Surface Modification Process Research Articles

Microstructures, optical, magnetic properties, and specific absorption rate of novel magnetite/mesoporous silica nanoparticles synthesized using green route for magnetic hyperthermia application

In this study, novel magnetite (Fe3O4)/mesoporous silica nanoparticles (MSN) were prepared by the green synthesis method using Moringa oleifera extract with various MSN concentrations. The crystallite size of Fe3O4/MSN decreased from 10.5 to 9.0 nm with the increase of MSN concentrations. However, as shown from transmission electron microscope images, the surface modification process increases its particle size from 10.7 ± 0.1–27.8 ± 0.3 nm. Scanning electron microscopy images revealed that MSN has a porous structure, and the shape of Fe3O4/MSN was nearly spherical. The Fourier transform infrared spectra showed the functional group of Si-O-Si at 1041 cm−1, indicating a successful surface modification process. After modification using MSN, the band gap energy of the nanoparticles decreased from 3.61 to 3.27 eV. The magnetic properties analysis showed that the saturation magnetization of Fe3O4 and Fe3O4/MSN was 55.32 ± 0.03 emu/g and 53.45 ± 0.04 emu/g, respectively. In contrast, the coercivity increased from 57.7 ± 0.3–149.5 ± 0.5 Oe. Additionally, the specific absorption rate (SAR) of Fe3O4/MSN to evaluate its potential for magnetic hyperthermia applications were investigated. The highest SAR values of Fe3O4 and Fe3O4/MSN were 91.8 mW/g and 86.7 mW/g, which decreased with increasing MSN concentrations. Furthermore, these results proved that the green-synthesized Fe3O4/MSN was a promising candidate and potentially optimized the performance of future magnetic hyperthermia applications.

SiC nanofiber-reinforced Ag matrix composites exhibiting high strength and ductility

In this work, we demonstrated an example of leveraging the intrinsic morphology features of one-dimensional SiC nanofiber (SiCnf) to design high-performance Ag-metal matrix composites (MMCs) using powder metallurgy techniques. To break up the SiCnf agglomerates and increase surface functionality while maintaining its integrity, the raw SiCnf underwent a specially developed surface modification process. Following a combination of hetero-agglomeration, spark plasma sintering and hot extrusion, the SiCnf was homogeneously dispersed and singly aligned throughout the Ag matrix. Microstructure observations revealed close contact between the SiCnf and the Ag matrix, resulting in a sawtooth-like SiCnf-Ag interface induced by the plastic flow of Ag. Thanks to the presence of strong mechanical anchors at SiCnf protrusions, the load transfer efficiency of the SiCnf-Ag interface reached 72 %. Consequently, the SiCnf/Ag composite exhibited a high tensile strength of 219 MPa and a substantial failure elongation of 39.2 %. This work underscores the importance of optimizing interfacial microstructures and offers the new insights of designing novel Ag-MMCs for applications in conductive devices.

Surface modification and patterning of polymer thin films by plasma and adsorption behavior of proteins

The surface wettability property of hydrophobic polystyrene (PS) and hydrophilic polyethylene glycol (PEG) thin films subjected to modification by direct current plasma glow discharge is studied. The polymer films exhibited change of surface wettability on exposure to air, nitrogen, oxygen or argon plasmas. In PS films a swift modification to hydrophilic surface and subsequent steady recovery following first order kinetics are observed. The rate of modification and recovery are adjustable by adjusting the plasma ambient and parameters and additional wet-chemical treatment using ionic solutions. In PEG films the hydrophobic wettability evolve with ageing following the first order kinetics, and is stable for long period on exposure to air ambient. Moreover, a vapor deposition like process is possible using the PEG films as source to deposit self-assembled molecular layers with hydrophobic wettability on other surfaces. Using these surface modification or molecular deposition processes, the fabrication of wettability patterns in the surface of PS and PEG films and on other surfaces by vapor transport using PEG films, and also the possibility to produce gradient wettability patterns are demonstrated. Moreover, the adsorption behavior of immuno-specific system of proteins on surface modified hydrophilic PS films is studied.

