High Level Of Crystallinity Research Articles

Influence of the toxic vapors on the gas sensitivity and structure of poly(o-toluidine)

In the present work, we investigated the influence of the toxic vapors (ammonia, chloroform, tetrahydrofuran, dimethylformamide, nitrobenzene, toluene) on the specific resistance, optical absorption, and structure of conducting polymer poly-o-toluidine (PoT) obtained by oxidative polymerization of o-toluidine in toluene sulfonic acid (TSA) solution. This polymer has a high level of crystallinity and is thermal stable to 473 K (200 0C). The action of organic solvent vapors causes an increase in PoT-TSA resistance by 1.3-1.4 times, while after the action of ammonia, the resistivity increases almost 500 times. The activation energy of charge transfer Ea also increases from 0.21 to 0.71 eV under the action of ammonia due to the deprotonation of the polymer and its transformation to the resistive base form. When the organic solvents are used, the observed phenomena have a different direction (resistance increase or decrease) due to the peculiarities of polymer-solvent molecular interaction. This phenomenon may be used for selective detection of solvents.

Potential nanomedicinal applications and physicochemical nature of Hyphaene thebaica-reduced nano-samaria.

Herein we described the biofabrication of samarium oxide nanoparticles (HT-Sm2O3 NPs) by applying the aqueous fruit extract of Hyphaene thebaica was utilized as an eco-friendly chelating agent. The prepared NPs were subjected to various physicochemical properties and potential in biomedical applications. X-ray Diffraction (XRD) pattern revealed sharp peaks that corroborated with the Joint Committee on Powder Diffraction Standards (JCPDS) card no. 00-042-1464. Crystallite size obtained from Debye-Scherrer approximation and Williamson-Hall (W-H) plot was 28.73 and 69.3 nm, respectively. Optical bandgap was calculated by employing Kubelka-Munk (K-M) function and was found to be ~4.58 eV. Raman shift was observed at 121, 351, 424-, and 561 cm-1. Photoluminescence (PL) spectra revealed two major peaks positioned at 360 and 540 nm. The high-resolution transmission electron microscopy (HR-TEM) analysis of HT-Sm2O3 nanoparticles (NPs) showed that they predominantly have spherical to cuboidal shapes. Additionally, the selected area electron diffraction (SAED) pattern presented spotty rings, indicating a high level of crystallinity in these NPs. The potential nanomedicine applications were studied using diverse bioassays using different treatments. The antioxidant activity demonstrated 45.71% ± 1.13% inhibition at 1000 μg/mL. Brine shrimp lethality assay revealed the highest cytotoxicity of 46.67% ± 3.33% at 1000 μg/mL and LC50 value of 1081 μg/mL. HT-Sm2O3 NPs exhibited inhibition of angiogenesis (20.41% ± 1.18%) at of 1000 μg/mL. MTT assay results indicated that HT-Sm2O3 NPs exhibit inhibitory effects on cell lines. Specifically, these NPs showed an IC50 value of 104.6 μg/mL against 3T3 cells. Against MCF-7 cells, the NPs demonstrated an IC50 value of 413.25 μg/mL. Additionally, in the inhibition of acetylcholinesterase (AChE), the newly synthesized NPs showed an IC50 value of 320 μg/mL. The antidiabetic assessment through α-glucosidase and α-amylase inhibition assays revealed, an IC50 value of 380 μg/mL for α-glucosidase and 952 μg/mL for α-amylase was calculated. Overall, our study suggested that the Sm2O3 NPs possess moderate anticancer, cholinesterase inhibition, and antidiabetic potential, however, needs further assessment. RESEARCH HIGHLIGHTS: In this work, nano-samaria is synthesized using an eco-friendly and green approach. The nanoparticles were characterized using techniques such as Raman, HR-TEM, FTIR, DRS, XRD, and so on, and the applications were studied using multiple in vitro bioassays for Diabetes, Alzheimer, and Cancer. The nano-samaria revealed good potential for potential biomedical applications.

