Polished Stainless Steel Research Articles

Effect of Pyrolysis Temperature on Electrochemical Performance of SU-8 Photoresist Derived Carbon Films As Lithium Ion Battery Anode Material

Introduction Since last decade, SU-8 negative photoresist is considered as a precursor to yield glassy carbon that comprises short range crystallites.1,2 Owing to its advantages in terms of patterning and ability to fabricate 3-D carbon electrodes, SU-8 photoresist derived carbon has been demonstrated as potential anode materials for lithium ion battery.2,3 We recently reported the use of stainless steel (SS) wafer instead of Si wafer as a substrate for preparing SU-8 derived planar carbon films which exhibited excellent reversible capacity as compared to previous available reports.4 While preparing the carbon films from SU-8 on SS wafer, we carried out the two step pyrolysis at 900 °C.4 However the effect of varying the pyrolysis temperature on structural properties of carbon films derived and subsequently on electrochemical characteristics is yet to be studied. In this work, we pyrolyzed SU-8 films on SS wafer at four different temperatures in the range of 700 °C and 1000 °C. As-fabricated SU-8 derived carbon films were structurally characterized by XRD, Raman and CHNS analysis. Electrochemical performance of as-prepared carbon films were tested using galvanostatic charge discharge experiments at 37.2 mA/g current density and the specific capacities were correlated with the H/C ratio and crystalline structure. Experimental: SU-8 2005 was spin coated on single side polished SS wafer after drying at 150 °C on hot plate for 10 min. Thus obtained films were crosslinked using C-MEMS process, and process conditions were optimized for SS wafer. These films were then pyrolyzed in tubular furnace in presence of N2 atmosphere. As-prepared carbon films were then used as working electrode to study their electrochemical properties whereas lithium foil was used as a counter electrode. Glass microfiber filter soaked with LP-30 electrolyte was used as a separator. Results and discussions: XRD and Raman spectra as shown in Fig. 1a and 1b confirms that prepared carbon films are hard carbons and increase in pyrolysis temperature has no significant effect on their crystallinity. However, samples pyrolyzed at different temperature showed significant change in carbon content and H/C ratio as shown in Fig.1c. H/C ratio increased with decreasing temperature. Fig. 1d shows the cyclic performance of the samples at 0.1 C and between 0.01 -3V. Galvanostatic charge discharge experiments reveals that though reversible capacity decreases, cyclic stability and initial cycle coulombic efficiency increases with increasing temperature. This behavior can be attributed to decrease in hydrogen content and increase in radius of gyration due to rearrangement of graphene layers which results in improved alignment with neighboring layers with increasing temperature.5

Ultrafast laser beam shaping for material processing at imaging plane by geometric masks using a spatial light modulator

We have demonstrated an original ultrafast laser beam shaping technique for material processing using a spatial light modulator (SLM). Complicated and time-consuming diffraction far-field phase hologram calculations based on Fourier transformations are avoided, while simple and direct geometric masks are used to shape the incident beam at diffraction near-field. Various beam intensity shapes, such as square, triangle, ring and star, are obtained and then reconstructed at the imaging plane of an f-theta lens. The size of the shaped beam is approximately 20µm, which is comparable to the beam waist at the focal plane. A polished stainless steel sample is machined by the shaped beam at the imaging plane. The shape of the ablation footprint well matches the beam shape.

Level monitoring system with pulsating sensor--application to online level monitoring of dashpots in a fast breeder reactor.