Surface treatment optimization of mixed cellulose ester membrane by cold plasma treatment to improve apple juice clarification

This study aimed to determine the optimal conditions for the surface modification of mixed cellulose ester (MCE) microfiltration membrane by cold plasma (CP) for apple juice clarification. Response surface method using central cubic design (CCD) was employed for the optimization of the membrane surface modification process. Plasma gas type (oxygen, carbon dioxide, and air), power (10, 15, and 20 W), and exposure time (120, 180, and 240 s) were used as the factors for cold plasma surface modification. The results revealed the surface modification of the MCE membrane using air as plasma gas with plasma power and exposure time equal to 10 W and 180 s resulted in the maximum permeate flux in apple juice clarification. The results of scanning electron microscope, and atomic force microscope confirm the effect of CP treatment on the membrane surface roughness. Fourier transform infrared spectroscopy showed the incorporation of the hydroxyl group into the membrane surface due to CP treatment which affected the surface contact angle and hydrophilicity. The CP treatment of the membrane significantly affects the membrane resistances. Also, the surface modification of the MCE membrane using the CP treatment process in optimal conditions is an effective method for clarifying apple juice.

Surface treatment of metal by combined particle beam

This work is related to modeling of metal surface modification process by combined particles beam. On the basis of thermodynamics of irreversible processes, including equations of state in differential form, a nonlinear model is formulated. The model takes into account the interaction of thermal, diffusion and mechanical waves and finiteness of relaxation times of thermal and diffusion processes. For the combined particle flow such model is proposed for the first time. The numerical algorithm is based on implicit difference schemes. The study of the interaction of waves of different nature is carried out on the example of a copper target treated with nickel and gold particles. It is shown that deformations take the maximal value at the left boundary, which is directly related to the presence of impurity concentration gradients. Depending on the pulse duration, the difference between the extrema on the elastic wave becomes less significant. With increasing temperature, obviously, the diffusion process accelerates. The propagation velocities of the interacting waves are different. The character of distributions of concentrations of introduced particles directly depends on the value of parameters proportional to relaxation times.

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.

One-pot fabrication of hydrophobic, superelastic, harakeke-derived nanocellulose aerogels with excellent shape recovery for oil adsorption and water-in-oil emulsion separation

Cellulose-based aerogels have attracted significant attention for oil/water separation due to their high porosity, large specific surface area and high adsorption capacity. However, their intrinsic hydrophilicity, and inadequate mechanical properties have often limited their practical applications. Traditional freeze-dried cellulose aerogels exhibit unsatisfactory elasticity and require a separate surface modification process to adjust the surface wettability. In this study, we present a novel one-pot fabrication strategy which simultaneously achieves the crosslinking of individual cellulose nanofibers and the hydrophobic modification of the surface wettability. Following directional freeze-drying, hydrophobic, superelastic, and anisotropic cellulose-based aerogel was prepared from the 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO)-oxidized cellulose nanofibers, isolated from harakeke (New Zealand native flax). The resulting aerogel exhibits a high water contact angle of 142°, good compressive recovery performance (85 % recovery of the original height after 100 compression cycles at 70 % strain), and outstanding adsorption capacity for various types of oil and organic solvents (80–105 g/g). Furthermore, the aerogel could also be used as a filter to separate surfactant stabilized water-in-oil emulsions with a high flux (782 L m−2 h−1) and a high separation efficiency (98.7–99.2 %). The novel aerogel prepared in this study is expected to have great potential for practical applications in oily wastewater remediation.

A Novel, Selective, and Fast Electrochemical Sensor Based on an 8-Nitroquinoline-Coated Pencil Graphite Electrode for Rutin Determination in Orange Juice

In this study, we developed a facile and low-cost method to prepare a modified electrode by coating the pencil graphite electrode (PGE) surface with 8-nitroquinoline (8-NQ). The surface modification process was carried out by electrochemical reduction of 8-NQ on the PGE surface in ethanol solution. The optimum conditions were determined for the experimental studies. The differential pulse voltammetry was used to determine rutin with the modified electrode (8-NQ/PGE). The developed electrode showed excellent performance for rutin oxidation in a pH 3.0 Britton Robinson buffer (BR). In this media, linearly increasing anodic peak currents were observed with the concentration of rutin in two wide concentration ranges (i.e., 0.016–0.96 μM and 0.96‒19.73 μM), the sensor showed a low detection limit (i.e., 4.14 nM) (3 s m−1). It displayed good stability and selectivity. Also, it was used successfully for the determination of rutin in orange juice samples.

