scholarly journals Kinetics of Enzyme Attack on Substrates Covalently Attached to Solid Surfaces: Influence of Spacer Chain Length, Immobilized Substrate Surface Concentration and Surface Charge

Langmuir ◽  
2008 ◽  
Vol 24 (20) ◽  
pp. 11762-11769 ◽  
Author(s):  
Joseph Deere ◽  
Rui F. De Oliveira ◽  
Bartłomiej Tomaszewski ◽  
Sarah Millar ◽  
Antonia Lalaouni ◽  
...  
Keyword(s):  
Surface Charge ◽  
Chain Length ◽  
Substrate Surface ◽  
Surface Concentration ◽  
Solid Surfaces ◽  
Spacer Chain Length ◽  
Immobilized Substrate ◽  
Kinetics Of

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Adhesion of Fine Particles at Solid/Solution Interfaces

MRS Bulletin ◽  
1990 ◽  
Vol 15 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Nikola Kallay
Keyword(s):  
Fine Particles ◽  
Plane Surface ◽  
Solid Surfaces ◽  
Liquid Media ◽  
Latex Dispersions ◽  
Colloid Particles ◽  
The Subject ◽  
Kinetic Investigations ◽  
The Stability ◽  
Kinetics Of

The adhesion of particles at solid surfaces in liquid media has attracted the attention of scientists because of its various applications as well as the theoretical significance of the processes involved. Early studies were characterized either by poorly defined systems or limited by the properties of a few morphologically well-defined model colloids, such as latex dispersions. Consequently, results were either of semiquantitative nature or were related to some specific cases, which eluded general conclusions. New methods for preparing uniform particles of different compositions, shapes, and sizes make it possible to approach the problem in a more comprehensive manner. For example, to demonstrate difficulties caused by polydispersity, it is sufficient to mention that the electrostatic interaction energy between a plane surface and a particle is approximately proportional to the particle radius, yet the rate of deposition depends exponentially on the height of the energy barrier.In principle, static and dynamic approaches may be employed in the study of particle adhesion. The static method yields the force required to detach an adhered particle, while kinetic investigations of attachment and detachment give the rates of the respective processes. Both methods offer information on the stability of the system in terms of the bond strength of adhered solids. For small colloid particles, which are the subject of thermal random Brownian motion, the dynamic approach is more appropriate. This article emphasizes the kinetics of deposition and detachment of small colloid particles in liquid media.

In situ ATR - FTIR spectroscopy of Hf(IV) tert butoxide adsorption on Si and Ge

2006 ◽  
Vol 917 ◽  
Author(s):  
Shilpa Dubey ◽  
Keijing Li ◽  
Harish Bhandari ◽  
Zheng Hu ◽  
C. Heath Turner ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Density Functional ◽  
Substrate Surface ◽  
Surface Concentration ◽  
Bidentate Ligand ◽  
Initial Reaction ◽  
Process Conditions ◽  
Reaction Cell

AbstractHafnium oxide ultra thin films on Si (100) are being developed to replace thermally grown SiO2 gates in CMOS devices. In this work, a specially designed Attenuated Total Reflectance - Fourier Transform Infra Red Spectroscopy (ATR-FTIR) reaction cell has been developed to observe chemisorption of hafnium (IV) t-butoxide onto a Si and Ge ATR crystal heated up to 250°C and under 1 torr of vacuum to observe the initial reaction pathways and species on the substrate surface in real time and under typical process conditions. Chemisorption spectra were compared to spectra of the liquid precursor and to spectra generated by density functional theory (DFT) calculations of liquid, monodentate and bidentate absorbed precursor. An asymmetric stretching mode located at ~1017 cm-1 present in the chemisorbed spectra but not in the liquid spectra indicates that the adsorbed hafnium containing group is prevalent as a bidentate ligand according to calculations. Surface concentration of the chemisorbed species was dependant on the substrate temperature and precursor partial pressure allowing for determination of heats of adsorption which was 26.5 kJ/mol on Si.

