Surface Modification of Montmorillonites by Chlorosilanes

Montmorillonite was modified by chlorosilane derivatives (trimethylchlorosilane and tert-butyldimethylchlorosilane)based on the reaction between OH group and chlorosilane,Fourier-transformed infrared spectra(FTIR)confirmed that chlorosilanes did react with the OH groups of montmorillonite.The effect of reaction time and dispersing agents on the intercalation was studied by wide angle X-ray diffraction(WAXD) method.Further experiments proved that there is no reactive OH group on the surface of layers in the interlayer galleries of montmorillonite.The cation exchange capacity(CEC) of montmorillonites was measured.showing that after modification by chlorosilane derivatives,CEC values drastically decreased.The dispersibility measurements of montmorillonites were conducted.which showed that the dispersibility of modified montmorillonites both in H2O and toluene wer improved due to the decrease of attractions of particles and layers.     

Surface tension of lead–lithium melts

The temperature and concentration dependences of the surface tension of lithium alloys based on lead are experimentally determined for the first time in a field of compositions with up to 20 at % lithium in lead in the temperature range from the liquidus up to 700 K. The isotherm of surface tension of the studied alloys in the range of compositions with ~10 at % Li in lead contains a minimum, as does the adsorption isotherm of lithium in the sub-eutectic area of PbLi compounds.     

Surface oxidation and water desorption of CdS

The surface oxidation and HP desorption of powder CdS were studied by means of X-ray photoetectron spectroscopy (XPS), quadrupole mass spectrometry (QMS) and in-situ FTIR. The results show that with the changes of surface composition and the elongation of store time of CdS there are four types of H2O thermally desorbed at different temperatures. It has also been found that through high-temperature air treatment for a short time the oxidized surface layer of CdS can prevent O2 and H2O in air from further attacking the inner CdS molecules.     

Surface Photovoltage Studies of Moisture Sensitive Characteristic of Copper Tetrasulfonato-Phthalocyanine

The surface photovoltaic characteristic of copper tetrasulfonato- phthalocyanine (CuTsPc) in water vapor was studied by surface photovoltage spectroscopy (SPS). It was found that the adsorption of water vapor caused some marvelous changes of the photovoltaic response, that is, the SPS signal diminished rapidly and even reversed; the bands were widened and displayed a bathochromic shift. The dependence of surface photovoltage on the vapor pressure indicates that the reversed signal reaches to a maximum when the vapor pressure is 4.7×102 Pa. The time response velocity, reversibility, selectivity and reproducibili-ty were examined as well. All results obtained show that CuTsPc is of great significance in the manufacture of moisture sensitive devices. In addition, the mechanism of moisture sensitivity is discussed.     

Modification of Nano-alumina Surface by Michael Addition Reaction

With recent interest in polymer-based nanocomposites, nano-alumina has receivedconsiderable attention because of their high hardness, high strength and good wearresistance. Improvements in mechanical, tribological, conductive and barrier propertiesof some…     

Surface Properties of Cu Doped La-Ni Intermetallic Compounds

A series of Cu-doped La-Ni intermetallic compounds(LaN5-xCux, x = 0-4) was studied. The bulk structure and surface composition of the samples were detected before and after they were used as catalyst for nitrobenzene hydrogennation. The catalytic properties of the intermetallic compounds depend on the surface region composition, especially on the valence of the metal ions.     

Surface Grafting of Phenolic Resole onto LDPE Films

Many studies on surface modification of polymeric membranes have been reported. For example, acrylic acid(shorted as AA) and acrylamide monomers were grafted onto polyethylene, polypropylene and polyethylene terephthalate films in order to minimize the in…     

improvement of the Specificity of Surface Plasmon Resonance with BSA-modified Chip

Recently, surface plasmon resonance (SPR) become more and more popular without the need of the label technology1-3. However, sometimes, a number of experimental artifacts complicate the final biosensor analysis4-7. The utilization of a reference surface c…     

Catalytic Dehydration of α-Phenylethanol on the Surface of Aluminum Oxides

The relationship between the acid–base properties of commercial and test samples of aluminum oxides and their catalytic activity in the dehydration of -phenylethanol was studied. It was found that, in the dehydration of -phenylethanol, the conversion of the alcohol and the yield of styrene on a catalyst depend on the concentrations of both Brønsted and Lewis acid sites. A hypothetical mechanism of the dehydration with the participation of coordinatively unsaturated aluminum atoms and bridging oxygen ions on the alumina surface was proposed.     

