Acetone Suspension Research Articles

EVALUATING ACETONE AND METHANOL FOR ELECTROPHORETIC DEPOSITION OF SS 316L COATED WITH HYDROXYAPATITE/MULTIWALLED CARBON NANOTUBES DENTAL IMPLANTS: A FOCUS ON CORROSION RESISTANCE

Dental implants offer a reliable solution for replacing damaged tooth roots. This research investigates the comparative performance of acetone and methanol as suspension media in the fabrication of stainless steel type 316L-based dental implants using the Electrophoretic Deposition (EPD) method, a technique known for its simplicity and cost-effectiveness. Voltage variations of 20V, 30V, and 40V were applied to both acetone and methanol suspensions for a duration of 20 minutes. The morphology of the Hydroxyapatite/Multiwalled Carbon Nanotube (HA/MWCNT) coatings was meticulously characterized using Scanning Electron Microscopy (SEM). Corrosion resistance was evaluated through Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) techniques. Remarkably, at 30V, a homogeneous and crack-free coating was achieved, demonstrating superior corrosion resistance. This was further corroborated by the resistance values of 23.891 Ω and 114.990 Ω for the acetone and methanol samples, respectively. Additionally, the corrosion rates of 0.075 (mmpy) and 0.0004 (mmpy) for the acetone and methanol samples further emphasized the superiority of methanol as a suspension medium. These findings unequivocally establish methanol as the optimal choice for achieving superior deposition quality and corrosion resistance in the context of the EPD method for stainless steel type 316L-based dental implants.

Solvent effect on the NO2 sensing properties of multi-walled carbon nanotubes

This article is devoted to the investigation of the influence of the solvent on sensing properties, such as response and recovery rate, of chemiresistive gas sensors. Multi-walled carbon nanotubes were used as an active material for the sensors. The initial material was investigated by scanning electron spectroscopy and transmission electron microscopy, low-temperature nitrogen adsorption, Raman spectroscopy, and X-ray diffraction. The active material was produced by drop casting. Different polar solvents (acetone and ethanol) were used for suspension preparation. Textolite with copper contacts on the edges of one side was used as a sensor substrate. The gas sensing properties (the response and the recovery time) were investigated in the range of 100–500 ppm NO2 at room temperature. The films made using different solvent suspensions showed high sensitivity and rapid recovery rate to nitrogen dioxide. It was found that the method of film preparation has an effect on the measured sensing properties. The films prepared using different suspensions possessed different properties: the film made from the acetone suspension had the response values from 8.49% to 20.26%, and the recovery values from 0.06%/min to 0.16%/min. The response of the film made from the ethanol suspension increased , being from 12.25% to 23.63%; the recovery rate were also increased (from 0.19%/min to 0.39%/min).

Transport Properties of Natural and Artificial Smart Fabrics Impregnated by Graphite Nanomaterial Stacks.

In this work, we studied the transport properties (thermal and electrical conductivity) of smart fabric materials treated with graphite nanomaterial stacks–acetone suspensions. An innovative and easy method to produce graphite nanomaterial stacks–acetone-based formulations, starting from a low-cost expandable graphite, is proposed. An original, economical, fast, and easy method to increase the thermal and electrical conductivity of textile materials was also employed for the first time. The proposed method allows the impregnation of smart fabric materials, avoiding pre-coating of the fibers, thus reducing costs and processing time, while obtaining a great increase in the transport properties. Two kinds of textiles, cotton and Lycra®, were selected as they represent the most used natural and artificial fabrics, respectively. The impact of the dimensions of the produced graphite nanomaterial stacks–acetone-based suspensions on both the uniformity of the treatment and the transport properties of the selected textile materials was accurately evaluated using several experimental techniques. An empirical relationship between the two transport properties was also successfully identified. Finally, several theoretical models were applied to predict the transport properties of the developed smart fabric materials, evidencing a good agreement with the experimental data.