A green bulk modification for imparting a green VIPS membrane with antifouling properties

BackgroundMembrane preparation and membrane modification processes have long involved the use of toxic solvents. The present work proposes to only use envrionmentally-friendly solvents for both the fabrication and the surface modification of hydrophobic microfiltration membranes. In addition, coating processes for membrane modification are essentially surface modification processes. However, spray-coating may be a suitable method for both surface and bulk modification. MethodsAfter dissolving poly(vinylidene fluoride) in dimethylsulfoxide, membranes were formed by the vapor-induced phase separation process, and then modified using an aqeous solution of an amphiphilic copolymer containing poly(ethylene glycol) methyl ether methacrylate units. Then, a variety of physicochemical techniques were employed to characterize the membrane structure and prove the effectiveness of the surface/bulk modification. Antifouling tests in static and dynamic conditions were conducted. Significant findingsIt is possible to reduce the water contact angle of the top surface of the membrane from 135° to 0° and that of the bottom surface from 126° to 0° within <10 s, indicating successful hydrophilization of the membrane on the one hand, and top-to-bottom modification, despite solely exposing the top surface to the spray, on the other hand. This conclusion was confirmed by deidcated surface chemistry analyses. Besides, the membranes maintained their original highly porous and symmetric structure with light effects on surface porosity and pore size following the spray-coating process. The drasting improvement of hydrophilicity resulted in effective mitigation of fibrinogen adsorption (reduced by 85 %) and Escherichia coli adhesion (reduced by 86 %). Fouling during cyclic filtration involving a bacterial suspension was also effectively reduced with a flux recovery ratio of 53 % (against 37 % for a commercial hydrophilic membrane) and an irreversible flux decline ratio of 47 % (against 63 % for a commercial hydrophilic membrane) in the conditions of the test.

A parametric study on chemical activator selection and soaking procedure development for barium incorporation in concurrent activated and surface modified palm kernel shell derived activated carbon

The concurrent activation and surface modification (CAM) process is an integrated process used to synthesise palm kernel shell derived activated carbon (PKSdAC) in this study. CAM involves chemical activation and surface modification via metal impregnation in one process. This study investigated the usage of different acids as chemical activators and different soaking procedures for impregnating barium (Ba) in CAM-PKSdAC. It shows that chemical impregnation of PKS using 10% sulphuric acid (H2SO4) mass loading via two soaking steps can impregnate a high Ba amount of 0.86–2.98 wt. % in CAM-PKSdAC, compared to one soaking step. The two soaking steps procedure reduced the overage formation of BaSO4 from sealing the pores of PKS. Comparing HCl and H2SO4, at 30% acid mass loading, the impregnation of PKS with H2SO4 produced a higher impregnated Ba amount in CAM-PKSdAC. BaSO4 generated from the reaction between H2SO4 on the PKS surface with BaCl2 solution causes a reduction reaction at high temperatures. BaSO4 reacted with a carbon-reducing agent and is reduced to barium sulphide (BaS), impregnating Ba on CAM-PKSdAC. In conclusion, H2SO4 was found to be the suitable chemical activator with two soaking steps for the CAM process.

Investigation into the role of Si and SiC phases in RB-SiC ceramics surface modified ultra-precision grinding

RB-SiC ceramic has greater specific stiffness and thermal stability as space optical materials in the field of deep space exploration. To ultra-precision grinding advanced manufacturing technology drawbacks, a fabrication of highly shape accuracy and surface quality and surface modification assisted processing at room temperature. The RB-SiC ceramics are modified by plasma torches to produce compounds with lower hardness values, an exceptional surface quality (Sa surface roughness of [0.481, 0.959]), and has excellent thermal and chemical stability after surface modification process via 100 °C plasma torch at room temperature environment, which makes it an ideal suitable for the deep space exploration conditions such as space optical materials. In addition, oxygen(O2) plasma surface modification and finite element simulation force-heat conduction of RB-SiC ceramic hard-brittle materials surface grinding force were compared with advanced manufacturing experiments of the precision grinding, revealing the formation mechanism and influence mechanism of surface micro-morphology during micro-cutting of precision grinding finish surface. The advanced manufacturing precision grinding difficulties of RB-SiC ceramic oxygen plasma torch reducing subsurface damage and removing space optical hard-brittle materials via ultra-precision grinding process of resin-funded corundum grinding wheel were solved. Subsurface damage (SSD) was effectively inhibited and its formation mechanism model.

