Grafting Hyperbranched Polymers onto TiO2 Nanoparticles via Thiol-yne Click Chemistry and Its Effect on the Mechanical, Thermal and Surface Properties of Polyurethane Coating

In this study, we proposed a novel and facile method to modify the surface of TiO2 nanoparticles and investigated the influence of the surface-modified TiO2 nanoparticles as an additive in a polyurethane (PU) coating. The hyperbranched polymers (HBP) were grafted on the surface of TiO2 nanoparticles via the thiol-yne click chemistry to reduce the aggregation of nanoparticles and increase the interaction between TiO2 and polymer matrices. The grafting of HBP on the TiO2 nanoparticles surface was investigated by means of X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) and thermogravimetry analysis (TGA). The thermal and mechanical properties of nanocomposite coatings containing various amounts of TiO2 nanoparticles were measured by dynamic mechanical thermal (DMTA) and tensile strength measurement. Moreover, the surface structure and properties of the newly prepared nanocomposite coatings were examined. The experimental results demonstrate that the incorporation of the surface-modified TiO2 nanoparticles can improve the mechanical and thermal properties of nanocomposite coatings. The results also reveal that the surface modification of TiO2 with the HBP chains improves the nanoparticle dispersion, and the coating surface shows a lotus leaf-like microstructure. Thus, the functional nanocomposite coatings exhibit superhydrophobic properties, good photocatalytic depollution performance, and high stripping resistance.

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α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽

10.3390/polym13040581 ◽

2021 ◽

Vol 13 (4) ◽

pp. 581

Author(s):

Gajanan S. Ghodake ◽

Surendra K. Shinde ◽

Ganesh D. Saratale ◽

Rijuta G. Saratale ◽

Min Kim ◽

...

Keyword(s):

Enzyme Immobilization ◽

Photoelectron Spectroscopy ◽

Cellulose Fibers ◽

Relative Activity ◽

Significant Activity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Laccase Immobilization ◽

Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

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Anodic ZnO Microsheet Coating on Zn with Sub-Surface Microtrenched Zn Layer Reduces Risk of Localized Corrosion and Improves Bioactivity of Pure Zn

Coatings ◽

10.3390/coatings11050486 ◽

2021 ◽

Vol 11 (5) ◽

pp. 486

Author(s):

Hongzhou Dong ◽

Sannakaisa Virtanen

Keyword(s):

Photoelectron Spectroscopy ◽

Localized Corrosion ◽

Corrosion Performance ◽

X Ray Diffraction ◽

Biodegradable Implant ◽

X Ray ◽

Zinc Surface ◽

Microstructured Surface ◽

Coated Surface ◽

Surface Modified

Zinc-based alloys are emerging as an alternative to magnesium- and iron-based alloys for biodegradable implant applications, due to their appropriate corrosion performance and biocompatibility. However, localized corrosion occurring on the zinc surface, which is generally associated with restricted mass transport at specific surface sites, such as in confined crevices, declines mechanical strength and can lead to the failure of implant materials. In order to improve corrosion behavior and bioactivity, we explore the effect of a ZnO microsheet coating fabricated on pure Zn via anodic oxidization. Samples were characterized with Scanning Electron Microscope (SEM) (including Energy Dispersive Spectroscopy (EDS), X-ray Photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD)). The microstructured surface consists of parallel Zn trenches on the bottom and ZnO/Zn3O(SO4)2 sheets on the top. This layer shows favorable Ca-phosphate precipitation as well as bovine serum albumin (BSA) adsorption properties. Electrochemical experiments indicate an increased corrosion resistance of surface-modified Zn by the presence of BSA in simulated body fluid. Most noteworthily, localized corrosion that has been previously observed for pure Zn in BSA-containing electrolytes does not occur on the Zn/ZnO-coated surface.

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Synthesis of High Crystalline TiO2 Nanoparticles on a Polymer Membrane to Degrade Pollutants from Water

Catalysts ◽

10.3390/catal8090376 ◽

2018 ◽

Vol 8 (9) ◽

pp. 376 ◽

Cited By ~ 19

Author(s):

Kristina Fischer ◽

Paulina Schulz ◽

Igor Atanasov ◽

Amira Abdul Latif ◽

Isabell Thomas ◽

...

Keyword(s):

Photocatalytic Activity ◽

Tio2 Nanoparticles ◽

Photoelectron Spectroscopy ◽

Large Scale ◽

Synthesis Temperature ◽

Nanoparticle Dispersion ◽

X Ray ◽

Innovative Method ◽

Water Cleaning ◽

Photocatalytic Tio2

Titanium dioxide (TiO2) is described as an established material to remove pollutants from water. However, TiO2 is still not applied on a large scale due to issues concerning, for example, the form of use or low photocatalytic activity. We present an easily upscalable method to synthesize high active TiO2 nanoparticles on a polyethersulfone microfiltration membrane to remove pollutants in a continuous way. For this purpose, titanium(IV) isopropoxide was mixed with water and hydrochloric acid and treated up to 210 °C. After cooling, the membrane was simply dip-coated into the TiO2 nanoparticle dispersion. Standard characterization was undertaken (i.e., X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, water permeance, contact angle). Degradation of carbamazepine and methylene blue was executed. By increasing synthesis temperature crystallinity and photocatalytic activity elevates. Both ultrasound modification of nanoparticles and membrane pre-modification with carboxyl groups led to fine distribution of nanoparticles. The ultrasound-treated nanoparticles gave the highest photocatalytic activity in degrading carbamazepine and showed no decrease in degradation after nine times of repetition. The TiO2 nanoparticles were strongly bound to the membrane. Photocatalytic TiO2 nanoparticles with high activity were synthesized. The innovative method enables a fast and easy nanoparticle production, which could enable the use in large-scale water cleaning.