The synthesis and fluorescence detection properties of benzoquinone-based conjugated microporous/mesoporous polymers

The benzoquinone-based conjugated microporous/mesoporous polymers were synthesized through Sonogashira–Hagihara cross-coupling with tetrabromo-1,4-benzoquinone (TBrBQ) and 1,4-diethynylbenzene (DEB) by both solution polymerization (DBQP) and miniemulsion polymerization (DBQN). The Brunauer–Emmett–Teller (BET) surface areas of these polymers were 356 and 25 m2 g−1 and pore average diameter were concentrated at around 2.12 and 3.84 nm for DBQP and DBQN, respectively. The two dimensional π-conjugated polymer frameworks could be combined with permanent microporous/mesoporous, luminescent properties and abundant oxygen atoms in the skeleton. Fluorescence studies found that both DBQP and DPQN could be utilized as fluorescent chemosensors for picronitric acid (PA) in acetone suspension.

Mechanical behavior of a cellulose-reinforced scaffold in vascular tissue engineering

Scaffolds constitute an essential structural component in tissue engineering of a vascular substitute for small grafts by playing a significant role in integrating the overall tissue constructs. The microstructure and mechanical properties of such scaffolds are important parameters to promote further cellular activities and neo-tissue development. Cellulose nanowhiskers (CNWs), an abundant, biocompatible material, could potentially constitute an acceptable candidate in scaffolding of a tissue-engineered vessel. Inspired by the advantages of cellulose and its derivatives, we have designed a biomaterial comprising CNWs embedded in a matrix of cellulose acetate propionate to fabricate a fully bio-based scaffold. To ensure uniform distribution, CNWs were delicately extracted from a multi-stage process and dispersed in an acetone suspension prior to the composite fabrication. Comparable to carbon nanotubes or kevlar, CNWs impart significant strength and directional rigidity even at 0.2 wt% and almost double that at only 3.0 wt%. To ensure the accuracy of our experimental data and to predict the unusual reinforcing effect of CNWs in a cellulose-based composite, homogenization schemes such as the mean field approach and the percolation technique were also investigated. Based on these comparisons, the tendency of CNWs to interconnect with one another through strong hydrogen bonding confirmed the formation of a three-dimensional rigid percolating network, fact which imparted an excellent mechanical stability to the entire structure at such low filler contents. Hence, our fibrous porous microstructure with improved mechanical properties could introduce a potential scaffold to withstand the physiological pressure and to mimic the profile features of native extracellular matrix in a human vessel. We believe that our nanohybrid design not only could expand the biomedical applications of renewable cellulose-based materials but also could provide a potential scaffold candidate in tissue engineering of small diameter grafts.

Synthesis of Pb(Mg1/3Nb2/3)O3 by Self‐Assembled Colloidal Aggregates

We developed a new, simple method to prepare pure perovskite Pb(Mg1/3Nb2/3)O3 (PMN) from an aqueous suspension in a single annealing step. In this synthesis it is crucial to suppress the reaction between PbO and Nb2O5, which leads to secondary pyrochlore PbxNbyOz phases. Our method is based on the designed arrangement of particles of the starting compounds. The self‐assembly of the colloidal aggregates was governed by particle surface charge, which was adjusted by the suspension pH. At pH below 11.8 particle–particle interactions lead to close contacts between lead oxide and niobium oxide particles in the suspension as well as in the dried powders, whereas at pH above 11.8 close contacts between lead and niobium oxide particles are avoided. The suspensions of the starting powders were prepared at pH 10.0, 11.4, 12.5, and in acetone. After heating of the dried suspension with the pH set at 12.5 at 900°C, a pure perovskite PMN powder was obtained. On the contrary, the powders prepared from the pH 11.4, 10.0, and acetone suspensions still contained the detrimental pyrochlore phase after heating at 900°C. The properties of the ceramics prepared from the pH 12.5 suspension are superior in comparison with the other samples.