Process parameters for enhanced microstructure and composition of as-sprayed Yb2Si2O7 environmental barrier coatings via atmospheric plasma spray

Achieving high crystallinity levels, dense, crack-free microstructures with near-stoichiometric phase composition and controlled secondary phase formation are crucial for enhancing the performance of environmental barrier coatings (EBCs). To investigate the impact of APS process parameters on the as-sprayed crystallinity, microstructure, and phase composition of Yb2Si2O7 EBCs, various spraying conditions were explored by adjusting torch power, nozzle size, powder feedrate, stand-off distance, and adding a shroud attachment to the torch. The velocity of particles controlled the density of the EBCs by an interplay between deposition efficiency and splat flattening ratios. Increasing nozzle size from 5/16″ to 1/2″ reduced particle velocity by up to 40 %, resulting in improved deposition efficiencies, porosity levels and coating thickness. However, larger nozzles led to higher silicon evaporation and up to 8 wt% more stable Yb2SiO5 (I2/a) secondary phase was formed. Increasing the stand-off distance from 50 mm had minimal effect on microstructure, but metastable Yb2SiO5 (P21/c) was detected (up to 9 wt%) at longer stand-off distances of 100 and 150 mm. Raising the powder feedrate from 15 gr/min to 60 gr/min improved deposition efficiency (up to 9 %) and density (up to 15 %) of EBCs, yet resulted in higher silicon-depleted phase formation (up to 12 wt%). Adding a shroud to the torch nozzle exit led to severe silicon evaporation and formation of up to 42 wt% and 6 wt% of Yb2SiO5 (I2/a) and Yb2O3, respectively. Moreover, due to the shroud's funnelling effect on smaller particles as well as particle overheating, porous microstructures with up to 28 % porosity levels were formed. High levels of crystallinity (∼75–91 %) were achieved in the as-sprayed condition for all the coatings, indicating real-time crystallization during spraying in all the spraying conditions.

Potential of Dimethyl Sulfoxide Modified Kaolin and Cetyl Trimethylammonium Bromide as Amoxycillin Adsorben

The large use of amoxicillin allows this antibiotic to enter the environment in large quantities and cause pollution. The adsorption technique can be used as a method to remove amoxicillin contaminants in wastewater by utilizing kaolin as an adsorbent. This study aims to determine the characteristics of kaolin as an adsorbent and determine the ability of kaolin to adsorb amoxicillin. Kaolin was activated with hydrochloric acid and modified using Dimethyl sulfoxide (DMSO) and cetyl trimethylammonium bromide (CTAB). The results showed that the characteristics of DMSO and CTAB-modified kaolin showed a new peak which was an O-H bending vibration in functional group analysis using FTIR. X-ray diffraction results show that the distance between planes in the kaolin structure is larger. Meanwhile, the results of the SEM analysis showed that the surface morphology of kaolin had a higher level of crystallinity than before which proved an increase in the adsorption capacity of kaolin. The adsorption kinetics follows the Santosa kinetic equation model with an adsorption rate of 0.004 min-1 and an equilibrium constant value of 0.007 L.mol-1 . The adsorption isotherm test follows the Freundlich isotherm equation model with an adsorption constant value of 561.694 L.mg-1 and an empirical constant value of 0.270.

Enhanced photocatalytic activity of magnetite/titanate (Fe3O4/TiO2) nanocomposite for methylene blue dye degradation under direct sunlight

In this study, we have presented findings on the structural, optical, morphological, magnetic and photocatalytic characteristics of magnetite/TiO2 nanocomposite (Fe3O4/TiO2 NCs) for the degradation of methylene blue (MB) dye under sunlight. The NCs were synthesized using a facile hydrothermal technique and subsequently subjected to analysis using several characterization methods, including XRD, Raman spectroscopy, SEM, UV–Vis and VSM. XRD analysis revealed that the as-prepared sample exhibited a high level of crystallinity, accompanied by a smaller crystallite size. The structural defects in the crystal system and the presence of impurities in the as-prepared sample can be analysed using Raman spectroscopy. Morphological studies represent the synthesized Fe3O4/TiO2 NCs are evenly arranged and are spherical in shape. The average particle size was determined through the utilization of image J software, yielding a measurement of 31 nm. UV–Vis spectrum shows the absorbance peak and the energy bandgap was calculated. The NCs, in their initial state, demonstrated a degradation efficiency exceeding 97% for MB dye under sunlight within duration of 40 min. The Fe3O4/TiO2 NCs possess the capability of effortless separation from the dye solution facilitated by an external magnet.

