Formation of Surface Structure in Vulcanizates and Surface Structure Changes in Air

1995 ◽  
Vol 68 (1) ◽  
pp. 97-109 ◽  
Author(s):  
Kunio Mori ◽  
Kentaro Kanae ◽  
Hidetoshi Hirahara ◽  
Yoshiyuki Oishi
Keyword(s):  
Free Energy ◽  
Surface Structure ◽  
Surface Free Energy ◽  
High Surface ◽  
Surface Region ◽  
Interfacial Free Energy ◽  
Chemical Compositions ◽  
Free Energies ◽  
Dry Air ◽  
Structure Changes

Abstract The formation theory of surface structure during vulcanization was developed on the basis of an interfacial concept. The theory showed the chemical compositions of polar and nonpolar components on the vulcanizate surface to be determined as an excess interfacial free energy between rubber compounds and molds decreases. The surface free energies of molds reflected clearly the corresponding surface free energy of vulcanizates prepared from copolymers and polar polymers. Nonpolar polymers were not influenced by the surface free energies of molds. The surface free energies of vulcanizates decreased slightly with the concentration of network chains owing to the entropy of rubber segments. The surface free energies of molds affected the chemical compositions at the topmost surface region to the upper surface region on vulcanizates. NBR vulcanizates with high surface free energy increased the contact angle of water after standing in dry air. In the dry air environment, topmost surface layer nitrile groups were buried in the bulk of NBR vulcanizates and butadiene units subsequently overturn to the topmost, layer. In this case, the vulcanizate surface chemical composition was influenced only at the topmost surface region. ESCA spectra N1s peak intensities on NBR vulcanizates was consistent with these observation.

Molecular orientation of liquid aliphatic hydrocarbons on the surface and at the interface with water

1989 ◽  
Vol 54 (12) ◽  
pp. 3171-3186 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Molecular Orientation ◽  
Phase Changes ◽  
Aliphatic Hydrocarbons ◽  
Water Molecules ◽  
Free Energies ◽  
Dispersion Component ◽  
System Water ◽  
Orientation Of Molecules

The validity of the Fowkes theory for the interaction of dispersion forces at interfaces was inspected for the system water-aliphatic hydrocarbons with 5 to 16 C atoms. The obtained results lead to the conclusion that the hydrocarbon molecules cannot lie in a parallel position or be randomly arranged on the surface but that orientation of molecules increases there the ration of CH3 to CH2 groups with respect to that in the bulk. This ratio is changed at the interface with water so that the surface free energy of the hydrocarbon, γH, rises to a higher value, γ’H, which is effective in the interaction with water molecules. Not only the orientation of molecules depends on the adjoining phase and on the temperature but also the density of hydrocarbons on the surface of the liquid phase changes. It is lower than in the bulk and at the interface with water. Moreover, the volume occupied by the CH3 group increases on the surface more than that of the CH2 group. The dispersion component of the surface free energy of water, γdW = 19.09 mJ/m2, the non-dispersion component, γnW = 53.66 mJ/m2, and the surface free energies of the CH2 and CH3 groups, γ(CH2) = 32.94 mJ/m2 and γ(CH3) = 15.87 mJ/m2, were determined at 20 °C. The dependence of these values on the temperature in the range 15-40 °C was also evaluated.

The Stabilization of Supported Au Nanoparticles in a Highly Sintering Environment using High Surface Free Energy Pt and Ru Cores

2021 ◽  
Author(s):  
Kerry O-Connell ◽  
John R Monnier ◽  
John Regalbuto
Keyword(s):  
Gold Nanoparticles ◽  
Free Energy ◽  
Surface Free Energy ◽  
Au Nanoparticles ◽  
High Surface ◽  
Chemical Environment ◽  
Core Shell

In an effort to stabilize gold nanoparticles which sinter rapidly in a highly corrosive chemical environment, the hydrochlorination of acetylene, bimetallic Ru@Au and Pt@Au core-shell catalysts were prepared by anchoring...

ADSORPTION OF BENZENE AND ETHANOL UP TO HIGH RELATIVE PRESSURES ON FINELY DIVIDED SODIUM CHLORIDE: PART I. PARTICLE SIZE EFFECTS AND THE ADSORPTION OF BENZENE: PART II. THE LOWERING OF SURFACE FREE ENERGY BY ETHANOL

1961 ◽  
Vol 39 (6) ◽  
pp. 1360-1371 ◽  
Author(s):  
R. R. Weiler ◽  
J. Beeckmans ◽  
R. McIntosh
Keyword(s):  
Free Energy ◽  
Sodium Chloride ◽  
Surface Free Energy ◽  
Convex Surface ◽  
Plane Surface ◽  
Saturated Vapor ◽  
Thick Layer ◽  
Interfacial Free Energy ◽  
Relative Pressure ◽  
Adsorption Data

Adsorption of benzene has been studied using four samples of fine sodium chloride. The range of relative pressures employed extended to 0.99. The data were employed to show that a correction to the relative pressure should be applied because of the curvature of the surface. The correction was made in the form of a reduction of the apparent relative pressure by application of the Kelvin equation, since the relative pressure over a convex surface would be less than over a plane surface. The adsorption data at high relative pressures for several samples of salt could then be represented by a common curve. It was further concluded that the thick-layer theory of adsorption due to Frenkel, Halsey, and Hill was applicable to adsorption on salt. Adsorption data for ethanol were then obtained and the reduction of surface free energy of the salt by the saturated vapor was evaluated. This figure was then combined with van Zeggeren's and Benson's value of the solid–liquid interfacial free energy for salt and ethanol to provide a provisional value of the surface free energy of sodium chloride of 227 ergs cm−2.