Fractal dimension and surface topography on the diamond deposition of seeded WC–Co substrates

Diamond thin films were deposited on WC–Co substrates by hot filament chemical vapor deposition to improve the tribological performance. The influence of the substrate surface topography was found to play an important role during the nucleation stage and the later growth rate as well. In this study, we systematically investigated the relation between substrate surface irregularity, which was evaluated by fractal dimension as well as statistical roughness parameters and the quality of the later deposited diamond film. Preseeding processes, in diamond acetone suspensions with two particle diameters, by supersonic vibrator were also implemented to investigate the effect of particular size on diamond nucleation. The original surfaces were measured with a stylus profiler and contact-mode atomic force microscopy. The diamond deposited substrates were examined by scanning electron microscopy, x-ray diffractometry, Raman spectroscopy, and Rockwell-C indentation to study substrate topography, crystalline structure of the coating, the composition of diamond films, and adhesion between deposited layers and substrates, respectively. The synergetic influence of the substrate’s fractal dimension and the particular size of pre-seeding diamond suspension were studied and addressed. The deposited film of a WC–Co substrate with higher surface fractal dimension (>2.50), preseeded by fine diamond suspension (4–12 nm particle size) in advance, has a high diamond-rich composition and adhesion strength.

Carbon nanostructures from Fe–C nanocomposites by activated CVD methods

AbstractIron‐based core‐shell nanoparticles can present interesting catalytic properties for the growth of carbon nanostructures. We report the synthesis of various carbon nanostructures using activated chemical vapour deposition methods. These structures were analysed by Scanning Electon Microscopy (SEM) and Raman spectroscopy. Laser pyrolysis technique was used for synthesis of less than 10 nm diameter Fe‐C core‐shell catalyst nanoparticles. Acetone suspensions of Fe‐C nanoparticles were drop‐casted or spin coated onto Si(100) substrates. The consequence of hydrogen selective etching of these nanocomposites at 550 °C, followed by a treatment with a mixture of H2 and C2H2 at 700 °C (both in the presence of hot filaments) was the growth of corrugated ribbons and decorated or distorted carbon nanotubes/nanofibers. Round agglomerate nanoparticles and long and very thin nanotubes were observed on the substrates edges (protected from direct etching). By adding in similar conditions a glow discharge plasma to hot filaments, the resulted deposits contain oriented nanotubes. Due to the implication of the electric field, the presence of both plasma and hot wires seems to significantly change the specific growth conditions of carbon nanostructures towards those resulted when only incandescent filaments were used (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Microfibrillated cellulose/cellulose acetate composites: Effect of surface treatment

AbstractMicrofibrillated cellulose (MFC), which consists of a web‐like array of cellulose fibrils having a diameter in the range of 10–100 nm, was incorporated into a cellulose acetate (CA) matrix to form a totally biobased structural composite. Untreated and a 3‐aminopropyltriethoxysilane (APS) surface treated MFC was combined with a CA matrix by film casting from an acetone suspension. The effectiveness of the surface treatment was determined by infrared spectroscopy and X‐ray photoelectron spectroscopy. The Young's moduli of APS treated MFC composite films increase with increasing MFC content from 1.9 GPa for the CA to 4.1 GPa at 7.5 wt % of MFC, which is more than doubled. The tensile strength of the composite film increases to a maximum of 63.5 MPa at 2.5 wt % compared to the CA which has a value of 38 MPa. The thermal stability of composites with treated MFC is also better than the untreated MFC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 153–161, 2010

Model Ziegler-Type Hydrogenation Catalyst Precursors, [(1,5-COD)M(μ-O2C8H15)]2 (M = Ir and Rh): Synthesis, Characterization, and Demonstration of Catalytic Activity En Route to Identifying the True Industrial Hydrogenation Catalysts