UV-Light-Driven Photocatalytic Dye Degradation and Antibacterial Potentials of Biosynthesized SiO2 Nanoparticles

The present work shows the obtainment of biosynthesized SiO2 with the aid of Jasminum grandiflorum plant extract and the study of its photocatalytic ability in dye degradation and antibacterial activity. The obtained biosynthesized SiO2 nanoparticles were characterized using X-ray diffractometer analysis, Fourier transform infrared spectroscopy analysis, ultraviolet–visible diffuse reflectance spectroscopy, field-emission scanning electron microscope with energy-dispersive X-ray analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. The UV-light irradiated photocatalytic activity of the biosynthesized SiO2 nanoparticles was examined using methylene blue dye solution. Its reusability efficiency was determined over 20 cycles and compared with the commercial P-25 titanium dioxide. The bacterial resistivity of the biosynthesized SiO2 nanoparticles was examined using S. aureus and E. coli. The biosynthesized SiO2 nanoparticles showed a high level of crystallinity with no impurities, and they had an optimum crystallite size of 23 nm, a bandgap of 4 eV, no Si-OH groups and quasi-spherical shapes with Si-2p at 104 eV and O-1s at 533 eV. Their photocatalytic activity on methylene blue dye solution could reach 90% degradation after 40 min of UV light exposure, and their reusability efficiency was only 4% less than that of commercial P-25 titanium dioxide. At the concentration of 100 μg/mL, the biosynthesized SiO2 nanoparticles could allow the resistivity of E. coli to become borderline to the resistant range of an antibiotic called Amikacin.

High surface quality heteroepitaxy α-Ga2O3 film on sapphire by mist-CVD technique

An ultra-flat heteroepitaxy α-Ga2O3 thin film, paved a glory future for device fabrication, was successfully obtained on a c-plane sapphire substrate through the employment of the mist chemical vapor deposition technique. Atomic force microscopy measurements revealed an root mean square (RMS) roughness value of 0.309 nm when the carrier gas flow rate was set at 1500 sccm. Furthermore, the full-width at half maximum of the rocking curve was determined to be 43.2 arcsec, indicating a high level of crystallinity in the heteroepitaxy film. The growth rate was calculated as 13.22 nm min−1 through the use of cross-section scanning electron microscope measurements. Additionally, the bandgap of the transparent film was determined to be 5.10 eV through transmittance spectra analysis. The high quality, wide bandgap heteroepitaxy α-Ga2O3 thin film described in this study represents a significant step forward in the preparation of high power and optoelectronic devices.

A low-density cellulose rich new natural fiber extracted from the bark of jack tree branches and its characterizations

The demand of natural cellulosic fibers has been increasing day by day due to their versatile uses and eco-friendly nature. The reason behind this demand is due to some unique properties of natural fibers that are suitable for several fibrous applications such as in composite, textile, nano-materials, conductive carbon, biomaterials etc. In this study, a new natural cellulosic fiber is extracted from the bark of the jack tree branches by water retting process. The fiber is characterized by standard methods. The result of the chemical compositions of the fiber shows that it contains α-cellulose 79.32%, hemicellulose 8.01%, lignin 6.77%, ash 3.58% and extractives 2.32%. XRD analysis reveals its high level of crystallinity (86%) and the microfibrillar angle (MFA) calculated from the XRD data is found −29°. The FTIR analysis confirms the presence of expected functional groups. Thermogravimetric analysis (TGA) and the derivative thermogravimetric (DTG) reveal its good thermal stability and the maximum degradation occurred at 358 °C for the degradation of the α-cellulose. The density of the fiber is found 1.05 g/cc, which is lower compared to many other known natural fibers. All these properties of this new fiber are suitable for several sophisticated fibrous applications such as reinforcement in composite, textile, cellulose nano-materials, activated or conductive carbon, biomaterials etc.