An innovative continuous type liquid level monitoring system constructed by using a new class of sensor, viz., pulsating sensor, is presented. This device is of industrial grade and it is exclusively used for level monitoring of any non conducting liquid. This instrument of unique design is suitable for high resolution online monitoring of oil level in dashpots of a sodium-cooled fast breeder reactor. The sensing probe is of capacitance type robust probe consisting of a number of rectangular mirror polished stainless steel (SS-304) plates separated with uniform gaps. The performance of this novel instrument has been thoroughly investigated. The precision, sensitivity, response time, and the lowest detection limit in measurement using this device are <0.01 mm, ∼100 Hz/mm, ∼1 s, and ∼0.03 mm, respectively. The influence of temperature on liquid level is studied and the temperature compensation is provided in the instrument. The instrument qualified all recommended tests, such as environmental, electromagnetic interference and electromagnetic compatibility, and seismic tests prior to its deployment in nuclear reactor. With the evolution of this level measurement approach, it is possible to provide dashpot oil level sensors in fast breeder reactor for the first time for continuous measurement of oil level in dashpots of Control & Safety Rod Drive Mechanism during reactor operation.

Polarisation-dependent generation of fs-laser induced periodic surface structures

The formation of laser induced periodic surface structures (LIPPS) was investigated on polished stainless steel surfaces under irradiation with fs-laser pulses characterised by a pulse duration τ=300fs, a laser wavelength λ=1025nm, a repetition frequency frep=250Hz and a laser fluence F=1J/cm2. For this purpose line scans with a scanning velocity v=0.5mm/s were performed in air environment at normal incidence utilising a well-defined temporal control of the electrical field vector. The generated surface structures were characterised by optical microscopy, by scanning electron microscopy and by atomic force microscopy in combination with Fourier transformation. The results reveal the formation of a homogenous and highly periodic surface pattern of ripples with a period Λexp≈925nm aligned perpendicular to the incident electric field vector for static linear polarisation states. Utilising a motor-driven rotation device it was demonstrated that a continuously rotating electric field vector allows to transfer the originally well-ordered periodic ripples into tailored disordered surface structures that could be of particular interest for e.g. absorbing surfaces, plasmonic enhanced optoelectronic devices and biomedical applications.

Accurate determination of the total hemispherical emittance and solar absorptance of opaque surfaces at elevated temperatures

In many applications such as solar power conversion technologies, radiative heat transfer plays a significant role in the energy balance. For accurate performance predictions of solar power conversion devices the total hemispherical emittance and solar absorptance of surfaces need to be known with high accuracy. Often times the emittance of a surface is calculated from indirect spectral bidirectional or directional-hemispherical reflection measurements at room temperature which can significantly underestimate the total hemispherical emittance. Here, we report a simple steady-state calorimetric method to directly measure the total hemispherical emittance of opaque surfaces at elevated temperatures with a maximum experimental uncertainty of 5%. The method is further expanded to directly measure the solar absorptance of the surface at elevated temperature using a solar simulator. We show experimental total hemispherical emittance and solar absoprtance results for various surfaces such as machine polished copper and stainless steel and several spectrally selective solar absorbers. We describe a methodology to characterize solar absorbers and apply it to a cermet-based spectrally selective solar absorber.

Effect of splat morphology on the microstructure and dielectric properties of plasma sprayed barium titanate films

In the thermal spray process, the film is built up by impingement of molten droplets onto substrate. Splats are created by flattening and spreading of the impacting droplets. Splat morphology can determine the microstructure, physical and mechanical properties of the coating. In this study, BaTiO3 films were deposited onto a mirror polished stainless steel substrates kept at three different temperatures (25, 300 and 600°C). At the elevated temperatures, the substrate surface topography and the desorbtion of adsorbates and condensate at the substrate surface are two important factors which change the morphology of the individual splats, from splash morphology to disk-like shape. Splat morphology can determine deposit microstructure and improve the coating properties. The morphology of individual splats and the films were studied using scanning electron microscopy. Phase formation of the films was analyzed by X-ray diffraction. The surface topography of the substrates with different temperatures was analyzed using atomic force microscopy. Furthermore, X-ray photoelectron spectroscopy was performed to determine the chemical compositions of the surface substrate. Results indicated that the porosity in the film produced at room temperature was higher than that in the film deposited on the heated substrates. Also, the dielectric coefficient of the films was increased by decreasing the common defects from 120 to 505 for film deposited on as-received and heated substrates, respectively.

