And 3-aminopropyltriethoxysilane Research Articles

Exploring the potential of amine-functionalized mesoporous silica nanocarrier to conjugate guide RNA for gene delivery

Sugarcane is a key cash crop, with nations such as Brazil, India, and China being the leading producers. The trade of sugar and related products contributes significantly to these economies. Sugarcane is the primary feedstock for producing sugar and ethanol in the sugarcane processing industry, yielding sugarcane bagasse fly ash (SBFA) as a byproduct. This byproduct comes primarily from the combustion of bagasse (the fibrous residue after juice extraction) and contains silica (SiO2), alumina (Al2O3), and other minerals. The use of sugarcane waste materials reduces the need for new raw resources and lowers the environmental impact. Turning waste into valuable nanoparticles also helps manage waste better and reduces the amount that is burnt or dumped in landfills. The fly ash was treated with an alkaline solution (e.g., sodium hydroxide) to extract silica. This process helps dissolve other minerals, leaving a silica-rich residue. After extraction, the silica was purified through acid washing to remove impurities. Mesoporous silica nanoparticles were created using the sol-gel method and 3-aminopropyltriethoxysilane (APTES) was added to them functionally to conjugate sgRNA. The synthesized mesoporous silica nanoparticles were characterized for size and shape, functional groups, and crystallinity using various instruments such as Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering, Brunauer-Emmett-Teller (BET) Analyzer, and X-Ray Diffractometer (XRD), respectively. Furthermore, synthesized mesoporous silica nanoparticles were bioconjugated with sgRNA of OsEPF1, a gene negative regulation of stomatal development, which in turn, helps reduce yield loss in rice due to drought and heat stress.

Phase Change Materials for Energy Storage Applications from PEG and PBAT with AlN and CNT as Fillers.

This study investigates the fabrication of phase change material-poly(butylene adipate-co-terephthalate) (PCM-PBAT) composites through melt blending techniques, focusing on the impact of isophorone diisocyanate (IPDI) treatment on carbon nanotubes (CNTs) and (3-aminopropyl)triethoxysilane (APTES) treatment on aluminum nitride (AlN) particles. Analysis of mechanical properties highlights an enhancement in tensile strength with APTES-treated AlN particles, while dynamic mechanical analysis (DMA) reveals an increase in stiffness. Laser flash analysis (LFA) investigation demonstrates a significant increase, up to 325%, in thermal conductivity compared to PCM-PBAT composites without filler. Moreover, the fabricated composites exhibit enhanced latent heat storage capabilities, with the PCM-PBAT composite containing 30% filler (20PCM-PBAT-30F) showing promising latent heat values. These findings underscore the efficacy of selecting an appropriate PCM-PBAT ratio and surface functionalization of the filler particles in enhancing the latent heat storage and thermal and mechanical properties of the polymer composites, suggesting their potential application across diverse fields.

Exploring contaminants and analyte adsorption on functionalized porous silicon: Insights from a combined theoretical and experimental approach

Porous Silicon (PSi) holds significant promise in the realm of biosensor fabrication, due to its biocompatibility, large surface area, ease of fabrication and surface modification. The majority of the studies in the literature are experimental, primarily emphasizing phenomenological aspect and lack a theoretical understanding of the processes involved. This study adopts a systematic theoretical approach that employs density functional theory (DFT) to examine PSi models functionalized with –O and –OH groups. Using 3-aminopropyltrimethoxysilane (APTMS) and (3-aminopropyl)triethoxysilane (APTES) as probes for interaction with PSi, the interplay between this system and analytes is explored considering some typical organic molecules such as caffeine (CF), paracetamol (PC), methylene blue (MB), and astaxanthin (ASX). The interactions between PSi and the silanes are of a covalent nature, whereas the attraction among the silanes and contaminants leans towards electrostatic forces, aided by van der Waals interactions. Theoretical absorption spectra indicated that the shifts in intensity help to identify analytes/contaminants, as they are related to the degree of pore functionalization. This modeling gained further clarity through experimental monitoring performed through reflective interference fast Fourier transform spectroscopy and validation using X-ray photoelectron spectroscopy measurements on porous silicon films. In addition to the fundamental understanding of the functionalization processes, this combined theoretical-experimental approach establishes groundwork for futuristic studies in the field of porous silicon based chemical/bio-sensors and tailoring/designing novel materials for enhanced selectivity towards the desired analytes.