The compounds [(1,5-COD)M(mu-O2C8H15)]2 (COD = cyclooctadiene, M = Ir (1) or Rh (2), O2C8H15 = 2-ethylhexanoate) were synthesized by addition of Bu3NH(2-ethylhexanoate) or Na(2-ethylhexanoate) to acetone suspensions of [(1,5-COD)Ir(mu-Cl)]2 or [(1,5-COD)Rh(mu-Cl)]2, respectively. The synthesis of such well-defined second and third row model precursors is key to determining the true nature of commercial Ziegler-type hydrogenation catalysts (i.e., catalysts made from the combination of a non-zerovalent, group 8-10 transition metal precatalyst and a trialkylaluminum cocatalyst), an unsolved, approximately 40 year old problem. The characterizations of 1 and 2 were accomplished by elemental analysis, melting point, FAB-MS, FT-IR, UV-vis, NMR spectroscopy, and single crystal X-ray diffraction. The complexes, C32H54Ir2O4 and C32H54O4Rh2, are isostructural: monoclinic, P2(1)/n, Z = 4. The lattice constants for 1 are a = 15.7748(5) A, b = 9.8962(3) A, c = 20.8847(7) A, beta = 108.408(2) degrees. The lattice constants for 2 are a = 15.7608(4) A, b = 9.9032(3) A, c = 20.8259(5) A, beta = 108.527(1) degrees. Complexes 1 and 2 are dimeric, bridged by the 2-ethylhexanoates, and with one 1,5-COD ligand bound to each metal. The formally 16 electron metal atoms are in square ligand planes with dihedral angles between the planes of 56.5 degrees for 1 and 58.1 degrees for 2. The M-M distances of 3.2776(2) and 3.3390(4) A for 1 and 2, respectively, fall in the range of similar structures thought to have some M-M interaction despite the lack of a formal M-M bond. Demonstration that active Ziegler-type hydrogenation catalysts are made when 1 or 2 combine with AlEt3 is provided, results that open the door to the use of 1 and 2 as well-defined third and second row congeners, respectively, of Ziegler-type hydrogenation catalysts. These compounds have proven important in addressing the previously unsolved problem of the true nature of the catalyst in industrial Ziegler-type hydrogenation catalyst systems; their high yield synthesis and unequivocal characterization reported herein are the necessary first steps of that work.

Preparation and evaluation of itraconazole dihydrochloride for the solubility and dissolution rate enhancement

The purpose of this work was to explore the feasibility of preparing itraconazole hydrochloride to improve the solubility and dissolution rate. Itraconazole dihydrochloride was synthesized by bubbling anhydrous hydrogen chloride gas into the acetone suspension of itraconazole. Results of the elementary analysis gave the molecular formula of C 35H 38Cl 2N 8O 4·2HCl and its structure was confirmed by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Powder X-Ray diffraction (PXRD) suggested that a new crystalline form of the salt was formed. The morphology and mean size distribution study by scanning electron microscopy (SEM) and dynamic light scattering (DLS) confirmed that the salt was dispersable nanoparticle aggregation. Aqueous solubility measurements showed that the solubility of the salt, its 1:1, 1:2 and 1:3 (w/w) physical mixtures with beta-cyclodextrin (β-CD) was 6, 99, 236 and 388 times greater than itraconazole. More than 94% of itraconazole was dissolved out of the salt/β-CD 1/3 physical mixture after 60 min. The stability studies indicated that the physical mixture remained stable for 24 months in assay, the related substances and dissolution. Based on the present results, it is concluded that hydrochloride formation can significantly increase solubility and dissolution rate of itraconazole, and the formulation of itraconazole dihydrochloride/β-CD (1/3) would be an environment-friendly, economic and practical alternative to the commercially available itraconazole capsules (Sporanox ®).

Fabrication of functionally graded 3A/5A zeolites by electrophoretic deposition

Functionally graded zeolites of molecular sieve type 3A and 5A are deposited by electrophoretic deposition (EPD) from acetone suspension with 8% volume concentration of n-butylamine as particle charging agent. The EPD characteristics of both 3A and 5A suspensions are studied. Functionally graded zeolite 3A/5A deposits are obtained at 200 V DC. Energy dispersive X-ray dispersion (EDX) analysis results confirm the graded structure. The deposited zeolites are also analysed by scanning electron microscopy (SEM). The factors influencing the deposition process are discussed.