Tribology of composites produced with recycled GFRP waste

Nowadays, is expected that for most materials to be environmentally friendly. Besides, waste from end-of-life products may be considered a secondary source of materials with an energetic advantage due to its high energy content. This paper deals with the study of friction and wear characteristics of Glass fibre-reinforced polymer (GFRP) composites with polyester/glass fiber (P/GF) waste as filler, replacing the widely used calcium carbonate (CaCO3). Polyester composites based on two or three components, using a combination of polyester, CaCO3, GF, and GF waste, were produced. Pin-on-disc sliding wear test was performed using a polished stainless steel counterface. Roughness, surface energy, and hardness of the composites were characterized before the tests. The GF content (15, 25, 35, and 50 wt.%), the sliding velocity (0.021 and 0.042 m/s), and the normal load (1, 5, and 10 N) were varied. Based on the experimental results, it was observed that the friction coefficient and wear rate were influenced by material composition, surface roughness and energy, adhesive, and abrasive contact mechanisms. P/GF composites having P/GF waste presented enhanced performance considering friction and wear in relation to those with CaCO3 in their composition.

Enhanced Thermal Stability of W‐Ni‐Al2O3 Cermet‐Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors

Solar thermal technologies such as solar hot water and concentrated solar power trough systems rely on spectrally selective solar absorbers. These solar absorbers are designed to efficiently absorb the sunlight while suppressing re‐emission of infrared radiation at elevated temperatures. Efforts for the development of such solar absorbers must not only be devoted to their spectral selectivity but also to their thermal stability for high temperature applications. Here, selective solar absorbers based on two cermet layers are fabricated on mechanically polished stainless steel substrates using a magnetron sputtering technique. The targeted operating temperature is 500–600 °C. A detrimental change in the morphology, phase, and optical properties is observed if the cermet layers are deposited on a stainless steel substrate with a thin nickel adhesion layer, which is due to the diffusion of iron atoms from the stainless steel into the cermet layer forming a FeWO4 phase. In order to improve thermal stability and reduce the infrared emittance, tungsten is found to be a good candidate for the infrared reflector layer due to its excellent thermal stability and low infrared emittance. A stable solar absorptance of ≈0.90 is demonstrated, with a total hemispherical emittance of 0.15 at 500 °C.

Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D.

An imaging system with a wide-angle tangential view of the full poloidal cross-section of the tokamak in simultaneous infrared and visible light has been installed on DIII-D. The optical train includes three polished stainless steel mirrors in vacuum, which view the tokamak through an aperture in the first mirror, similar to the design concept proposed for ITER. A dichroic beam splitter outside the vacuum separates visible and infrared (IR) light. Spatial calibration is accomplished by warping a CAD-rendered image to align with landmarks in a data image. The IR camera provides scrape-off layer heat flux profile deposition features in diverted and inner-wall-limited plasmas, such as heat flux reduction in pumped radiative divertor shots. Demonstration of the system to date includes observation of fast-ion losses to the outer wall during neutral beam injection, and shows reduced peak wall heat loading with disruption mitigation by injection of a massive gas puff.

Design, Constructand Performance Evaluation of a 2-Stage Parabolic through Solar Concentrator in Pathumthani

This research presents the design, construct and performance evaluation of a 2-stage parabolic trough solar concentrator (2-stage PTC). The primary stage was constructed of polished stainless steel (SUS 400) to form the primary stage parabolic reflector (1.489 m ×1.489 m size), the second stage was constructed of multi piece mirror to form the hyperbolic shape reflector (0.13 m×1.489 m). Black painted copper pipe in the size of inside diameters (27.2 mm) covered with glass tube was used as receiver. One axis Sun tracking system has been installed to track 2-stage PTC according to the direction of beam propagation of solar radiation. By using water as a heat transfer fluid its capability to heat transfer and load high temperature (100°C). The storage tank is fabricated with stainless steel of size 40 L. The experimental tests have been carried out in Faculty of Industrial Technology, Vallaya Alongkorn Rajabhat University Pathum Thani, Thailand climatic conditions (14.134°N, 100.611°E) during 5 selected days of the months May 2013. The performance of a 2-stage PTC was evaluated using outdoor experimental measurements including the useful heat gain, the thermal instantaneous efficiency and the energy gained by the water. The experimental results shown the maximum thermal efficiency was 23.43%, the optical efficiency was 76%, and the total geometrical concentration was 27.08X.