Formation of SnO2 Nanoparticles on External Surface of NaY Zeolite

Tin dioxide nanoparticles of 5 nm in size were prepared on NaY zeolite external surface by impregnation of SnCl2 solution and subsequent calcination at 623 K. A SnO2-NaY based chemical sensor for detecting H2 was demonstrated.     

Effect of Amines on the Surface Charge Properties of Iron Oxides

Specific studies detailing the effects of amines, used as pH control agents for corrosion inhibition in power plants, on the surface charge of iron oxides provide data to assess the mechanism of how these amines impact deposition rate. The current study was undertaken in order to determine accurately the dissociation constants of the relevant amines at Pressurized Water Reactor (PWR) operating conditions and to investigate the effect of sorption of two of these amines (morpholine and dimethylamine) by magnetite. The acid-dissociation equilibria of morpholine (MOR), dimethylamine (DMA) and ethanolamine (ETA) were measured potentiometrically with a hydrogen-electrode concentration cell (HECC) from 0 to 290 °C in sodium trifluoromethanesulfonate (NaTr) solutions at ionic strengths up to 1 mol⋅kg⁻¹. Magnetite surface titrations were performed at an ionic strength of 0.03 mol⋅kg⁻¹ (NaTr medium) in the presence or absence of morpholine and dimethylamine buffers over a wide range of pH and total amine concentrations at 150–250 °C. D.A. Palmer is retired.     

Surface properties of sol–gel-based fluorine-containing ceramic coatings

In this work, sol–gel-based non-stick ceramic coating formulations were prepared and coated onto aluminum panels in order to investigate their surface properties. The effect of the addition of optimal amount of fluorine-containing silane compound (FAS) on the surface and adhesion properties were also investigated. The morphology, structure, and elemental chemical composition of the coatings were characterized by scanning electron microscopy, atomic force microscopy (AFM), energy dispersion spectrum (SEM/EDAX), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), respectively. Moreover, several properties of the coatings such as cross-cut adhesion, hardness, gloss, and contact angle (CA) were determined. When fluorine was introduced, the pencil hardness was increased to 6H. Fluorinated non-stick ceramic coatings were found to have good adhesion on the aluminum substrates.

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Radiation-Thermal Processes at the Surface of Pyrogenic γ-Alumina

The effects of ⁶⁰Co -radiation, 75-keV electrons, and thermal history (295–973 K) on the surface properties of pyrogenic -Al₂O₃ were studied by thermal desorption mass spectrometry. It was found that the state of a hydroxyl cover and the concentrations of surface acid–base sites and chlorine impurity atoms can be regulated by changing the conditions of oxide irradiation.     

Surface Modification of Silica Gels as Carrier for AminoacylaseImmobilization

IrnmobilisedaIninoacylaseisanotablecatalystforthekineticresolutionofN-acetyl-D,L-aIninoacidsandquitealotofresearchworkhasbeeninvolvedonaminoacylase~bilisationswithitscarriers.lTheauthorshaverePortedthattheaIninosilicagelspreparedbyanlinProvedmethodwereeffechveforchymotryPsininunobilisahon,'l'butitwasnotproperforaIninoacylasetriobilisahon.InordertodevelopasahsfactorysurfacesmictUreofsilicagelsforaIninoacylasetriobilisation,tWokindsofreactivegrouPs,theN,N-diethylaIninogrouPandthehydroxygr…     

Preparation and Surface Modification of Novel Vesicular Nano-Particle “Cerasome” with Liposomal Bilayer and Silicate Surface

A novel class of nano-hybrid materials, Cerasome, bearing a liposomal bilayer structure and a ceramic surface, has been developed by a sol-gel reaction of a double-chain proamphiphile having an trialkoxysilane in the head moiety and followed self-assembling. In the present work, we developed new methods for preparation of the Cerasomes forming under various pH conditions and their surface modification by employing appropriate alkoxysilane compounds. When the proamphiphilic alkoxysilane was hydrolyzed in an acidic ethanol and then injected into an aqueous media at various pH, the morphologically stable Cerasomes were obtained in a wide pH range. On the other hand, an acid treatment of the proamphiphile in ethanol in the presence of tetraethoxysilane gave the Cerasome with highly developed siloxane networks on its vesicular surface. Surface modification of the Cerasome with amino groups was readily achieved in the similar manner by replacing tetraethoxysilane to 3-aminopropyltriethoxysilane. The Cerasomes thus prepared were characterized by means of dynamic light scattering and zeta potential measurements.     