Long-Lived Room-Temperature Phosphorescence from Silica Nanoparticles with In Situ Generated Carbonaceous Defects for Blue Organic Light-Emitting Diodes.

In this study, in situ formed silica nanoparticles (SNPs) emitting second-level phosphorescence at room temperature without a phosphorescent dopant have been achieved for the first time. This phosphorescence is achieved through the simple in situ formation of carbonaceous defects (CDs) within the SNPs, followed by passivation of the CDs by a robust silica matrix. The CD in the SNPs, termed CD@SNPs, are synthesized by cross-linking tetraethyl orthosilicate (TEOS) and (3-aminopropyl)triethoxysilane (APTES), and these cross-linked components create a porous structure within the silica matrix. Upon calcination, the carbon-related structures within the pores deform, leading to the formation of CDs. Confined within a robust silica matrix, the molecular motion of the CD is restricted, facilitating the generation of a stable triplet state and suppressing nonradiative decay. Moreover, the robust silica matrix passivates the CD confined in the SNPs at a nanoscale. These comprehensive effects enable prolonged phosphorescence emission from the SNPs. In addition, these phosphorescence-emitting SNPs have been applied as dopants in the emissive layer of organic light-emitting diodes to realize blue light emission. This feature suggests the possibility of utilizing luminescent SNPs as light emitters in display technologies.

Preparation and characterization of HNTs@ZIF enhanced intrinsic flame retardant RTV silicone rubber

Phenylphosphonyl dichloride (BPOD) and 3-aminopropyltriethoxysilane (APTES) were used to prepare phosphorus-nitrogen hexaethoxysilane (BPTES). BPTES was then used for cross-linking and curing hydroxyl‑terminated room-temperature vulcanized (RTV) silicone rubber, providing intrinsic flame retardancy. In addition, halloysite (HNTs) is a kind of tubular silicate, taking advantage of its large aspect ratio, HNTs were used as a template to load ZIF67 on the surface of halloysite to obtain HNTs@ZIF tubular filler. It was added to the above system as a reinforcing and flame-retardant filler by physical blending, and the RTV elastomer with excellent performance was prepared. The successful preparation of phosphorus-containing crosslinkers (BPTES) was demonstrated by FT-IR. After the introduction of the new crosslinker, RTV not only has improved flame retardant performance, but also improved mechanical properties. The tensile strength and elongation at break of RTV with 20 wt.% BPTES are increased by 151 % and 211 %, respectively. The peak heat release rate (pHRR) and the peak of smoke production rate (pSPR) are reduced by 55.9 % and 48.6 %, respectively, and the thermal stability is also improved. In addition, the successful preparation of HNTs@ZIF was confirmed by FT-IR, XRD, XPS, and TEM. By introducing 2 wt.% HNTs@ZIF into 20 wt.% BPTES cured RTV, the intrinsically flame-retardant RTVs with enhanced performance were prepared. It is worth noting that when 2 wt.% HNTs@ZIF is added, the flame retardant and smoke suppression properties of phosphorus-containing silicone rubber are further improved. Because the ZIF contains cobalt metal ions that can be catalyzed into carbon. The pHRR and pSPR decrease by 18.3 % and 16.3 %, respectively, and the total heat release (THR) and total smoke production (TSP) decrease by 23.6 % and 24.4 %, respectively. This work will provide enlightenment for the study of intrinsic flame-retardant RTVs enhanced by modified halloysite.