Photoresist Derived Carbon Films as High Capacity Anodes for Lithium Ion Battery

INTRODUCTION Hard carbons prepared by pyrolysis of various polymer precursors have been tested for lithium ion intercalation and were found having higher reversible capacities than that of graphite (1, 2). However the main disadvantage of using hard carbon as anode material for lithium ion battery is higher irreversible capacity due to absorption of lithium ions on the internal surface of nanopores formed by disordered single layer graphene sheets (3).Madou et al. used SU-8 photoresist to prepare carbon films on silicon wafer for lithium insertion (4). Their electrical characteristics were found similar to that of glassy carbon while their reversible capacity was measured to be ~ 220 mAh/g (5).In this study SU-8 photoresist derived carbon films were prepared on stainless steel (SS) wafer as substrates. The choice of SS wafer (resistivity: 73 µΩ-cm) as a substrate is more apt as the same is used in the commercial lithium ion battery. Galvanostatic charge discharge of assembled Swagelok cell within 0.01-3 V was performed to measure the lithium insertion capacities. EXPERIMENTAL SU-8 2005 (Microchem Corp., MA) was spin coated at 3000 rpm for 30 s on dehydrated single side polished SS substrates (MTI Corp., USA). After 10 min relaxation, films were soft baked at 950C for 2 min. After cooling to room temperature films were exposed to UV light followed by post exposure bake at 95 0C for 3 min to complete the crosslinking. Hard bake of samples was carried out at 1500C to reduce the internal residual stresses generated due to shrinkage during crosslinking.As-prepared SU-8 films were then carbonized at 9000C in the inert atmosphere using two step pyrolysis. Thus prepared SU-8 derived carbon film on SS and lithium foil (Sigma Aldrich) were used as working and counter electrode respectively. 1M solution of LiPF6in a 1:1 v/v mixture of ethylene carbonate and diethyl carbonate was used as an electrolyte and glass microfiber filter (Whatman Filters) was used as separator. Packed Swagelok cells were soaked for 12 h before Galvanostatic cycling at C/10 rate to measure intercalation capacity of SU-8 derived carbon films as anode. RESULTS Cyclic voltammetry Cyclic voltammogram recorded at 1 mV/s is shown in Fig.1a. Broad reduction peak at 0.5 V corresponds to reduction of passive layer formation by electrolyte decomposition and other reduction peak near 0 V corresponds to absorption of Li ions in hard carbon. Galvanostativc charge discharge cycling Galvanostatic discharge and charge cycles experiment was carried out at C/10 rate (Fig. 1b). Initial discharge capacity was very high compare to other cycles due to electrolyte decomposition voltage near to 0.4 V (6). Reversible capacity was found to be ~400mAh/g which was higher than that of graphite and also as reported earlier (5). Electrochemical impedance spectroscopy (EIS) Fig. 1c shows the Niyquist plot recorded under ac amplitude of 10 mV over the frequency range of 10 mHz-100 KHz.The charge transfer resistance was found to be less than half as compared to reported values (5) earlier that further suggests the superior performance of the designed architecture (SU-8 photoresist derived carbon on SS substrate).Fig.1 (a) Cyclic voltammetry of SU-8 derived carbon film on SS substrate; (b) Galvanostatic charge discharge curve for SU-8 derived carbon films on SS substrate at C/10 rate; (c) EIS plot for SU-8 derived carbon film after 10 charge/discharge cycles SUMMARY Photoresist (SU-8) derived carbon films were prepared on SS as substrates and then tested for lithium ion intercalation. Galvanostatic charge/discharge experiments shows higher reversible capacity (400 mAh/g) as compared to graphite and previous values reported. EIS measurements also supplement these findings that may be of potential use for anode materials for Lithium ion battery. REFERENCES 1. A. Piotrowska et al., J. Anal. Appl. Pyrolysis, 102, 1 (2013).2. T. Zheng et al., J. Electrochem. Soc., 142, 2581 (1995).3. Y. Liu et al., Carbon, 34, 193 (1996).4. B. Y. Park et al., J. Electrochem. Soc., 152, J136 (2005).5. G.T. Teixidor et al., J. Power Sources, 183, 730 (2008).6. S. Zhang et al., Electrochem. Solid State Lett., 4, A206 (2001).