Plasma/Ozone Induced PolyNaSS Graft-Polymerization onto PEEK Biomaterial for Bio-integrated Orthopedic Implants

Owing to its superior bulk mechanical properties, poly (ether ether ketone) (PEEK) has gained popularity over the past 15 years as a metal substitute in biomedical implants. Low surface energy is a fundamental issue with PEEK implants. This low surface energy caused by a moderately hydrophobic surface may be able to inhibit cellular adherence and result in the development of an inflammatory response, which may result in cell necrosis and apoptosis. In this work, plasma and ozone treatments have been utilized to surface activate PEEK and graft ionic bioactive polymer polyNaSS (poly (sodium styrene sulfonate)) successfully on the surface to promote cellular attachment and biomineralization. The main goal of our research has been to find a stable green process for surface modification of PEEK by plasma/ozone approaches to increase PolyNaSS grafting efficiency and biomineralization. To further the field of bioactive orthopedic and dental implant technology, this research attempts to address a significant constraint of PEEK implants while preserving their favorable mechanical properties.

Surface modification for steel rods based on atmospheric-pressure nitrogen plasma treatment at room temperature

A surface modification process for steel rods based on atmospheric-pressure nitrogen plasma (APP) at room temperature was developed. Steel rods were irradiated with APP generated by dielectric-barrier discharge in a nitrogen atmosphere. Elemental analysis using an electron-probe microanalyzer revealed strong nitrogen signals at the top surface, which suggests the formation of a modified layer due to the generation of excited nitrogen sources by APP. However, no noticeable nitrogen diffusion into the steel was observed. This is because the excited nitrogen sources reacted with elemental iron emitted by APP and nitrides were deposited on the surface of the steel. The proposed APP treatment is a promising approach for modifying the surface of steel rods without heat treatment.

Encapsulating Fe3O4 Nanoparticles and Carbon Dots in a Metal-Organic Framework for Magnetic Fluorescent Taggants.

Magnetic fluorescent composite nanomaterials have broad application prospects in the fields of biological imaging, anticounterfeiting identification, suspicious object tracking, and identification of latent fingerprints in forensic medicine. For an effective taggant, a clearly visible identifying mark is necessary to enable observers to capture labeling information quickly and accurately, even from a distance. The preparation method of magnetic fluorescent composite materials is complicated and usually needs different surface modification and assembly processes. The limited loading capacity of fluorescent materials also limits the fluorescence properties of the composite, so it is difficult to produce obvious fluorescence as a taggant to meet the requirements of visible labeling. In this study, a core-shell structure of a magnetic fluorescent composite was prepared by using the metal-organic framework ZIF-8 as the host of fluorescent materials and an encapsulation shell coated on the Fe3O4 nanoparticles. The porous ZIF-8 is beneficial for increasing the loading capacity of fluorescent materials to ensure the fluorescence performance of the composite materials. Further modification of the composite surface prevented the desorption of fluorescent materials from the pores of ZIF-8, enabling the samples to maintain good fluorescence properties even after multiple washing cycles. The preparation method is simple, rapid, and cost-effective, and the prepared magnetic fluorescent composite nanomaterial has high magnetic separation performance and fluorescence performance, making it a promising material for identification, marking, and tracking.

Dry media reaction-based anti-hydration coating on magnesium oxide microspheres for thermal interfacial applications

Magnesium oxide (MgO) is gaining attention as a next-generation thermal management material due to its better thermal conductivity compared to other oxides and excellent insulating properties. However, its susceptibility to hydration when exposed to atmosphere, which alters its material properties, necessitates the application of anti-hydration coatings for its use in thermal management. This study explores the use of Chemical Vapor Deposition (CVD) and Plasma-Enhanced Chemical Vapor Deposition (PECVD) as alternatives to the traditional sol–gel method to form anti-hydration coatings on MgO microspheres. The surface modification process was completed within 20 min for both processes, and the water contact angles of the spheres increased from ∼33° to ∼98° with CVD and ∼125° with PECVD. Compared to CVD, PECVD was found to be more effective in applying anti-hydration coatings, thanks to the plasma activation of the MgO surface and reactants, thereby better maintaining the physical and chemical properties under conditions of 85 °C and 85 % relative humidity. Furthermore, when used as a filler in thermal interface material composites, MgO modified with PECVD exhibited adhesion strength and thermal conductivity about 1.5 times higher than bare MgO, due to the increased affinity for the hydrophobic binder.