A Micro Mid‐Infrared Spectroscopic Study of Chang’e‐5 Sample

AbstractThe Chang’e‐5 (CE‐5) mission has successfully returned samples from a site that is much younger than the sites of all previous lunar sampling missions. Sample analysis results reported so far have revealed a more complex sampling area than previously thought, casting uncertainties over the interpretation of remote sensing spectral data and the U and Th abundance derived from the orbital data. Laboratory spectral measurement of the returned samples can serve as validation of remote sensing observations and thus help refine our understanding of the geological evolution of the landing region. In this study we report detailed micro mid‐infrared (MIR) spectral characteristics of individual soil grains of CE‐5 samples. The spectral analysis results show that the CE‐5 olivine grains have low Fo (molar Mg/[Mg + Fe] × 100) consistent with previous studies, indicating a Fe‐rich source region of the mantle or a highly evolved magma. These olivine grains show high level of crystallinity, implying low degree of space weathering. Most of the CE‐5 glasses analyzed are spectrally consistent with mare impact glasses, despite that a few of them may have a volcanic origin. These laboratory spectral analysis of CE‐5 samples in the MIR wavelengths at a micro scale, together with the derived MIR optical constants of the olivine, pyroxene, plagioclase, and glass grains, provide important input for the modeling and interpretation of thermal remote sensing data of the Moon.

Novel backbone modified polyetheretherketone (PEEK) grades for powder bed fusion with enhanced elongation at break

This study presents a new family of backbone modified polyetheretherketone (PEEK) grades in the powder bed fusion (PBF) process, coded as PAEK1 and PAEK2, with the same chemical structure but different molecular weights. By incorporating polyetherbiphenyletherketone (PEDEK) comonomer, the optimal powder bed temperature of the new grades could be reduced to 290 °C, approximately 40 °C lower than that of PEEK. The underlying crystallisation kinetics in the PBF process was investigated by replicating the in-process temperature profiles using a flash differential scanning calorimetry (DSC) machine. This method enabled monitoring of the development of crystallisation during the process and at different deposition thicknesses. The results confirmed that the PAEK2 grade with a higher molecular weight is slower crystallising. A significant part of the crystallisation of PAEK2 was found taking place in the later stage of the printing process, i.e. the free cooling stage. This leads to a better particle coalescence and enhanced elongation, a feature previously difficult to obtain in the PBF process. The PBF PAEK2 tensile bars achieved a significant increase in mechanical performance with an outstanding 13% in elongation, reaching its yielding point. The data supports that PAEK2 is the first high temperature polymer grade in the PBF process to match its bulk mechanical properties while maintaining a high level of crystallinity in the printed parts. • PAEK2 is the first PAEK grade recording high elongation with high crystallinity in PBF. • PEEK/PEDEK copolymer has a lower melting temperature with a high Tg. • The high molecular weight of the PAEK2 grade leads to a slow crystallising speed. • The cooling temperature profiles of the EOS P800 system was replicated with flash DSC. • This study provides insight into designing dedicated polymers for the PBF process.

The Characteristics and Potency of Limestone-based carbonate hydroxyapatite to Viability and Proliferation of Human Umbilical Cord Mesenchymal Stem Cell

Background: Limestone primarily consists of CaCO3 (calcium carbonate), which have a similarity to one of human bone component, hydroxyapatite (HA), an element of apatite group (Ca10(PO4)6(OH)2). There were several setbacks in the use of artificial hydroxyapatite in the bone repair process; one of them was its relatively higher crystallinity level compared to those of human bone apatite. The addition of carbonate element to hydroxyapatite could improve its characteristics, such as increasing the solubility, decreasing the crystallinity, and changing the morphology of the crystal. That caused carbonate hydroxyapatite is preferable to help in the bone repair process. Aims: This study aimed to find the effect of limestone-based CHA on viability and proliferation of hUMSCs, thus discovering the potential of CHA as a bone graft biomaterial candidate derived from limestone. Methods: This study used FTIR, EDX, and XRD assays to CHA powder sample derived from limestone found in Padalarang and Cirebon extracted by BBK. Two grams of the sample were placed in the sample holder and examined by computer software. EDX assay was conducted three times in three different points, and the means were recorded. In the XRD assay, a carbon tip was put to the sample holder to allow sample attachment. The recorded data was compared to JCPDS data. Toxicity and proliferation examination of CHA were conducted through MTT assay in human umbilical cord mesenchymal stem cell (hUCMSC) cell lines with four different doses: 50µg/ml, 25µg/ml, 12,5µg/ml, and 6,25µg/ml. Results: Limestone-based CA has hydroxyl (OH-), phosphate (PO42-), and carbonate (CO32-) functional groups. It has crystal particle formation and consists of O, Ca, and P elements. The result of the MTT assay showed limestone-based CHA is not toxic in all concentrations and has the proliferative ability. There were significant differences between the control and treatment groups. Conclusion: CHA has OH-, PO42-, and CO32- function group. It has crystal particle formation and O, Ca, and P elements as its composition, with a Ca/P ratio of 1,67. It shows no toxicity to hUCMSC in all doses and has the ability to stimulate hUCMSC proliferation.

