, thermal and hydrophobic behavior of epoxy resin composite

In this study, natural fiber epoxy composites were prepared using palmyra sprout fiber and red matta rice husk ash(RHA) biosilica. This paper mainly aims to investigate the mechanical, wear resistance, thermal stability as well as water absorption behaviour of naturally obtained novel fiber with red matta biosilica in epoxy based composites. The fiber’s surface was treated by base, while the biosilica particles were treated by amino-silane. The composites were fabricated by hand lay-up process and characterized based on ASTM standards. According to the results the highest tensile and flexural strength observed for the composite is about 147 MPa and 211 MPa for 3 vol. % of biosilica with 30 vol. % of fiber. Izod impact toughness reveals the maximum impact resistance up to 5.82 J. Increment in reinforcement vol. % shows increased hardness. Wear properties represents the composite designations EPB3 retains good wear resistances for 3 vol. % of biosilica. Similarly, thermal stability improved by the addition of biosilica of 3 vol. %. Water absorption results reveal that, the addition of reinforcements marginally affects the contact angle. Such mechanically improved, wear resistible and thermally stable natural composites could be used in automotives, industrial and defense applications as well as in household appliances.