Comparison of protein immobilization methods with covalent bonding on paper for paper-based enzyme-linked immunosorbent assay

In this study, two methods were examined to optimize the immobilization of antibodies on paper when conducting a paper-based enzyme-linked immunosorbent assay (P-ELISA). Human IgG, as a test-capture protein, was immobilized on paper via the formation of Schiff bases. Aldehyde groups were introduced onto the surface of the paper via two methods: NaIO4 and 3-aminopropyltriethoxysilane (APTS) with glutaraldehyde (APTS-glutaraldehyde). In the assay, horseradish peroxidase-conjugated anti-human IgG (HRP-anti-IgG) binds to the immobilized human IgG, and the colorimetric reaction of 3,3′,5,5′-tetramethylbenzyzine (TMB) produces a blue color in the presence of H2O2 and HRP-anti-IgG as a model analyte. The immobilization of human IgG, the enzymatic reaction conditions, and the reduction of the chemical bond between the paper surface and immobilized human IgG all were optimized in order to improve both the analytical performance and the stability. In addition, the thickness of the paper was examined to stabilize the analytical signal. Consequently, the APTS-glutaraldehyde method was superior to the NaIO4 method in terms of sensitivity and reproducibility. Conversely, the reduction of imine to amine with NaBH4 proved to exert only minimal influence on sensitivity and stability, although it tended to degrade reproducibility. We also found that thick paper was preferential when using P-ELISA because a rigid paper substrate prevents distortion of the paper surface that is often caused by repeated washing processes.

Sustainable hydrophobic coating of paper utilizing silica nanoparticles

The preparation of hydrophobic paper involved applying thin layers of non-biodegradable plastics to the paper, which made recycling difficult and contributed to microplastic pollution. In this study, we present a new method for coating paper to enhance its hydrophobic properties and long-term effectiveness of the hydrophobic surface. We use sustainable materials such as polyvinyl alcohol (PVOH), chitosan, monoaminopropyl terminated polydimethylsiloxane (PDMS), and silica nanoparticles (SiNPs). We use hexamethylene diisocyanate isocyanurate trimer (HDIT) and (3-aminopropyl)triethoxysilane (APTES) to link the chemicals covalently and to modify surface of SiNPs with amino groups, respectively. We also integrate PVOH to reduce the cost of the coating solution without compromising its hydrophobicity. We confirmed the long-lasting hydrophobicity of the coated paper by measuring the water contact angle for 60 min. When the paper coated with a solution containing amino SiNPs dispersed in ethanol, the maximum contact angle at 10 s and at 1 h were 132.3° and 95.7°, respectively. Additionally, the hydrophobic coating solution can be removed for potential recycling by treating it with hydrochloric acid or acetic acid. Our developed coating solution provides an environmentally friendly option for various paper-based applications, promoting paper recycling and contributing to sustainable development and environmental protection efforts.

A novel molecularly imprinted nanobifunctional silica probe on the surface of black phosphorus nanosheets for the determination of trace norfloxacin by its catalytic amplification in RRS

A new black phosphorus nanosheets loaded with gold nanoparticles (BPNs-Au) by in-situ reduction procedure were prepared. Using BPNs-Au as the substrate, norfloxacin (NOR) as the template molecule, and 3-aminopropyltriethoxysilane (APTES) as the functional monomer, a surface molecularly imprinted nanosilica probes (BPNs-Au@MIP) with high catalytic properties were rapidly synthesized by the reversed-phase emulsion procedure, and the probes were also characterized in details. It was found that the BPNs-Au@MIP nanoprobe could specifically recognize NOR and had a strong catalytic effect on the nanogold indication reaction of ethanedioic acid-chloroauric acid. The generated AuNPs exhibit strong resonance Rayleigh scattering (RRS) effect and RRS was used as monitoring technique for the nano indicator reaction. After the addition of NOR, the catalytic sites of the nanoprobe were blocked by it, the catalytic activity was reduced, and the RRS signal was linearly weakened. As a result, we constructed a new RRS analysis platform for highly sensitive and selective determination of 0.0625–0.5 nmol/L NOR, with a detection limit of 0.035 nmol/L NOR. The method has been used for the determination of NOR in real samples, and the relative standard deviations (RSDs) were in the range of 3.54–7.43 %, with the recovery of 89.8–109.7 %.