Plasma-modified viscose rayon activated carbon felt (VR-ACF) for Cu(II) and Cd(II) decontamination-mechanism and continuous-flow column operation

This study investigates the enhanced removal of Cu(II) and Cd(II) heavy metal ions from water using viscose rayon based activated carbon felt (VR-ACF). Employing a synergistic approach involving oxidant (KMnO4) and plasma treatment, the surface modification process was meticulously examined. Key findings demonstrate the superior efficacy of KMnO4 over H2O2 and Na2S2O8 in coating. The synergy between plasma modification and 0.1 M KMnO4 enhances VR-ACF’s adsorption capacity, ensuring effective metal ion removal. Fine-tuning plasma parameters aids a comprehensive understanding of the modification process, guiding successful metal ion removal. Adsorption complexities are evidenced by prolonged kinetics of 720 min at pH 5 with high Qmax of 175.43 mg/g for Cu(II) and 223.22 mg/g for Cd(II), and extended column experiments, affirming the efficacy of modified VR-ACF. Thermodynamic analyses underscore the spontaneity and variability of Cu(II) and Cd(II) adsorption. X-ray photoemission spectroscopy (XPS), Scanning electron microscopy (SEM), X-ray Diffraction (XRD) investigations endorse complexation, ion-exchange, co-precipitation, and solvation interactions. Recyclability tests reveal maintenance of 60% removal efficiency for five cycles, with reduced efficiency in the presence of phosphates and divalent cations. The 50% breakthrough time for adsorption of Cu(II) and Cd(II) was found to be 58 days and 62 days, respectively. This underscores the efficacy of modified VR-ACF in sustainable water purification, particularly in extended column setups, offering a hopeful path for advanced materials in eliminating heavy metal ions.

Production of nanocomposite films based on low density polyethylene/surface activated nanoperlite for modified atmosphere packaging applications

The modified atmosphere packaging films based on polyethylene nanocomposites reinforced with perlite nanoparticles were prepared using a blow molding machine. The perlite particles were first reduced to nano dimensions using an abrasive mill, then the porosity of nanoperlite was increased to improve their efficiency in absorbing ethylene gas. For this purpose, 6 normal sodium hydroxide solution at 50°C temperature was used. Finally, perlite nanoparticles were modified by polymethyl hydrogen siloxane silane compound. In each of the stages of grinding and modifying the perlite surface, the necessary tests including dynamic light diffraction test, nitrogen absorption test and ethylene gas absorption test were performed using gas chromatography method. The results showed that the size of perlite particles was reduced to 500 nm by using an abrasive mill, and the surface modification process increased the specific surface area of perlite by 10 times. Based on this, the amount of ethylene gas absorption in perlite nanoparticles with modified surface increased up to 3 times compared to normal perlite. The results of the gas chromatography test showed that the nanocomposite film based on polyethylene reinforced with 6% by weight of modified perlite nanoparticles has several times the efficiency in absorbing ethylene gas compared to the potassium permanganate sachets The results of the mechanical properties tests of nanocomposite film in comparison with pure polyethylene film showed that nanocomposite film has higher properties than pure polyethylene. The results of shelf-life tests of green tomatoes packed in nanocomposite film based on polyethylene reinforced with modified nanoperlite showed that green tomatoes can be stored for two months using the prepared modified atmosphere packaging.

Successful application of photocatalytic recycled TiO2-GO membranes for the removal of trace organic compounds from tertiary effluent

Photocatalytic membranes are a promising technology for water and wastewater treatment. Towards circular economy, extending the lifetime of reverse osmosis (RO) membranes for as long as possible is extremely important, due to the great amount of RO modules discarded every year around the world. Therefore, in the present study, photocatalytic membranes made of recycled post-lifespan RO membrane (polyamide thin-film composite), TiO2 nanoparticles and graphene oxide are used in the treatment tertiary-treated domestic wastewater to remove trace organic compounds (TrOCs). The inclusion of dopamine throughout the surface modification process enhanced the stability of the membranes to be used as long as 10 months of operation. We investigated TrOCs removal by the membrane itself and in combination with UV-C and visible light by LED. The best results were obtained with integrated membrane UV-C system at pH 9, with considerable reductions of diclofenac (92%) and antipyrine (87%). Changes in effluent pH demonstrated an improvement in the attenuation of TrOCs concentration at higher pHs. By modifying membranes with nanocomposites, an increase in membrane hydrophilicity (4° contact angle reduction) was demonstrated. The effect of the lamp position on the light fluence that reaches the membrane was assessed, and greater values were found in the middle of the membrane, providing parameters for process optimization (0.29 ± 0.10 mW cm−2 at the center of the membrane and 0.07 ± 0.03 mW cm−2 at the right and left extremities). Photocatalytic recycled TiO2-GO membranes have shown great performance to remove TrOCs and extend membrane lifespan, as sustainable technology to treat wastewater.

