Polar and dispersion force contributions to the total surface free energy of wood

1978 ◽  
Vol 12 (1) ◽  
pp. 63-74 ◽  
Author(s):  
T. Nguyen ◽  
W. E. Johns
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Dispersion Force ◽  
Total Surface Free Energy

Interactions of components and elements of the surface free energy at interfaces

1991 ◽  
Vol 56 (2) ◽  
pp. 277-295 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Polar Phase ◽  
Free Energies ◽  
Dispersion Component ◽  
Liquid Systems ◽  
Interfacial Free Energies ◽  
Total Surface Free Energy ◽  
Solid Liquid ◽  
New Hypothesis

A new hypothesis is suggested for the evaluation of the components (γd and γab) and the elements (γa and γb) of the surface free energy. The respective equations are introduced for the interactions at interfaces between a non-polar acid and non-polar base, a polar phase and non-polar acid or base, and two polar phases. The dispersion component, γd, equals the total surface free energy of non-polar phases. However, they can interact at the interface as an acid or a base through their single permanent elements γa or γb, respectively. Otherwise, induced elements γia and γib can also be effective. The surface free energy of polar phases is additively composed of the dispersion, γd, and acid-base components, γab = 2(γaγb)1/2. The proposed equation are verified using the known values of the surface and interfacial free energies for the liquid-liquid systems and they are applied to the solid-liquid interfaces. The values of the elements are determined for water, γwa = 67.7 and γwb = 10.6 mJ/m2, and for other liquids, such as glycerol, formamide, mercury, benzene, diethyl ether and trichloromethane.

Investigation of some phenomena occurring during continuous ink-jet printing of ceramics

2001 ◽  
Vol 16 (2) ◽  
pp. 373-384 ◽  
Author(s):  
B. Y. Tay ◽  
M. J. Edirisinghe
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Surface Free Energy ◽  
Modulation Frequency ◽  
Free Energies ◽  
Ink Jet Printing ◽  
Ink Jet ◽  
Jet Printing ◽  
Vertical Walls ◽  
Total Surface Free Energy

A ceramic ink was prepared, characterised, and subjected to continuous ink-jet printing. The optimum modulation frequency for printing was estimated. The surface free energies of several substrates were determined and different patterns of the ink droplets were printed on these. Phenomena occurring during the process were investigated. The drop-by-drop resolution and ink spreading were found to be dependent on the dispersive/total surface free energy ratio of the substrates. Ink drying was accompanied by powder migration in the droplets deposited on substrates with a surface free energy lower than the surface tension of the ink. Printing of multiple layers was accompanied by the appearance of ridges, splattering, and non-vertical walls. The causes of these phenomena are discussed in this paper.

scholarly journals WETTING PROPERTIES OF CHITOSAN-MODIFIED AND PLASMA-TREATED PEEK SURFACES

2018 ◽  
Vol XXIII ◽  
pp. 159-169 ◽  
Author(s):  
Kacper Przykaza ◽  
Małgorzata Jurak ◽  
Agnieszka E. Wiącek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angle Hysteresis ◽  
Chitosan Film ◽  
Film Surface ◽  
Contact Angles ◽  
Biologically Active ◽  
Air Plasma ◽  
Wetting Properties ◽  
Total Surface Free Energy

In this paper, the wettability of chitosan/phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine – DPPC), chitosan/lipid (cholesterol – Chol) and chitosan/protein (cyclosporine A – CsA) films on air plasma activated polyetheretherketone (PEEK) plates was studied. The layers were prepared using the solution spreading technique and their surface wetting properties were determined based on the measurements of the advancing and receding contact angles of water, formamide and diiodomethane. Moreover, based on the contact angle hysteresis model of Chibowski, values of total surface free energy were estimated. Significant changes in PEEK polarity were observed after plasma activation and modifications with Ch/DPPC, Ch/Chol and Ch/CsA layers. These molecules modulate the chitosan film surface by changing the type and magnitude of interactions, which is revealed in the values of surface free energy. These results may be important for the development and implementation of highly biocompatible bone substitution polymers coated with chitosan film with anti-fungal and anti-bactericidal properties. Those systems based on chitosan may also carry and release biologically active substances which could be relevant in the new generation of drug delivery systems.

Experimental investigation of the Y2BaCuO5 surface free energy during peritectic solidification of YBCO

1998 ◽  
Vol 13 (8) ◽  
pp. 2035-2038 ◽  
Author(s):  
Wai Lo ◽  
D. A. Cardwell ◽  
J. C. L. Chow ◽  
H-T. Leung
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Energy Analysis ◽  
Particle Segregation ◽  
Peritectic Solidification ◽  
Triple Points ◽  
Total Surface Free Energy ◽  
Free Energy Analysis ◽  
Particle Pushing ◽  
Pure Ybco

The characteristic inhomogeneous distribution of nonsuperconducting Y2BaCuO5 (211) inclusions in melt-processed YBa2Cu3O7−δ (123) grains has generally been attributed to 211 particle pushing by 123 growth fronts during peritectic solidification on the basis of reduced total surface free energy. Analysis of the morphology of the interfaces at the 211–211–123 and 211–211-liquid triple points in seeded melt-processed samples invalidates this assumption for the pure YBCO system and has implications of the mechanism of 211 particle segregation.

Smectic A-Smectic B interface : faceting and surface free energy measurement

1989 ◽  
Vol 50 (24) ◽  
pp. 3527-3534 ◽  
Author(s):  
P. Oswald ◽  
F. Melo ◽  
C. Germain
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Energy Measurement ◽  
Smectic A

Examination of the lubricant storing and releasing ability of thermally sprayed surfaces

2011 ◽  
Vol 2 (2) ◽  
pp. 101-105
Author(s):  
L. Fazekas ◽  
Z. S. Tiba ◽  
G. Kalácska
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Essential Role ◽  
Index Number ◽  
Adhesion Ability ◽  
Thermally Sprayed ◽  
Proper Operation

Abstract The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.

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.

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