Improving adhesion strength between steel and 2K polyurethane containing organic–inorganic hybrid nanoparticles and its performance optimization

This research has developed a novel adhesion promoter using organic-inorganic hybrid nanoparticles (ATS) to address existing limitations, such as the cumbersome separate coating and drying stages and insufficient adhesion. ATS was synthesized through hydrolysis-condensation reactions of an alkoxysilane-functionalized amphiphilic polymer (AFAP) precursor and 3-aminopropyltriethoxysilane (APTES). When directly mixed with resin part of polyurethane, ATS significantly enhanced the adhesion strength of 2 K PU to steel substrates without altering the mechanical properties or chemical structure of the polyurethane. An optimization process was conducted to determine the ideal mixing ratio of ATS with other components of 2 K PU, including different types of glycols (butylene glycol, propylene glycol, and ethylene glycol) and polyols to achieve the highest adhesive performance. The results showed that 2 K PU resin formed by using a mixture of polycaprolactone diol (PCD) and butylene glycol (BG) containing ATS (1−2) with nanoscale size (30.86 nm) exhibited superior adhesion performance over the other modified 2 K PUs and was 2.16 times higher than the common 2 K PU. These results were further validated via predictive model following response surface methodology to assess the precise impact of three parameters: the amount of AFAP (X1), amount of APTES (X2), and amount of BG (X3) on the adhesion strength of 2 K PU. The properties of different types of ATS and modified 2 K PU including particle size, degree of condensation, moisture content, molecular structure, molecular weight, hydrogen bonding intensity, microstructure morphology, and adhesion strength, were characterized.

Achieving the hydrophobic alteration by functionalized nano-silica for improving shale hydration inhibition

Shale hydration is the primary cause of wellbore instability during drilling processes. In this study, two non-fluorinated silane-coupling agents, octyltriethoxysilane (OTES) and (3-Aminopropyl) triethoxysilane (APTES), were grafted onto the nano-silica surface to develop a hydrophobic material (SHM). Various performance characterizations, including infrared spectroscopy, thermogravimetric analysis, surface tension, wetting alteration, capillary self-suction height, bentonite expansion, and shale dispersion, were employed to investigate the shale inhibition properties of SHM comprehensively. Experimental results revealed that SHM could significantly improve shale hydration inhibition. For instance, in a 2 % SHM liquids, the shale hot rolling recovery rate increased from 25.39 % to 83.78 %, and the bentonite expansion height decreased from 7.65 mm to 2.80 mm. The inhibition performance was notably superior to potassium chloride (KCl) and polyether amine (PEA). Inhibition mechanisms analysis unveiled that the outstanding inhibitory effect of SHM was achieved through electrostatic adsorption, wettability alteration, and surface tension reduction. Firstly, SHM contained numerous amine groups that could demonstrate strong adsorption on the clay surface through electrostatic and hydrogen bonding interactions. Secondly, with long hydrophobic alkyl chains, it formed a highly hydrophobic film enveloping the shale surface, effectively preventing water from invading. Thirdly, it reduced liquid surface tension, further minimizing the water infiltration. As a result, the use of SHM significantly enhanced shale hydration inhibition during the shale drilling process.

Modeling and Sensitivity Estimation of a Dual Cavity Source Pocket-Based Charge Plasma Tunneling FET for Label-Free Biological Molecule Detection

A dual-source cavity charge plasma tunneling FET (DSC-SP-CPTFET) with SiGe Pocket is proposed, and its effectiveness as a biological sensor for label-free detection is explored. The fabrication complexity and cost have been reduced by using the charge-plasma concept. For improved sensing, an etched nanocavity is added to the upper and lower of the source metal section. The high-k (HfO2) gate oxide and minimal energy gap (Si0.6Ge0.4) alloy with a 40% mole fraction improve the current sensitivity by enhancing the drain current gradient. The sensitivity of the suggested biological sensor is assessed here for several neutral biological molecules, such as Gelatin, Keratin, Biotin, and 3-Aminopropyl-Triethoxysilane (APTES). Deoxyribonucleic acid (DNA), a charged biological molecule, is also considered with varying positive and negative charge densities. The suggested biological sensor shows a (SIDS)max of 2.21 × 1010 and a Sratio of 3.11 × 109 for biological molecules with higher dielectric constant at room temperature. Different electrostatic performances are estimated in the ON state, including energy band, electron (e-) BTBT rate, electrical field, and IDS-VGS characteristics. In addition, the proposed biological sensor provides a much superior drain current sensitivity (SIDS), current ratio sensitivity (Sratio), and average SS sensitivity (SSS) performance in the presence of both charged and neutral biological molecules.