Wool fiber as an In situ reducing agent towards ZnO-based surface modified fabric development: Durability assessment in the realm of textile applications

The development of a bio-inspired method to fabricate ZnO nanostructure-modified functional wool fabric represents a substantial challenge in the textile field. This article reports for the first time the use of wool as a reducing agent for the synthesis of ZnO nanoparticles. While previous studies have employed alternative natural reducing agents for surface modification of host materials, this investigation uniquely utilizes the host material, wool, as the reducing agent for in-situ ZnO nanoparticle synthesis. In addition to demonstrating the use of wool as a reducing agent, this literature uniquely reports the durability of the modified fabric, achieved through the use of trimethoxy methyl silane. This silane compound acts as a bridging agent, forming a strong interface between the wool fibers and the synthesized ZnO nanoparticles. This innovative approach enhances the adhesion and stability of the ZnO nanoparticles on the wool fabric, a key aspect that contributes to the overall durability and performance of the modified material. The in situ surface modification process employed a metal oxide precursor (zinc acetate dihydrate), capping agents (hexamethylene tetraamine, sodium carbonate, and sodium sulfate), and a coupling agent (trimethyl methoxy silane). The capping agents were used to control the reaction conditions, while the coupling agent was employed to improve the durability of the surface modification. The impact of three different capping agents on the corresponding synthesis process was assessed, and the findings revealed that the choice of capping agent helped to form ZnO nanoparticles with distinct morphologies. Analytical techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, were utilized to characterize the synthesized particles and the treated fabric. The XRD analysis coupled with SEM analysis confirmed the successful formation of ZnO nanoparticles. The ATR-FTIR spectroscopy provided evidence of the formation of Si-O-Zn and Si-O-C bonds, observed at around 920 cm−1 and 1040 cm−1 respectively. These spectroscopic findings indicate that the surface modification involving the silane compound has enhanced the durability of the ZnO-modified fabric. The covalent linkages between the ZnO nanoparticles, the silane compound, and the wool fibers, confirmed by SEM analysis before and after washing cycles, have enabled the durable attachment of the nanoparticles to the fabric surface, even after multiple washing cycles. The results suggest a novel pathway to use wool as a reducing agent for the surface modification of the same material. Detailed mechanistic insights into the surface modification process and the corresponding chemical interactions were also discussed.

Surface-engineered in-situ fibrillated thermoplastic polyurethane as toughening reinforcement for geopolymer-based mortar

Geopolymer composites often exhibit severe brittle failure when subjected to tensile and flexural loads, mainly owing to their inherently ceramic-like structure. Therefore, this study aims to overcome the previously mentioned weaknesses by introducing 2 wt% of surface-modified, in-situ fibrillated Co-PP (copolymer of polyethylene (PE) and polypropylene (PP))/thermoplastic polyurethane (TPU) blend to produce fiber-reinforced geopolymer mortars. The fiber-in-fiber Co-PP/TPU was first fabricated using spunbond, then functionalized using a mild, two-step, one-pot chemical surface modification process. A comprehensive and detailed study of the fibers' chemical structure, morphology, and mechanical properties has been conducted. As well as their impact on the geopolymer mortars' mechanical performances. Moreover, incorporating the modified fibers dramatically increased the flexural toughness and strength at failure of the composite, reaching up to 1600 % and 280 % compared to the control sample, respectively. Furthermore, the flexural modulus was improved by 2 folds. Additionally, the split tensile and compressive strength were improved by 84 % and 17 %, respectively. These findings and the SEM images of the fractured samples indicate the presence of several toughening mechanisms, associated with an improved matrix-fiber interface and an enhanced growth of geopolymer products around the fiber's surface.