Small-scale passive emission chamber for screening studies on monoterpene emission flux from the surface of wood-based indoor elements

Analysis of literature data published in the last few years leads to the conclusion that in the process of assessment of emission flux of organic compounds emitted from different types of equipment and finishing materials, new types of devices, among which small-scale passive emission chambers for the performance of in-situ research are designed and applied on a larger scale. These devices can be successfully used for the assessment of emission flux of organic compounds in any location of an apartment, with no interference with its normal exploitation.In the following article the possibility of application of a designed and constructed small-scale passive emission chamber for the evaluation of emission flux of organic compounds (mainly monoterpenes) emitted from the surface of wood-based material made of laminated chipboard has been presented. The emission chamber made from polished stainless steel of the inner volume of 3.65dm3 allows for the examination/assessment of emission flux from the surface of 452cm2. A diffusive passive sampler was installed inside of the small-scale chamber, which enables collecting samples of the analytes emitted from the examined surface of indoor material. The working time of the passive emission chamber equaled 300min.The results of preliminary studies show that, the constructed device can be successfully used for screening studies, related with the determination of emission flux of monoterpenes from any type of wood-based flat surface located indoors.

Observations and Mechanism of CaSO4Fouling on Hydrophobic Surfaces

Pool boiling of CaSO4 solution on prepared microscale and nanoscale hydrophobic titania–fluoroalkylsilane (TiO2–FPS) composite coatings on polished AISI304 stainless steel (SS) substrates was carried out to evaluate the antifouling behavior of these surfaces. Lower fouling resistance and looser, slender, and larger CaSO4 crystals on hydrophobic TiO2–FPS coatings were observed compared to those on the TiO2 coatings and SS surfaces. The colloidal interaction energies between crystalline particles and coated surfaces were analyzed by using the extended Dejaguin– Landau–Verwey–Overbeek (XDLVO) theories to explore the possible mechanism of inhibition of fouling. The results of the XDLVO analyses generally agree to the experimental observations. The Lewis acid–base component contributes most of the total XDLVO interaction energy. Low surface free energy and electron donor component of heat transfer surface lead to a low fouling resistance and a small initial deposition rate of CaSO4 fouling. On the basis of the...

Emissivity of silver and stainless steel from 80 K to 300 K: Application to ITER thermal shields

The emissivities of thermal shield mock-up samples for ITER have been measured at sample temperatures between 80K and 300K using an optical method employing a primary standard broadband detector. These thermal shields, made from SS304L stainless steel coated with silver, are designed to operate at 80K, protecting the superconducting magnet system of the ITER reactor from higher temperature regions. Our results show that the silver coating of the thermal shields can have an emissivity as low as 0.0035 at 80K, approximately ten times lower than the emissivity of the bare polished stainless steel plate. We demonstrate that the emissivity of different regions of a thermal shield assembly can be determined in a single measurement cycle, providing further emissivity data on the insulating spacer used to separate shield plates as well as emissivity data on a silver coating repair method. The temperature dependence of the emissivity for the silver coating agrees well with a theoretical estimate based on the Drude model including phonon and surface-assisted scattering.