Structural and Mechanical characteristic study of HPMC polymer composite films

Hydroxypropyl methylcellulose (HPMC) were extensively known material in packaging, agriculture, medicine, electrolytes in solid state batteries and other areas due to the exceptional biocompatibility and easy production, however shows lower mechanical behaviour. The current investigation was embraced to delineate the effect of potassium iodide (KI) on structural and mechanical properties of biopolymer electrolyte films grounded on Hydroxypropyl methylcellulose (HPMC). The liquidation of the salt into the polymer crowd is done by solution cast technique and the X – Ray diffraction (XRD) analyses were used to fix the structural properties of pristine HPMC and composite HPMC films. The crystallinity (Xc) was calculated, the pristine HPMC films shows high level of crystallinity. However improved amorphous spaces of HPMC polymer crowd were exposed in HPMC composite films. The addition of KI had a considerable impact on break elongation. In HPMC, KI showed good intercalation, and large concentrations of KI resulted in crater-like pits on the film surfaces. Reductions in the tensile strength and elastic modulus along with an increase in elongation were noticed in film integrated with KI.

Enhancement of organic solar cell efficiency by altering the zinc oxide photoanode nanostructure morphology

The current paper examines the effects of zinc oxide nanostructure configurations, as photo-anode formations of organic solar cells, on the performance of power conversion. To this end, some experiments were conducted during which a near band edge emission red shift of ~ 0.11 eV from nanoparticles to vertically oriented nano-rods was observed. This bandgap narrowing promotes transferring of photo-excited electrons towards the conduction band of photo-anode. A ~ 48% decrease in the deep level emission intensity revealed a smaller non-radiative waves emission due to lower level of crystal disorder. Using vertically oriented zinc oxide nanorods as photo-anodes, the photovoltaic efficiency of the organic solar cell improved considerably. The nano-rod-structured photo-anodes showed a 0.22 V rise in the open-circuit voltage, from 0.76 to 0.98 V, and a 2.08 times increment in the overall conversion performance, compared to the zinc oxide nanoparticle-structured photo-anodes. This superior performance is attributed to a greater chance of charge recombination and light-trapping in the cells, more efficient light absorption, and high level of crystallinity that grants easier electron mobility for vertically oriented zinc oxide nanorods. Moreover, a lower charge-transfer resistance (0.85 Ω) was achieved due to better electro-catalytic action for oxygen reduction for vertical nanorods compared to the other two zinc oxide configurations (1.62 Ω and 4.06 Ω). This boosted the cell performance by increasing the short-circuit current density (JSC). The fabricated solar cell may contribute to sustainable and environmentally friendly electricity generation process through reducing the consumption of non-renewable energy sources.

Insights into detailed hierarchical puncture-resistance for Bombyx mori silkworm cocoons

Silkworm cocoons illustrate excellent puncture-resistance performance after an insight into their layers while a clear understanding of the correlation between the excellent puncture property and the silk secondary structure is still lacking. Herein, we peeled silkworm cocoon into eight layers, and a combination of examination techniques including scanning electron microscopy, tensile mechanical test, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction were applied to figure out the morphologies (surface and cross-section view), mechanical properties, secondary structure, the content of β-sheet, and crystallinity of each layer's fibroin after degumming. The results indicated that the fifth layer offers a higher level of puncture-resistance than the other layers except for the eighth layer. Additionally, a high content level of β-sheet structure and high crystallinity gives rise to the high puncture strength as for hierarchical silk fibers. In general, the new finding holds great potential inspiration for the design of puncture-resistant composites.