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Enhanced Mechanical and Thermal Properties of Stereolithography 3D Printed Structures by the Effects of Incorporated Controllably Annealed Anatase TiO2 Nanoparticles

Nanomaterials ◽

10.3390/nano10010079 ◽

2020 ◽

Vol 10 (1) ◽

pp. 79 ◽

Cited By ~ 2

Author(s):

Suhail Mubarak ◽

Duraisami Dhamodharan ◽

Nidhin Divakaran ◽

Manoj B. Kale ◽

T. Senthil ◽

...

Keyword(s):

Tio2 Nanoparticles ◽

Photoelectron Spectroscopy ◽

Uv Light ◽

Anatase Phase ◽

Low Energy ◽

Mechanical And Thermal Properties ◽

Tem Analysis ◽

X Ray ◽

Energy Bandgap ◽

3D Printed

Fabrication of low-cost, durable and efficient metal oxide nanocomposites were successfully synthesized and reinforced with photo-resin via 3-dimensional printing. Here, we put forward a novel approach to enhance the mechanical and thermal behaviors of stereolithography (SLA) 3D printed architecture by adding TiO2 nanoparticles (TNPs) in different crystalline phases (anatase and rutile), which were obtained at different annealing temperatures from 400 °C to 1000°C. The heat-treated anatase TNPs were scrutinized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, diffusive reflectance spectroscopy (DRS), and transmission electron microscopy (TEM) analysis. Among all the samples, at 800 °C, annealed anatase TNPs exposed a highly crystalline anatase phase, having a low energy bandgap and a comparably high tensile strength (47.43 MPa) and high elastic modulus (2.261 GPa) for the 3D printed samples, showing improvement by 103% and 32%, respectively, compared with the printed pristine stereolithography resin (SLR) sample. Moreover, enhanced storage modulus and tan δ values were achieved via the better interfacial interactions between the incorporated nanofillers and the SLR matrix. In addition to this, enhanced thermal conductivity and thermal stability of the SLR matrix were also noted. The low energy bandgap and nanoscale size of the fillers helped to achieve good dispersion and allowed the UV light to penetrate at a maximum depth through the photo resin.

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Production of nearly monodisperse Fe3O4 and Fe@Fe3O4 nanoparticles in aqueous medium and their surface modification for biomedical applications

International Journal of Modern Physics B ◽

10.1142/s021797921750014x ◽

2017 ◽

Vol 31 (04) ◽

pp. 1750014 ◽

Cited By ~ 1

Author(s):

Tirusew Tegafaw ◽

Wenlong Xu ◽

Sang Hyup Lee ◽

Kwon Seok Chae ◽

Yongmin Chang ◽

...

Keyword(s):

Aqueous Medium ◽

Photoelectron Spectroscopy ◽

Quantum Interference ◽

Biomedical Applications ◽

Ir Absorption ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Surface Modified ◽

Surface Modified Nanoparticles

Iron (Fe)-based nanoparticles are extremely valuable in biomedical applications owing to their low toxicity and high magnetization values at room temperature. In this study, we synthesized nearly monodisperse iron oxide (Fe3O4) and Fe@Fe3O4 (core: Fe, shell: Fe3O[Formula: see text] nanoparticles in aqueous medium under argon flow and then, coated them with various biocompatible ligands and silica. In this study, eight types of surface-modified nanoparticles were investigated, namely, Fe3O4@PAA (PAA = polyacrylic acid; [Formula: see text] of PAA = 5100 amu and 15,000 amu), Fe3O4@PAA–FA (FA = folic acid; [Formula: see text] of PAA = 5100 amu and 15,000 amu), Fe3O4@PEI–fluorescein (PEI = polyethylenimine; [Formula: see text] of PEI = 1300 amu), Fe@Fe3O4@PEI ([Formula: see text] of PEI = 10,000 amu), Fe3O4@SiO2 and Fe@Fe3O4@SiO2 nanoparticles. We characterized the prepared surface-modified nanoparticles using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) absorption spectroscopy, a superconducting quantum interference device (SQUID), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and confocal microscopy. Finally, we measured the cytotoxicity of the samples. The results indicate that the surface-modified nanoparticles are biocompatible and are potential candidates for various biomedical applications.