Comparison of thermodynamic characteristics of desorption and ionization of silver halides from stainless steel and aluminum-based surfaces according to mass-spectrometry data

Differences in the energetic and kinetic characteristics of the ionization of silver halides from different surfaces are found with the use of mass spectrometry. Ionization of silver-halide clusters from the surface of a standard target made of polished stainless steel (Bruker) is studied in comparison to AMg-6 and Ad-0 aluminum-alloy materials. It is found that, despite the lower specific ionization energy, a rough surface strongly hampers the evaporation and desorption and, hence, lowers the efficiency of sublimation and desorption of a substance. In addition, a rough surface is characterized by irregular surface distribution of energy and uneven heating, which also lowers the efficiency of ionization. The surface geometry is found to affect the thermodynamics and kinetics of the formation and fragmentation of ions. On rough surfaces, the formation energies of ions are higher by a factor of 1.5–2 compared to those on polished surfaces and the spectrum of ions and energy ranges of their existence are much broader.

One-step hydrothermal preparation of TiO2/WO3 nanocomposite films on anodized stainless steel for photocatalytic degradation of organic pollutants

TiO2/WO3 nanocomposite film was deposited on anodized stainless steel by one step hydrothermal reaction. Polished stainless steel foil was anodized to form nanopore arrays on the surface that is favorable for the immobilization of photocatalyst. The TiO2/WO3 nanocomposite film prepared in 0.01mol/L (NH4)2TiF6 and 0.0066mol/L Na2WO4 solution at 120°C for 3h exhibits the maximum photocatalytic activity, which is five times higher than that of pure TiO2 film and eight times higher than that of pure WO3 film. As compared with the pure TiO2 film, the main absorption edge of the WO3/TiO2 nanocomposite film shifts toward visible region and the absorption intensity is obviously improved. The nanocomposite film has a preferable crystallinity of anatase TiO2 and the monoclinic WO3, as revealed by X-ray diffraction and X-ray photoelectron spectroscopy. Scanning electron microscopy images show that the nanocomposite film is homogenous in size distribution and uniform in morphology. The high resolution transmission electron microscopy images further demonstrate the formation of mixed crystal between WO3 and TiO2 nanoparticles. The excellent photocatalytic activity of the nanocomposite film should be attributed to the formation of heterojunction between TiO2 and WO3 nanoparticles that can facilitate the separation of photo-generated electron–hole pairs.

Initial adhesion of Listeria monocytogenes to fine polished stainless steel under flow conditions is determined by prior growth conditions

Listeria monocytogenes is a food-borne pathogen known to persist in food production environments, where it is able to attach and form biofilms, potentially contaminating food products ready for consumption. In this study the first step in the establishment of L. monocytogenes in a food-processing environment was examined, namely the initial adhesion to stainless steel under specific dynamic flow conditions. It was found that the intrinsic ability of L. monocytogenes to adhere to solid surfaces under flow conditions is dependent on nutrient availability. The addition of L-leucine to the growth medium altered the fatty acid composition of the L. monocytogenes cells and increased adhesion. The growth conditions resulting in the highest adhesion (growth medium with added glucose) had cells with the highest electron donating and lowest electron accepting properties, whereas growth conditions resulting in lowest adhesion (growth medium with added mannose) had cells with the lowest electron donating properties and highest electron accepting properties. The highest and lowest adhesion conditions correlated with differences in expression of cell surface protein of L. monocytogenes and among these the autolysin amidase (Ami). This study implies that food composition influences the adhesion of L. monocytogenes to solid surfaces during dynamic flow conditions.