Electrophoretic co-deposition of diamond/borosilicate glass composite coatings

Composite coatings made of diamond powders and borosilicate glass have been deposited on stainless steel substrates by electrophoretic co-deposition. Ethanol and acetone suspensions containing diamond powders of particle size 1–2 μm and borosilicate glass powders of size 0.1–0.5 μm were used. Electrophoretic deposition (EPD) parameters were optimized by a trial-and-error-approach. Microstructures of deposited and sintered coatings were investigated by XRD and SEM analysis. The results show that applied voltages up to 10 V led to thin and incomplete coatings. Voltages higher than 50 V resulted in uneven coatings with uncontrolled thickness and poor uniformity. The best results were achieved using ethanol suspensions. Smooth, uniform and dense coatings with diamond and glass particles distributed uniformly were obtained under applied voltages in the range of 30–50 V and a deposition time of 4 min. The concentration ratio of diamond to borosilicate glass in the composite coatings was in good correlation with the original ratio in suspension, thus control of the coating microstructure and composition is possible. During sintering at 900 °C, the glass particles softened; sintered by viscous flow and spread over the diamond particles surface. Thus a glass layer forms protecting the diamond from oxidization or graphitization and bonding the diamond particles together.

Water Versus Acetone Electrophoretic Deposition of Hydroxyapatite on 316L Stainless Steel

Hydroxyapatite (HAP) was electrophoretically deposited on 316L stainless steel in order to promote a bioactive surface. The effect of dispersing media (water and acetone), applied voltage and the deposition time on the deposit weight and microstructure of the coatings was evaluated. The deposition time was varied in the range of 1 to 900 s for water suspensions and 0.5 to 180 s for acetone suspensions. Suspensions were prepared by using HAP powder with an average particle size of 1.5 μm at a concentration of 1 % by weight. The deposition was performed under a direct current (DC) field of 400 to 1000 V for acetone suspensions and 5 to 50 V for water suspensions. The coatings were analyzed using scanning electron microscopy. The amount of hydroxyapatite on the surface of the metallic substrate was evaluated by determining the difference in weight of the samples, before and after the electrophoretic process. The stabilization of HAP particles in water was achieved using 1 % by weight of Dispex N40TM and 0.001M KCl. Under this condition the zeta potential of HAP in water suspension was –28 mV. Non additive was required in acetone suspensions. Dense, homogeneous and crack-free coatings of sub-micron particles (0.63 mg/cm2) were obtained by applying 5 V during 60 s in water suspensions. Above a DC field of 5 V the hydrolysis of water seriously difficulties the coatings formation. Homogeneous and crack-free coatings of sub-micron particles (1.45 mg/cm2) were also obtained in acetone suspensions applying 400 to 1000 V during 5 s. Lower voltages were not used with acetone suspensions due to its high resistivity.

EPD-Sintering of Hydroxyapatite, Porcelain and Wollastonite on 316L Stainless Steel

Hydroxyapatite, porcelain and wollastonite coatings on stainless steel 316L were produced by electrophoretic deposition (EPD) in ethanol and acetone using a voltage between 200 and 1000 V during 0.5 to 60 s. The particle size distribution of the starting suspension was 0.3 to 4.9 microns with an average size of 1.5 microns. The coatings were analyzed using scanning electron microscopy. The amount of ceramic material on the surface of the metallic samples was evaluated by determining their difference in weight before and after the electrophoretic deposition process. The conductivity and zeta potential of the dispersing media were also evaluated. Dense, homogeneous and crack-free green coatings were obtained. The deposition rate was higher by using acetone as dispersing media. The higher zeta potential and the lower viscosity were attributed to be the cause of the better electrophoretic deposition of the acetone and methanol ceramic suspensions. Submicron particle coatings were then sintered between 800 and 1000 C during 2 h. The sintered coatings presented a very homogeneous polycrystalline structure free of cracks. The results show that the application of high voltage during short periods of time is an effective method to obtain ceramic coatings with good sinterability.