II-VI Organic-Inorganic Hybrid Nanostructures with Greatly Enhanced Optoelectronic Properties, Perfectly Ordered Structures, and Shelf Stability of Over 15 Years.

Organic-inorganic hybrids may offer material properties not available from their inorganic components. However, they are typically less stable and disordered. Long-term stability study of the hybrid materials, over the anticipated lifespan of a real-world electronic device, is practically nonexistent. Disordering, prevalent in most nanostructure assemblies, is a prominent adversary to quantum coherence. A family of perfectly ordered II-VI-based hybrid nanostructures has been shown to possess many unusual properties and potential applications. Here, using a prototype structure β-ZnTe(en)0.5-a hybrid superlattice-and applying an array of optical, structural, surface, thermal, and electrical characterization techniques, in conjunction with density-functional theory calculations, we have performed a comprehensive and correlative study of the crystalline quality, structural degradation, electronic, optical, and transport properties on samples from over 15 years old to the recently synthesized. The findings show that not only do they exhibit an exceptionally high level of crystallinity in both macroscopic and microscopic scale, comparable to high-quality binary semiconductors; and greatly enhanced material properties, compared to those of the inorganic constituents; but also, some of them over 15 years old remain as good in structure and property as freshly made ones. This study reveals (1) what level of structural perfectness is achievable in a complex organic-inorganic hybrid structure or a man-made superlattice, suggesting a nontraditional strategy to make periodically stacked heterostructures with abrupt interfaces; and (2) how the stability of a hybrid material is affected differently by its intrinsic attributes, primarily formation energy, and extrinsic factors, such as surface and defects. By correlating the rarely found long-term stability with the calculated relatively large formation energy of β-ZnTe(en)0.5 and contrasting with the case of hybrid perovskite, this work illustrates that formation energy can serve as an effective screening parameter for the long-term stability potential of hybrid materials. The results of the prototype II-VI hybrid structures will, on one hand, inspire directions for future exploration of the hybrid materials, and, on the other hand, provide metrics for assessing the structural perfectness and long-term stability of the hybrid materials.

Recent Advances and Applications of Bacterial Cellulose in Biomedicine.

Bacterial cellulose (BC) is an extracellular polymer produced by Komagateibacter xylinus, which has been shown to possess a multitude of properties, which makes it innately useful as a next-generation biopolymer. The structure of BC is comprised of glucose monomer units polymerised by cellulose synthase in β-1-4 glucan chains which form uniaxially orientated BC fibril bundles which measure 3–8 nm in diameter. BC is chemically identical to vegetal cellulose. However, when BC is compared with other natural or synthetic analogues, it shows a much higher performance in biomedical applications, potable treatment, nano-filters and functional applications. The main reason for this superiority is due to the high level of chemical purity, nano-fibrillar matrix and crystallinity. Upon using BC as a carrier or scaffold with other materials, unique and novel characteristics can be observed, which are all relatable to the features of BC. These properties, which include high tensile strength, high water holding capabilities and microfibrillar matrices, coupled with the overall physicochemical assets of bacterial cellulose makes it an ideal candidate for further scientific research into biopolymer development. This review thoroughly explores several areas in which BC is being investigated, ranging from biomedical applications to electronic applications, with a focus on the use as a next-generation wound dressing. The purpose of this review is to consolidate and discuss the most recent advancements in the applications of bacterial cellulose, primarily in biomedicine, but also in biotechnology.

Characterization of polyaniline/polystyrene blends prepared by three different methods

