Reactions of bis(cyclopentadienyl)zirconium dichloride with porous silica surface

2001 ◽  
Vol 183 (3-4) ◽  
pp. 290-300 ◽  
Author(s):  
Minna Kröger-Laukkanen ◽  
Marko Peussa ◽  
Markku Leskelä ◽  
Lauri Niinistö
Keyword(s):  
Silica Surface ◽  
Porous Silica

scholarly journals Some Peculiarities of Silica Modification Under High Reagent Pressure. I. Methodological Aspects

1995 ◽  
Vol 12 (3) ◽  
pp. 231-238 ◽  
Author(s):  
V.V. Sidorchuk ◽  
V.A. Tertykh ◽  
R. Leboda ◽  
Z. Hubicki
Keyword(s):  
Thermal Analysis ◽  
Surface Reaction ◽  
Silica Surface ◽  
Porous Silica ◽  
Physicochemical Characteristics ◽  
Geometrical Parameters ◽  
Duration Of Treatment ◽  
Preparation Conditions ◽  
Modification Process ◽  
Methodological Aspects

The effect of the following factors on the chemical and geometrical modification of aerosilogel (prepared from aerosil) was studied: the physicochemical characteristics of the modifying reagent pressures, the preparation conditions for the silica surface, the reaction temperature, the reagent pressures, the duration of treatment and the method employed for the modification process. The course of the surface reaction was followed by IR spectroscopy, differential thermal analysis and adsorption. During high-pressure modification, the geometrical parameters of the porous silica structure may be changed.

Effect of Sodium Ions on the Dielectric Conductivity of Porous Silica in Humid Environments

1990 ◽  
Vol 195 ◽  
Author(s):  
Wanqing Cao ◽  
Rosario Gerhardt ◽  
John B. Wachtman
Keyword(s):  
Relative Humidity ◽  
Silica Surface ◽  
Porous Silica ◽  
Sodium Content ◽  
Silica Gels ◽  
Interfacial Region ◽  
Relaxation Processes ◽  
Sodium Ions ◽  
Frequency Range ◽  
Dielectric Conductivity

ABSTRACTPartially sintered silica gels were immersed in different NaCI solutions to deliberately introduce a small amount of sodium ions ranging from 387 to 9900 ppm. Dielectric measurements were carried out in the frequency range 12 to 107Hz under various relative humidity conditions. Two relaxation processes were observed in the impedance and modulus planes and were assigned to two separate regions in the hydrated silica surface. The top region is expected to be rich in hydrated sodium since its modulus relaxation time depends strongly on the relative humidity as well as the sodium content. The interfacial region is believed to be composed of structured water since its dielectric conductivity is affected mainly by the amount of water adsorbed on the pore surfaces.

Kinetics of competitive adsorption of polystyrene chains at a porous silica surface

Langmuir ◽  
1994 ◽  
Vol 10 (2) ◽  
pp. 538-541 ◽  
Author(s):  
Masami Kawaguchi ◽  
Yoshimasa Sakata ◽  
Sachio Anada ◽  
Tadaya Kato ◽  
Akira Takahashi
Keyword(s):  
Competitive Adsorption ◽  
Silica Surface ◽  
Porous Silica ◽  
Kinetics Of

scholarly journals Quaternary Ammonium Borohydride Adsorption in Mesoporous Silicate MCM-48

2010 ◽  
Vol 1262 ◽  
Author(s):  
Michael Joseph Wolverton ◽  
Luc L. Daemen ◽  
Monika A. Hartl
Keyword(s):  
Organic Cation ◽  
Silica Surface ◽  
Inelastic Neutron Scattering ◽  
Porous Silica ◽  
Inelastic Neutron ◽  
Hydrogen Release ◽  
Hydrogen Density ◽  
Mesoporous Silicate ◽  
Bet Isotherm ◽  
Lower Temperature

AbstractInorganic borohydrides have a high gravimetric hydrogen density but release H2 only under energetically unfavorable conditions. Surface chemistry may help in lowering thermodynamic barriers, but inclusion of inorganic borohydrides in porous silica materials has proved hitherto difficult or impossible. We show that borohydrides with a large organic cation are readily adsorbed inside mesoporous silicates, particularly after surface treatment. Thermal analysis reveals that the decomposition thermodynamics of tetraalkylammonium borohydrides are substantially affected by inclusion in MCM-48. Inelastic neutron scattering (INS) data show that the compounds adsorb on the silica surface. Evidence of pore loading is supplemented by DSC/TGA, XRD, FTIR, and BET isotherm measurements. Mass spectrometry shows significant hydrogen release at lower temperature from adsorbed borohydrides in comparison with the bulk borohydrides. INS data from partially decomposed samples indicates that the decomposition of the cation and anion is likely simultaneous. These data confirm the formation of Si-H bonds on the silica surface upon decomposition of adsorbed tetramethylammonium borohydride.

C,N-bipyrazole receptor grafted onto a porous silica surface as a novel adsorbent based polymer hybrid

Talanta ◽  
2015 ◽  
Vol 143 ◽  
pp. 1-6 ◽  
Author(s):  
Smaail Radi ◽  
Ahmed Attayibat ◽  
Mohamed El-Massaoudi ◽  
Maryse Bacquet ◽  
Shehdeh Jodeh ◽  
...  
Keyword(s):  
Silica Surface ◽  
Porous Silica ◽  
Polymer Hybrid

Characteristics of the kinetics of exciplex formation between pyrene and N,N-dimethylaniline on a porous silica surface

1997 ◽  
Vol 33 (3) ◽  
pp. 157-160 ◽  
Author(s):  
V. P. Kondilenko ◽  
T. A. Kikteva ◽  
I. G. Tarasov ◽  
A. M. Eremenko
Keyword(s):  
Silica Surface ◽  
Porous Silica ◽  
Exciplex Formation ◽  
Kinetics Of

SiO2 Entrapment of Animal Cells for Hybrid Bioartificial Organs

2000 ◽  
Vol 628 ◽  
Author(s):  
Giovanni Carturan ◽  
Renzo Dal Monte ◽  
Maurizio Muraca
Keyword(s):  
Gas Phase ◽  
Mechanical Stability ◽  
Porous Silica ◽  
Collagen Matrix ◽  
Homogeneous Layer ◽  
Animal Cells ◽  
Bioartificial Organs ◽  
Liver And Pancreas ◽  
Encapsulation Method ◽  
Metabolic Activities

ABSTRACTSi-alkoxides in gas phase are reactive towards the surface of animal cells, depositing a homogeneous layer of porous silica. This encapsulation method preserves cell viability and does not alter the hindrance of the biological load.In the prospective use for the design of a hybrid bioartificial liver, hepatocytes in a collagen matrix can be entrapped by the siliceous deposit which provides definite mechanical stability to the collagen matrix and molecular cutoff vs. high molecular weight proteins, including immunoglobulins. The functionality of the encapsulated cell load is maintained for the expressions of typical liver and pancreas metabolic activities.

Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Continuous Wave ◽  
Silica Surface ◽  
Multi Wall Carbon Nanotubes ◽  
Composite Formation ◽  
Multi Walled Carbon Nanotubes ◽  
Glass Surfaces ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Scanning Electron

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.

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