Proteomic analysis of rice leaf, stem and root tissues during growth course

Rice proteins were isolated from leaf, stem and root tissues, harvesting at 1, 2, 4, 8 and 10 weeks after budding. Each tissue of each age was separately pulverized in liquid nitrogen, and the resulted tissue powders were suspended in 10% TCA-acetone and followed by acetone suspension to precipitate at low temperature, which resulted in the tissue-specific and age-specific protein mixture. The protein mixtures were separated by 2-DE using polyacrylamide gels (26 x 20 cm). The protein spots were identified by N-terminal sequence analysis and by MALDI and LC-MS/MS analyses after in-gel tryptic digestion. From a total of 4532 spots, 676 unique proteins were identified, of which 80 proteins (12%) were observed in all three tissues: leaf, stem and root. In addition, 45 (7%) were common in leaf and stem, 57 (8%) in stem and root, and 10 (2%) proteins in root and leaf. Also 141 unique proteins (21%) were observed only for leaf, 96 (14%) for stem, and 247 (36%) for root tissue. Proteins playing a role for photosynthesis and energy production were most abundant in leaf and stem, and those for cell defense were rich in roots.

PEG 첨가에 의한 YBCO 전착후막의 특성 향상

The electrophoretic deposition method using the suspension solution with additives under the electric potential was applied for the fabrication of YBCO superconductor wire. This method was able to simplify the fabrication facilities, and produce an uniform and dense thick film. To improve the critical current density of deposited films, the additive PEGs(Poly Ethylene Glycole) with the molecular weight of 600, 1000 and 3400 were used as chemical binders for the suspension solution. The organic additive (PEG) showed better effects to the properties of YBCO superconductor wire. The PEG improved the adhesion between superconductor particles and suppressed the crack on the surface, which enhanced the surface uniformity and density of YBCO deposited film. It was found that acetone suspension solution showed better deposition properties than the others. The samples fabricated in the solution with the additive, 8 vol.% of 1% PEG(1000), showed the highest critical current density measured as 2300∼2400 A/<TEX>$\textrm{cm}^2$</TEX> at 77 K, 0 T.

Fabrication of poly-Si thick films by electrophoreticdeposition

The electrophoresis of silicon particles in acetone, and the electrophoretic deposition of poly-silicon thick films are reported for the first time. The anodic deposition of Si particles was achieved by applying DC electric fields of ~100 V/cm between two electrodes soaked in a semistable acetone suspension. Uniform layers were reproducibly formed on gold, graphite and silicon wafer anodes (substrates). The technique was successfully applied on substrates of complicated shapes.

Electrophoretic deposition of MgO thick films from an acetone suspension

Mechanism and kinetics of electrophoretic deposition in an MgO/acetone cell were studied. Linear relations of the deposition yield with voltage applied, time and particle concentration was experimentally verified at both very low concentration levels (∼0.02 wt.%) and short deposition times (∼5 s). Deposition was constantly cathodic with a particle mobility of 2.5×10 −4cm 2/V.s. Results were similar for all substrate materials employed. An optimum voltage range for obtaining uniform and sufficiently adherent films was established. Scanning electron micrograph observations revealed each particle to be independent in both migration and deposition processes. Under clean conditions, finely porous MgO films were reproducibly formed in suspensions of low concentrations.

Preparation of YBCO superconducting thick film by electrophoresis

The thick films of YBa 2Cu 3O x (YBCO) superconductor were prepared by electrophoretic deposition, using pre-sintered YBCO powder dispersed in acetone solution. The alumina (Al 2O 3) ceramic plate, coated with Ag, was used as the cathode substrate and the stainless steel mesh electrode was used as the counter electrode in suspension for electrophoresis. The conditions of applied voltages and temperatures, contents of iodine additives, and deposition times for electrophoretic deposition of YBCO thick films were studied in detail. As a result, the optimum value of iodine content in acetone was 200 mg/l, the applied electrical potential for electrophoresis was 200–300 V for 10 mm electrode gap, and the content of YBCO powder was 10–20 g/l in acetone suspension solution. The critical temperature was determined at 91 K by AC susceptibility curve and the critical current density, J c, was measured by a four-point prove method at the value of 700 A/cm 2 deposited on the Ag coated Al 2O 3 substrate and 1456 A/cm 2 deposited on the Ag wire (77 K, 0 T).