Nitrogen–silicon Co-doped carbon dots synthesized based on lemon peel for copper (II) detection via a dynamic quenching mechanism

As a metal, copper plays an important role in biological systems. However, excessive intake can lead to toxicity and disease. Therefore, there is a need to establish accurate and sensitive methods to detect and monitor copper levels in food and the environment. Herein, nitrogen-silicon co-doped carbon dots (N,Si-CDs) were synthesized using lemon peel as the biomass precursor by one-step hydrothermal synthesis with the addition of citric acid solution and 3-aminopropyl triethoxysilane (APTES). The prepared N,Si-CDs showed excellent photobleaching resistance, brilliant fluorescence performance and good selectivity. The experiments showed that the fluorescence of N,Si-CDs decreased after the interaction of N,Si-CDs with copper ions. Further studies showed that the decrease in fluorescence intensity of the fluorescent probe due to Cu2+ was dynamic quenching. In addition, the fluorescence intensity of N,Si-CDs showed a good linear relationship with the concentration of copper ions. The linear range was 0.5 μM–250 μM, the R2 was 0.995, and the limit of detection was 0.43 μM. Finally, the method has been successfully applied to the detection of copper ions in the water environment and food, and the recoveries of 99.4%–102.1 % were obtained, which indicated that the method had a promising future.

Low temperature carbonization, smoke suppression and durable flame retardancy of cotton fabric spray-assisted coated by phosphorus nitrogen silicon composite system

To solve the problems of flammability, smoldering, smoking and flame retardant durability of cotton fabric, flame retardant fininshing was executed using spray assisted self-assembly method, and P/N/Si synergistic flame retardant system was constructed by polyethylene imine (PEI), phytic acid (PA) and 3-aminopropyltriethoxysilane (APTES). Cotton cellulose carbonized at low temperature prompting by PA catalytic effect, and this cooperated with PEI thermal decomposition to endow cotton fabric with flame retardancy and smoking suppression by reducing its pyrolysis rate at high temperature and lessening combustible products. Meanwhile APTES as silane coupling agent further improved its flame retardant durability and smoke suppression effect. The synchronous thermal analysis results indicate that cotton fabrics treated by PA/PEI/APTES composite system present significant low-temperature carbonization trend, and their initial decomposition temperatures advance by 46.5℃-75.9℃. Moreover, they form 4.6 %-44.9 % aromatic structure char through dehydration and carbonization reactions during the low-temperature carbonization process, improving their thermal stability at high temperature, and their after-flame and smoldering phenomena disappear. The damaged length of treated fabric with five layers reduces to 5.0 cm, its limiting oxygen index reaches 33.7 %, and it presents excellent flame retardant durability and smoke suppression effect. This low-temperature carbonization mechanism possesses importantly innovative significance for the flame retardant finishing of cotton fabric, and it not only more actively guides the selection of flame retardants to make them match with the material required, but provides a new thinking method for flame retardant material research in the future.

Development of Halloysite Nanotube-Infused Thermoset Soybean Bio-Resin for Advanced Medical Packaging.

The development of eco-friendly, mechanically stable, and biocompatible materials for medical packaging has gained significant attention in recent years. Halloysite nanotubes (HNTs) have emerged as a promising nanomaterial due to their unique tubular structure, high aspect ratio, and biocompatibility. We aim to develop a novel soybean oil-based thermoset bio-resin incorporating HNTs and to characterize its physical and functional properties for medical packaging. Soybean oil was epoxidized using an eco-friendly method and used as a precursor for preparing the thermoset resin (ESOR). Different amounts of HNTs (0.25, 0.50, and 1.0 wt.%) were used to prepare the ESOR/HNTs blends. Various characteristics such as transparency, tensile strength, thermal resistance, and water absorption were investigated. While incorporating HNTs improved the tensile strength and thermal properties of the ESOR, it noticeably reduced its transparency at the 1.0 wt.% level. Therefore, HNTs were modified using sodium hydroxide and (3-Aminopropyl) triethoxysilane (APTES) and ESOR/HNTs blends were made using 1.0 wt.% of modified HNTs. It was shown that modifying HNTs using NaOH improved the transparency and mechanical properties of prepared blends compared to those with the same amount of unmodified HNTs. However, modifying using (3-Aminopropyl) triethoxysilane (APTES) decreased the transparency but improved the water absorption of prepared resins. This study provides valuable insights into the design of HNT-based ESOR blends as a sustainable material for medical packaging, contributing to the advancement of eco-friendly packaging solutions in the healthcare industry.