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Synthesis of surface-metallized polymeric films by in situ reduction of (4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionato) silver(I) in a polyimide matrix

Journal of Materials Research ◽

10.1557/jmr.1999.0387 ◽

1999 ◽

Vol 14 (7) ◽

pp. 2897-2904 ◽

Cited By ~ 5

Author(s):

Robin E. Southward ◽

Carey K. Bagdassarian ◽

Christopher J. Sudol ◽

Jennifer L. Wasyk ◽

Susanna H. Sproul ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Composite Films ◽

Mechanical And Thermal Properties ◽

Gravimetric Analysis ◽

Face Centered Cubic ◽

Thermal Curing ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray

Thermal curing of the (4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionato)silver(I)-containing poly(amic acid) formed from 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride (BTDA) and 4,4′-oxydianiline (4,4′-ODA) in dimethylacetamide gives both polyimide films via cyclodehydration and reduction of silver(I) to the native metal. Silver(0) migrates to the surface resulting in surface metallized composite films, which can have excellent reflectivity, but do not exhibit surface electrical conductivity. The films retain mechanical and thermal properties similar to those of the parent polyimide. X-ray diffraction shows crystalline face-centered-cubic silver in the films after thermal curing. Microscopy data show that the surface particle sizes are in the range of approximately 50–100 nm. Significant silver remains in the bulk of the polyimide film with varying particles sizes generally less than approximately 15 nm. The interior of the metallized films is not electrically conducting. Films were characterized by x-ray diffraction, differential scanning calorimetry, thermal gravimetric analysis, x-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, and mechanical measurements.

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Comprehensive Evaluation of the Biological Properties of Surface-Modified Titanium Alloy Implants

Journal of Clinical Medicine ◽

10.3390/jcm9020342 ◽

2020 ◽

Vol 9 (2) ◽

pp. 342 ◽

Cited By ~ 5

Author(s):

Piszczek ◽

Radtke ◽

Ehlert ◽

Jędrzejewski ◽

Sznarkowska ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Comprehensive Evaluation ◽

Chemical Vapor ◽

Orthopedic Implants ◽

Biological Properties ◽

X Ray Diffraction ◽

Implant Surface ◽

X Ray ◽

Incubation Experiments ◽

Surface Modified

An increasing interest in the fabrication of implants made of titanium and its alloys results from their capacity to be integrated into the bone system. This integration is facilitated by different modifications of the implant surface. Here, we assessed the bioactivity of amorphous titania nanoporous and nanotubular coatings (TNTs), produced by electrochemical oxidation of Ti6Al4V orthopedic implants’ surface. The chemical composition and microstructure of TNT layers was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). To increase their antimicrobial activity, TNT coatings were enriched with silver nanoparticles (AgNPs) with the chemical vapor deposition (CVD) method and tested against various bacterial and fungal strains for their ability to form a biofilm. The biointegrity and anti-inflammatory properties of these layers were assessed with the use of fibroblast, osteoblast, and macrophage cell lines. To assess and exclude potential genotoxicity issues of the fabricated systems, a mutation reversal test was performed (Ames Assay MPF, OECD TG 471), showing that none of the TNT coatings released mutagenic substances in long-term incubation experiments. The thorough analysis performed in this study indicates that the TNT5 and TNT5/AgNPs coatings (TNT5—the layer obtained upon applying a 5 V potential) present the most suitable physicochemical and biological properties for their potential use in the fabrication of implants for orthopedics. For this reason, their mechanical properties were measured to obtain full system characteristics.

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Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

MRS Proceedings ◽

10.1557/proc-780-y5.5 ◽

2003 ◽

Vol 780 ◽

Author(s):

C. Essary ◽

V. Craciun ◽

J. M. Howard ◽

R. K. Singh

Keyword(s):

Uv Radiation ◽

Photoelectron Spectroscopy ◽

Grazing Angle ◽

X Ray Diffraction ◽

Metal Thin Films ◽

X Ray ◽

Force Microscopy ◽

Si Substrates ◽

Atomic Force ◽

Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

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Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽

10.3390/catal11030346 ◽

2021 ◽

Vol 11 (3) ◽

pp. 346

Author(s):

Sonam Goyal ◽

Maizatul Shima Shaharun ◽

Ganaga Suriya Jayabal ◽

Chong Fai Kait ◽

Bawadi Abdullah ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalyst Support ◽

Oxidation Potential ◽

Molar Ratio ◽

X Ray Diffraction ◽

X Ray ◽

Molar Ratios ◽

Optimum Parameters ◽

Reduction Of Co2 ◽

Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

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Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

Coatings ◽

10.3390/coatings11080937 ◽

2021 ◽

Vol 11 (8) ◽

pp. 937

Author(s):

Yingying Hu ◽

Md Rasadujjaman ◽

Yanrong Wang ◽

Jing Zhang ◽

Jiang Yan ◽

...

Keyword(s):

Crystal Structure ◽

Optical Properties ◽

Photoelectron Spectroscopy ◽

Crystal Size ◽

Silicon Substrates ◽

X Ray Diffraction ◽

Dc Magnetron Sputtering ◽

Flow Rates ◽

X Ray ◽

N2 Flow Rate

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

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