A comparative study of fine polished stainless steel, TiN and TiN/Ag surfaces: Adhesion and attachment strength of Listeria monocytogenes as well as anti-listerial effect

Magnetron sputtering was used to produce nanocomposite TiN and TiN/Ag coatings on stainless steel surfaces. The surface chemistry (EDX), physicochemical properties (contact angles), topography and roughness parameters (WLP and AFM) of the fine polished stainless steel (FPSS), TiN and TiN/8.6at.% Ag surfaces were examined. Real-time initial adhesion of two Listeria monocytogenes strains (EGDe and 64) to the three surfaces was determined under flow conditions, and their attachment strength after adhesion was measured using atomic force microscopy (AFM). The anti-listerial properties of the surfaces were determined using LIVE/DEAD staining.Our results demonstrate that FPSS, TiN and TiN/8.6at.% Ag possessed different surface properties, which may influence both attachment strength and anti-listerial properties. There were no significant (p>0.05) differences in the initial adhesion of the two L. monocytogenes strains to the three different surfaces. Attachment studies showed that the two L. monocytogenes strains did not attach to FPSS under wetted conditions. However, both strains attached to TiN and TiN/8.6at.% Ag surfaces, although with less strength to TiN/8.6at.% Ag than to TiN surfaces. The TiN/8.6at.% Ag surface showed marked anti-listerial properties as compared with FPSS and TiN. Initial adhesion, attachment strength and anti-listerial properties were found to be strain dependent.

Osteoblastic potency of bone marrow cells cultivated on functionalized biometals with cyclic RGD‐peptide

The fixation of cementless endoprostheses requires excellent fixation at the bone implant interface. Although the surface structures of these implants are designed to promote osteoblastic differentiation, poor bone quality may prevent or delay osseointegration. There is evidence that RGD peptides known as recognition motifs for various integrins, promote cellular adhesion, influence cellular proliferation, and differentiation of local cells. In this study, five different metal surfaces were analyzed: Sandblasted (TiSa) and polished (TiPol) Ti6Al4V, porocoated (CCPor) and polished (CCPol) cobalt chrome and polished stainless steel (SS) were coated by ethanol amine and poly(ethylene glycol) to attach covalently RGD peptides. Human mesenchymal stromal cells of healthy donors were cultivated onto prior functionalized metal surfaces for 14 days without osteogenic stimulation. Cell proliferation and differentiation were quantitatively evaluated for native (I), NaOH pre-activated (II), NaOH pre-activated, and PEG-coated (III) as well as for RGD (IV) coated surfaces. The RGD immobilization efficiency was analyzed by epi-fluorescence spectroscopy, cell morphology was documented by light and scanning electron microscopy. The RGD-binding efficiency was TiSa > TiPol > SS > CCPor > CCPol. RGD coated surfaces showed the highest average cell proliferation on CCPol > SS > CCPor > TiSa ≥ TiPol, whereas cellular differentiation mostly correlated with the observed proliferation results, such as CCPol > TiSa > SS > CCPor > TiPol. Considering statistical analyses (significance level of α = 0.05), the RGD-coating of all biometals in comparison and in respect of their particular controls showed no significant improvement in cellular proliferation and osteoblastic differentiation.

Combined silica sources to prepare preferentially oriented silicalite-1 layers on various supports

Direct in-situ hydrothermal synthesis was optimized via combination of monomeric (TEOS) and colloidal (TOSIL) silica sources to prepare preferentially b-oriented high silica MFI zeolite (silicalite-1) layers on different supports using conventional heating. Crystallographic Preferred Orientation (CPO) indices and our created Preferred Orientation Coverage (POC) values were used to determine preferred orientation and its surface coverage. Particle size distribution of precursor species was measured with Dynamic Light Scattering technique. Crystal intergrowth and zeolite phase purity were checked with Scanning Electron Microscope and X-ray diffraction. Solid and (a+b)-oriented self-supported silicalite-1 layers were synthesized on mercury surface at static and vibration conditions. Additional self-assembled and oriented silicalite-1 layers floating in bulk solution were prepared from solutions with enhanced silica content. Preferentially b-oriented silicalite-1 layers were prepared on silicon wafer and polished non-porous stainless steel. Partial b-orientation was achieved for polished porous stainless steel supports. Remarkably intergrown and b-oriented silicalite-1 layers were synthesized on porous stainless steel covered by TiO2 layer that was impregnated with tetrabutylorthotitanate acting as a coupling agent and/or surface charge modifier.