Ti3C2Tx MXene-assisted solar-driven CO2 adsorption and photothermal regeneration over mesoporous SiO2

Due to the high energy consumption associated with regenerating adsorbents with high carbon dioxide adsorption capacity, utilizing renewable solar energy as an alternative to traditional thermal energy for photothermally regenerating adsorbents is a feasible approach. In this research, a solar-induced regeneration technique has been formulated, employing fumed silica as the framework, MXene as the photothermal conversion component, and (3-aminopropyl)triethoxysilane (APTES) as the site for carbon dioxide adsorption. The findings suggest that incorporating MXene can substantially enhance the photoresponsive and photothermal conversion properties of aminosilica. Beneath an brightening concentrated of 1 kW·m−2, aminosilica@MXene(7 wt%) reaches a maximum temperature of 76.8 °C, compared to only 53.4 °C when using aminosilica alone. Notably, aminosilica@MXene (7 wt%) achieves complete desorption at an illumination intensity of 2 kW·m−2. Through multiple cycling tests, aminosilica@MXene (7 wt%) demonstrates outstanding recyclability. As a result, using solar energy to power the adsorbent photothermal regeneration turns into a useful strategy for lowering the energy required for regeneration.

Generalized Multifunctional Coating Strategies Based on Polyphenol-Amine-Inspired Chemistry and Layer-by-Layer Deposition for Blood Contact Catheters.

Blood-contacting catheters play a pivotal role in contemporary medical treatments, particularly in the management of cardiovascular diseases. However, these catheters exhibit inappropriate wettability and lack antimicrobial characteristics, which often lead to catheter-related infections and thrombosis. Therefore, there is an urgent need for blood contact catheters with antimicrobial and anticoagulant properties. In this study, we employed tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) to create a stable hydrophilic coating under mild conditions. Heparin (Hep) and poly(lysine) (PL) were then modified on the TA-APTES coating surface using the layer-by-layer (LBL) technique to create a superhydrophilic TA/APTES/(LBL)4 coating on silicone rubber (SR) catheters. Leveraging the superhydrophilic nature of this coating, it can be effectively applied to blood-contacting catheters to impart antibacterial, antiprotein adsorption, and anticoagulant properties. Due to Hep's anticoagulant attributes, the activated partial thromboplastin time and thrombin time tests conducted on SR/TA-APTES/(LBL)4 catheters revealed remarkable extensions of 276 and 103%, respectively, when compared to uncoated commercial SR catheters. Furthermore, the synergistic interaction between PL and TA serves to enhance the resistance of SR/TA-APTES/(LBL)4 catheters against bacterial adherence, reducing it by up to 99.9% compared to uncoated commercial SR catheters. Remarkably, the SR/TA-APTES/(LBL)4 catheter exhibits good biocompatibility with human umbilical vein endothelial cells in culture, positioning it as a promising solution to address the current challenges associated with blood-contact catheters.

Ag Doping and rGO Coupling of TiO<sub>2</sub> within Polysiloxane Matrix for the Ecofriendly Development of High-Performance Cotton Fabric

In this work, TiO2 was applied to cotton fabric by a sol–gel-hydrothermal process. A combination of 3-(trihydroxysilyl) propyl methylphosphonate monosodium salt solution (TPMP) and (3-aminopropyl)triethoxysilane (APTES) was used as a matrix to enhance the interfacial interaction between TiO2 and surface of the cotton fibres. During the hydrothermal treatment, silver nitrate (AgNO3) or reduced graphene oxide (rGO) were added to produce Ag-doped TiO2- or rGO-coupled TiO2-coated textiles. The successful application of all investigated components on cotton fabric was confirmed by the analysis of SEM and EDS. The results of UPF determination and self-cleaning activity showed excellent performance of both studied nanocomposite coatings, whereas the use of rGO proved to be better than Ag.