Quantitative Structure—Property Relationship on Prediction of Surface Tension of Nonionic Surfactants

When a surfactant is solved into a solvent, it will adsorb onto the surface of the solution and reduce the surface free energy to a marked degree. The surface free energy, which is the minimum amount of work required to create that surface, is usually measured by surface tension. The minimum of surface tension 0g is the most useful key for characterizing the activity of surfactant. It is well known that 0g is determined by the molecular structure of surfactant, i.e., the contributions from …     

Probing the Brønsted Acidity of the External Surface of Faujasite-Type Zeolites

We outline two methodologies to selectively characterize the Brønsted acidity of the external surface of FAU-type zeolites by IR and NMR spectroscopy of adsorbed basic probe molecules. The challenge and goal are to develop reliable and quantitative IR and NMR methodologies to investigate the accessibility of acidic sites in the large pore FAU-type zeolite Y and its mesoporous derivatives often referred to as ultra-stable Y (USY). The accessibility of their Brønsted acid sites to probe molecules (n-alkylamines, n-alkylpyridines, n-alkylphosphine- and phenylphosphine-oxides) of different molecular sizes is quantitatively monitored either by IR or ³¹P NMR spectroscopy. It is now possible, for the first time to quantitatively discriminate between the Brønsted acidity located in the microporosity and on the external surface of large pore zeolites. For instance, the number of external acid sites on a Y (LZY-64) zeolite represents 2 % of its total acid sites while that of a USY (CBV760) represents 4 % while the latter has a much lower framework Si/Al ratio.     

Surface tension evolution during early stages of drying of sol–gel coatings

Striation defects in spin-coated thin films have been blamed on unfavorable capillary forces that occur due to solvent evaporation commonly experienced during coating deposition. Solvent evaporation during spinning causes predictable composition changes at the surface and these can either stabilize or de-stabilize the surface with respect to convective motions within the coating solution. The present work examines the surface tension changes while adding the most volatile component rather than removing it. This is then a “reverse drying” process, but it provides us with the slope of the surface tension change during normal coating drying. We have examined coating solutions for a case where a specific solvent addition has previously been shown to prevent the formation of striation defects. By measuring both the starting solution (one that produces bad striation defects) and the co-solvent-modified solution (that produces much flatter coatings), we are able to demonstrate the correlation between surface tension changes during spinning and the striation defect formation (or prevention). For the present case, an aluminum-titanate sol–gel recipe, the solvent that eliminated the striation defects is also responsible for a continuous, gradual, reduction in surface tension during the spin-on process, consistent with a model proposed earlier (D. P. Birnie, J Mater Res 16:1145–1154, 2001).     

Miceliization and Surface Adsorption of Tetraethylammonium Perfluorooctanesulfonate in Mixed Solvents

The surface tension and cenductivity of tetracthylarnmomum perfluorooctanesulfonate (TEPFOS) solu-tions in mixed solvents were determined The criticsl micelle concentrations (cmc) and surface adsorption of TEPFOS in various solvents (Dimetbylsulfoxlde and DMSO, formamide and FA, and DMSO-H2O and FA H2O mixtures) were calculated from the above experimental date. The results show that the surface activity of TEPFOS is much higher than that of typical hydrocarbon surfactant, sodium dodecylsulfate (SDS); the melecalar interaction (in terms of colubility araneter or surface tension) of solvent is the decisive factor in sffecting the cmc of TEPFOS , in the apretic solvent DMSO, the value of entropy change during micelliza-tion of TEPFOS may beecme subsantially negative; the surfaof adsorption amount of TEPFOS is the largest in H2O, smaller in FA , and the smallest in DMSO.     

Surface Modification of Nano-SiO_2 by Grafting PMMA/PBA

IntroductionThankstotheirsizesatnano level ,thenano particleshavesomenewandpreternaturalpropertiesdifferentfromnormalmaterials ,andtheycanbeappliedinmanyfieldssuchascatalysts,lightfiltration ,lightabsorbing ,medicine ,magneticmediumandnewmaterialsaswell.1,2Itisalsorecognizedasoneofthemostprosperousmateri alsinthe 2 1century .Nowadays ,scientistsandre searcherspaymoreattentiontopolymer nano inorganiccompounds,becausepolymeriseasytoprocess ,anditcanavoidtheoxidationandcoagulationofthenano parti …