Determination of Spread Activation Energy and Assessment of Wetting Behavior of Solders on Metallic Substrates

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
K. N. Prabhu ◽  
G. Kumar
Keyword(s):  
Surface Roughness ◽  
Operating Temperature ◽  
Substrate Surface ◽  
Substrate Material ◽  
Metallic Substrates ◽  
Wetting Behavior ◽  
Substrate Surface Roughness ◽  
Exponential Power ◽  
Kinetics Of

The effects of substrate material, substrate surface roughness, and operating temperature on the wetting behavior of Sn–37Pb, Sn–3.5Ag, and Sn–9Zn eutectic solders on metallic substrates were investigated. Solder spreading kinetics was successfully represented by the exponential power law (EPL): ϕ=exp(−Kτn). The EPL parameter K has the significance of accelerating the kinetics of relaxation while the parameter n represents the resistance to spreading process (spread resistance parameter). EPL parameters exhibited a decreasing trend with an increase in surface roughness. Estimated activation energies for solder spreading were found to be in between those reported for inert and highly reactive spreading systems.

The Kinetics of Free-Radical Polymerization: Fundamental Aspects

2002 ◽  
Vol 55 (7) ◽  
pp. 399 ◽  
Author(s):  
G. T. Russell
Keyword(s):  
Molecular Weight ◽  
Steady State ◽  
Free Radical ◽  
Radical Polymerization ◽  
Chain Length ◽  
Free Radical Polymerization ◽  
Length Dependence ◽  
Model Independent ◽  
Living Free Radical Polymerization ◽  
Kinetics Of

Some fundamental aspects of the kinetics of free-radical polymerization are reviewed. So-called classical results for rate and molecular-weight distribution are first of all presented. It is shown how this approach can be built upon when chain-length-dependent termination is allowed, which it always should be. Various termination models are considered, and it is illustrated that although the models are different, rather remarkably they give common, model-independent behaviour. Some leading experimental results regarding the chain-length dependence of termination are summarized, before the chain-length dependence of other reactivities, the variation of reactivities with conversion, and non-steady state experiments are briefly discussed. Finally, living free-radical polymerization as effected by a reversible termination agent is considered. An outline of the kinetics of these systems is given, with the oft-neglected importance of conventional termination being stressed.

Thermodynamics of ideal polarizable interfaces

1996 ◽  
Author(s):  
Wolfgang Schmickler
Keyword(s):  
Surface Charge ◽  
Electrolyte Solution ◽  
Solid Surfaces ◽  
Liquid Electrode ◽  
Liquid Electrodes ◽  
Solid Electrodes ◽  
Liquid Surfaces

For liquid electrodes thermodynamics offers a precise way to determine the surface charge and the surface excesses of a species. This is one of the reasons why much of the early work in electrochemistry was performed on liquid electrodes, particularly on mercury - another reason is that it is easier to generate clean liquid surfaces than clean solid surfaces. With some caveats and modifications, thermodynamic relations can also be applied to solid surfaces. We will first consider the interface between a liquid electrode and an electrolyte solution, and turn to solid electrodes later.

Surface Energy and Wettability Study of Flip Chip Packaging Materials

2011 ◽  
Vol 2011 (1) ◽  
pp. 000961-000970
Author(s):  
Jinlin Wang
Keyword(s):  
Surface Energy ◽  
Flip Chip ◽  
Substrate Surface ◽  
Solid Surfaces ◽  
Energy Calculation ◽  
Assembly Process ◽  
Flip Chip Packaging ◽  
Materials Used ◽  
Lead Free Solders ◽  
Ic Package

The surface energy of solid surfaces and surface tension of liquids are important parameters in the IC package assembly process. Wettability analyses have been completed for various materials used in the assembly process of flip chip packages, including underfills, substrates, fluxes, and lead free solders. We will highlight some of these results in this paper. We will focus our discussion on substrate surface energy analysis. A brief discussion of different surface energy methods and the liquid selection criteria will be given. The advantage and limitation of the surface energy calculation methods will be discussed. The data from several case studies will be presented. Our results show that contact angle and surface energy measurements are very useful for quality control and product development where interfacial properties are important.

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