XPS and ARXPS for Characterizing Multilayers of Silanes on Gold Surfaces

X-ray photoelectron spectroscopy (XPS) and angle-resolved XPS (ARXPS) characterization of surface layers resulting from the functionalization of polymers such as polyvinylchloride (PVC) modified with 3(mercaptopropyl)-trimethoxysilane (MPTMS) and (3-aminopropyl) triethoxysilane (APTES) is challenging due to the overlap in signals, deriving both from the substrate and the functionalized layers. In this work, a freshly cleaved, ideally flat gold surface was used as carbon-free model substrate functionalized with MPTMS and subsequently grafted with APTES. Avoiding the overlap of signals from carbon atoms present in the substrate, the signals in the C1s, O1s, Si2p, S2p and N1s high-resolution spectra could be assigned to the MPTMS/APTES functionalized layer only and the curve-fitting parameters could be determined. Quantitative analysis was in very good agreement with the expected stoichiometry of the functionalized layer, confirming the adopted curve-fitting procedure. In addition, it was found that one molecule of APTES grafted two MPTMS via silane groups. ARXPS allowed for determining the thickness of the functionalized layers: MPTMS thickness was found to be 0.5 (0.2) nm, whereas MPTMS + APTES thickness 1.0 (0.2) nm was in good agreement with Avogadro model calculations. This approach can be considered a powerful tool for characterizing functionalized surfaces of more complex systems by XPS.

Mussel-inspired superhydrophilic and antibacterial membranes for effective gravity-driven separation of oil-in-water emulsions

Substantial discharge of industrial oily wastewater calls for an efficient and sustainable treatment for resource recovery. Superwetting membranes offer a feasible approach to fractionate oil species and water from oily wastewater for addressing this technical challenge. In this study, we proposed a useful strategy for constructing a superhydrophilic membrane with superior antibacterial properties through rapid co-deposition of dopamine and 3-aminopropyltriethoxysilane (APTS) initiated by ammonium persulfate on the Cu nanoparticles-loaded porous PVDF substrate. The resultant superhydrophilic membrane yielded an underwater oil contact angle of 163.5°, enabling a fast and robust gravity-driven filtration for various oil-in-water emulsions with a separation efficiency of >99.9 %. Additionally, incorporating of Cu nanoparticles and polydopamine endowed the superhydrophilic membrane with superior antibacterial activity (100 % inhibition efficiency against Escherichia coli), and thereby remarkably enhancing the anti-biofouling performance. This study provides a viable approach to design high-performance membranes for separation of oil-in-water emulsions, with promising applications in the industrial and environmental sectors.

Enhanced mechanical properties and environmental stability of polymer-bonded magnets using three-step surface wet chemical modifications of Nd–Fe–B magnetic powder

This research focuses on the surface modification of Nd–Fe–B magnetic powder to enhance its thermal and oxidation resistance without compromising magnetic properties and to improve adhesion to the polymer binder for enhanced mechanical properties. A three-step surface modification process involving phosphatization treatment, tetraethyl orthosilicate (TEOS) application, and 3-aminopropyltriethoxysilane (APTES) grafting, was applied to the powder, which was then compounded with polyamide 12 and injection-moulded into cylinders and dog-bone-shaped tubes. The resulting magnets exhibited remanence (Br) of 487.6 mT, coercivity (Hci) of 727.7 kA/m, and energy product (BHmax) of 39.3 kJ/m3. The modified magnets demonstrated exceptional corrosion resistance and thermal stability, with less than 5% irreversible flux loss after exposure to hot water, temperature shock, and pressurised steam. Furthermore, the modified magnets displayed significantly higher tensile strength, elongation at break, and elastic modulus with improvements of 62%, 16.7%, and 19.9%, respectively, compared to the non-modified batch. Additionally, the modified batch showed a notable 52% increase in flexural stress during flexural testing. These findings underscore the potential of silane surface modifications in producing injection-moulded permanent magnets based on Nd–Fe–B alloy, extending their shelf life and enhancing their overall performance.