Quantitative Evaluation of the Interfacial Free Energies at A Solid-Liquid Lamellar Eutectic Interface

1981 ◽  
Vol 12 ◽  
Author(s):  
W. F. Kaukler ◽  
J. W. Rutter
Keyword(s):  
Free Energy ◽  
Solid Phase ◽  
Interfacial Free Energy ◽  
Eutectic System ◽  
Liquid Interfaces ◽  
Free Energies ◽  
Two Phases ◽  
Interfacial Free Energies ◽  
The Individual ◽  
Solid Liquid

The solid-liquid interfacial free energies of each of the individual phases comprising the eutectic system, Carbon Tetrabromide-Hexachloroethane, were measured as a function of composition using a “grain boundary groove” technique. Thermodynamic data were combined with groove shape measurements made from high resolution optical photomicrographs of the solid-liquid interfaces to give the interfacial free energy data. An interfacial free energy balance at the eutectic trijunction was performed to obtain all the forces acting on that point. The three interphase interfacial free energies at the eutectic trijunctions as well as a solid-solid phase boundary torque were evaluated.It was found that the solid-liquid interfacial free energies of the two phases of the eutectic could be evaluated from photomicrographs of growing or stationary eutectic interfaces. In addition, it was found that for a substantial range of freezing conditions the eutectic interface shape can be predicted from a knowledge of the interfacial free energies alone.

Solid surface free energy analysis using inkjet droplets

2011 ◽  
Vol 1360 ◽  
Author(s):  
Kazuhiro Fukada ◽  
Hayato Sakai ◽  
Taku Hasobe ◽  
Takashi Masuda ◽  
Tatsuya Shimoda
Keyword(s):  
Electron Microscopy ◽  
Free Energy ◽  
Surface Free Energy ◽  
Energy Analysis ◽  
Free Energies ◽  
Organic Solution ◽  
Transmission Electron ◽  
Free Energy Analysis ◽  
The Relationship ◽  
Tem Grid

ABSTRACTWe measured the surface free energy of a substrate by transmission electron microscopy (TEM) using sub-millimetre-sized inkjet droplets. By employing two types of TEM grids with different surface free energies, we investigated the relationship between the surface energy and the patterns of an organic solution dried on the grids. We confirmed that the generation of the porphyrin hexamer [(H2PAC15)6TPh] patterns was affected by the surface free energy of the TEM grid.

Biopolymer Blends as Potential Biomaterials and Cosmetic Materials

2013 ◽  
Vol 583 ◽  
pp. 95-100 ◽  
Author(s):  
Alina Sionkowska ◽  
Katarzyna Lewandowska ◽  
A. Planecka ◽  
P. Szarszewska ◽  
K. Krasinska ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Silk Fibroin ◽  
High Surface ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Polymeric Blends ◽  
Contact Angle Measurements

Blends of two polymer, namely chitosan with silk fibroin or partially hydrolysed polyacrylamide (HPAM) were prepared. The surface properties of chitosan/silk fibroin and chitosan/HPAM blended films were investigated using the technique of Atomic Force Microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films and chitosan/silk fibroin films were made and surface free energy was calculated. It was found that chitosan/silk fibroin blend surface is enriched in high surface energy component i.e. silk fibroin. The surface roughness of chitosan, silk fibroin, HPAM, chitosan/silk fibroin and chitosan/HPAM blended films differs with the composition of the blend. Film-forming polymeric blends can be potentially used as biomaterials and cosmetic materials.

Influence on Friction Force of Adhesion Force between Vulcanizates and Sliders

1994 ◽  
Vol 67 (5) ◽  
pp. 797-805 ◽  
Author(s):  
Kunio Mori ◽  
Satoshi Kaneda ◽  
Kentaro Kanae ◽  
Hidetoshi Hirahara ◽  
Yoshiyuki Oishi ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
Adhesion Force ◽  
High Surface ◽  
Low Surface Energy ◽  
Polar Groups ◽  
Slider Surface ◽  
The Coefficient Of Friction

Abstract The effects of vulcanizate and slider surface free energy—as well as the adhesion force (P) between them—on friction the force (F) and the coefficient of friction (μ) has been investigated. SBR and NBR vulcanizates were prepared using three molds differing in surface free energy. The mold with a high surface free energy gave a vulcanizate surface possessing polar groups. The mold with low surface energy gave a vulcanizate surface with many nonpolar groups. The coefficient of friction increased with the surface free energy of SBR and NBR vulcanizates. With SBR vulcanizate (surface free energy, 31.3 mJ·m−2) and teflon slider (surface free energy, 28.1 mJ·m−2) combination having the least surface free energy, the coefficient of friction was constant at greater than a 0.2N load. With vulcanizates and an aluminum slider with high surface free energy, friction force could be detected even at zero load because of the adhesion force at the interface. Friction force increased linearly with adhesion force between vulcanizates and sliders when the physical properties of the vulcanizates and net work chain density were constant. The present results clearly demonstrate the contribution of adhesion force to the friction of vulcanizates.

Determining Interfacial Free Energies from Creep Experiments on Silver-Iron Multilayers

1994 ◽  
Vol 356 ◽  
Author(s):  
D. Josell ◽  
Z.L. Wang
Keyword(s):  
Thin Films ◽  
Free Energy ◽  
Boundary Diffusion ◽  
Interfacial Free Energy ◽  
Multilayer Thin Films ◽  
Free Energies ◽  
Diffusion Controlled ◽  
Interfacial Free Energies ◽  
Over Time ◽  
Microstructural Data

AbstractExperiments were conducted on multilayer thin films to determine the free energies associated with silver/iron interfaces. Creep studies determined the loads for which the multilayers neither shrank nor stretched over time. Microstructural data was used with the zero creep loads in a model for grain boundary diffusion controlled creep in multilayers to determine the interfacial free energy.

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