A preparation and characterization of mixtures consisting of conductive polyaniline dispersed in polystyrene (PS) matrix are described. PANI was obtained by interfacial oxidative polymerization of aniline in the presence of sulfosalicylic acid, giving the protonated form the oxidation state of emeraldine (PANI-SSA). PS was synthesized by emulsion polymerization in the presence of sodium dodecyl sulfonic (SDS) as an emulsifier. Three methods were used for the preparation of PANI-SSA/PS mixtures: (1) green in-situ polymerization of aniline in the presence of SSA as a protonating agent and ammonium persulfate ((NH4)2S2O8 as an oxidant (Method I); (2) mixing PS with PANI-SSA dissolved in sulphuric acid at the temperature of 150 °C (Method II); and (3) mixing PS dissolved in dichloromethane (DCM) with PANI-SSA at room temperature (Method III). The prepared mixtures of different PANI-SSA content were characterized by FTIR, TGA, XRD and by electrical conductivity measurements. Mixing at high temperature (Method II) led to the formation of sulfonated polystyrene (PSS) or even three dimensional resins (through cross-linking of PSS) in which highly crystalline PANI particles were dispersed. The nanocomposites PS/PANI were elaborated by green in situ chemical polymerization (Method I) and by mixing with heating in the presence of sulphuric acid (Method II) at room temperature in the presence of dichloromethane at various percentages of PANI (Method III). These realized samples reported a high degradation temperature of PS which confirm that the PANI may even improve an inflammation property of polystyrene. The obtained composites proved a semi-crystalline character with a high level of crystallinity and the electrical properties range between 10–3 and 10–4 S/cm. These concepts are promising for the antistatic domain and charge dissipation domain.

Synthesis of Stable Thiazole-Linked Covalent Organic Frameworks via a Multicomponent Reaction

The development of robust synthetic routes to stable covalent organic frameworks (COFs) is important to broaden the range of applications for these materials. We report here a simple and efficient three-component assembly reaction between readily available aldehydes, amines, and elemental sulfur via a C-H functionalization and oxidative annulation under transition-metal-free conditions. Five thiazole-linked COFs (TZ-COFs) were synthesized using this method. These materials showed high levels of crystallinity, high specific surface areas, and excellent physicochemical stability. The photocatalytic applications of TZ-COFs were investigated, and TZ-COF-4 gave high sacrificial hydrogen evolution rates from water (up to 4296 μmol h-1 g-1 under visible light irradiation) coupled with high stability and recyclability, with sustained hydrogen evolution for 50 h.

SYNTHESIS AND CHARACTERIZATION OF STRUCTURAL NANOCOMPOSITE TITANIUM DIOXIDE COPPER-DOPED USING THE IMPREGNATION METHOD

Nanocomposite Titanium Dioxide (TiO2) doped Copper (Cu), Cu-TiO2 is synthesized by the impregnation method. This study aims to determine the effect of adding Cu to the TiO2 structure. 1, 3, and 5 Cu with% TiO2 dissolved in 50 ml of deionized water, and 3 grams of TiO2 added. The compound is then stirred for 2 hours at 900C and dried in an oven at 1100C for 30 minutes. Drying samples were calcined at 5000C for 3 hours. Cu-TiO2 nanocomposites were characterized by XRD, SEM-EDX Mapping, and FTIR. The XRD analysis results show that Cu-TiO2 nanocomposite has a high level of crystallinity and has an anatase phase structure. The size of TiO2 crystals decreased with Cu doping and increased from 49.66 nm to 49.68 nm, with an increase in the composition of the doping mass of Cu. The SEM-EDX Mapping results show that all samples tend to clot, and Cu dopants evenly distributed on the surface of TiO2. FTIR analysis explained the presence of hydroxyl ions in the sample marked with the appearance of the absorption peak at 1658.78 cm-1 associated with -OH bending of Ti-OH.

N-Heterocyclic Carbenes for the Self-Assembly of Thin and Highly Insulating Monolayers with High Quality and Stability.

As an organic nanostructure, self-assembled monolayers (SAMs) play a central role in many aspects of nanotechnology, including molecular electronics. In this work, we show that SAMs based on N-heterocyclic carbenes on a Au(111) substrate offer a high level of crystallinity and also exhibit the highest possible packing density. As a result of this structural optimization, defect concentrations were reduced by 2-3 orders of magnitude and thermal stability was ∼100 K higher than those of any other SAMs on Au. The conductivity of these SAMs is ∼4 orders of magnitude lower than that of standard alkanethiols of comparable length, which together with very low defect concentration and high thermal stability makes them a highly interesting material for potential application in organic thin film transistors. The self-assembly of such dense, highly crystalline, and notably stable structures is associated with strong C-Au bonding and the rational design of assembled molecules, resulting in the high mobility of both adsorbate and substrate atoms, as confirmed by the size of the molecular domains and the adsorbate-driven modification of the Au(111) substrate, respectively.