On the analysis of surface free energy of DLC coatings deposited in low pressure RF discharge

2004 ◽  
Vol 54 (S3) ◽  
pp. C877-C882 ◽  
Author(s):  
Z. Navrátil ◽  
V. Buršíková ◽  
P. St’ahel ◽  
M. Šíra ◽  
P. Zvěřina
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Low Pressure ◽  
Rf Discharge ◽  
Dlc Coatings

scholarly journals Influence of Low-Pressure RF Plasma Treatment on Aramid Yarns Properties

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3476
Author(s):  
Alicja Nejman ◽  
Irena Kamińska ◽  
Izabela Jasińska ◽  
Grzegorz Celichowski ◽  
Małgorzata Cieślak
Keyword(s):  
Weight Loss ◽  
Free Energy ◽  
Radio Frequency ◽  
Plasma Treatment ◽  
Surface Free Energy ◽  
Low Pressure ◽  
Rf Plasma ◽  
Polar Component ◽  
Specific Strength ◽  
Dispersion Component

The aim of the study was to modify the surface free energy (SFE) of meta- (mAr) and para-aramid (pAr) yarns by their activation in low-pressure air radio frequency (RF) (40 kHz) plasma and assessment of its impact on the properties of the yarns. After 10 and 90 min of activation, the SFE value increased, respectively, by 14% and 37% for mAr, and by 10% and 37% for pAr. The value of the polar component increased, respectively by 22% and 57% for mAr and 20% and 62% for pAr. The value of the dispersion component for mAr and pAr increased respectively by 9% and 25%. The weight loss decreased from 49% to 46% for mAr and 62% to 50% for pAr after 90 min of activation. After 90 min, the specific strength for mAr did not change and for pAr it decreased by 40%. For both yarns, the 10 min activation in plasma is sufficient to prepare their surface for planned nanomodification.

scholarly journals Surface modification of polycarbonate (bisphenol A) by low pressure rf plasma

1970 ◽  
Vol 1 (2) ◽  
pp. 115-118 ◽  
Author(s):  
Deepak P Subedi ◽  
Lenka Zajickova ◽  
Vilma Bursikova ◽  
Jan Janca
Keyword(s):  
Free Energy ◽  
Surface Modification ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Photoelectron Spectroscopy ◽  
Peel Test ◽  
Low Pressure ◽  
Rf Plasma ◽  
Modified Surface ◽  
The Stability

Effects of low pressure radio frequency (rf) plasma treatment on the surface properties of polycarbonate are presented in this paper. Results obtained from the surface energy measurement after different conditions of treatment are compared. After treatment the surface free energy increased from the original value of 35 mJ/m2 to 63-74 mJ/m2. X-ray photoelectron spectroscopy measurements showed an increase in oxygen to carbon ratio after the treatment indicating an increase of oxygen-containing functional groups on the polycarbonate surface. A study of the stability of the modified surface property has been made on the basis of surface free energy. To study the improvement of adhesion between the polycarbonate and thin coatings, organosilicon thin films were deposited on the untreated and plasma treated polycarbonate. The adhesion of film to substrate was quantitatively analysed by ‘cross-hatch peel test’. Key words: Polycarbonate, surface modification, rf plasma, ageing, surface energy Himalayan Journal of Sciences 1(2): 115-118, 2003

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.

scholarly journals Effect of calcination temperature on neptunium dioxide microstructure and dissolution

2020 ◽  
Vol 7 (12) ◽  
pp. 3869-3876
Author(s):  
Kathryn M. Peruski ◽  
Brian A. Powell
Keyword(s):  
Grain Size ◽  
Free Energy ◽  
Surface Area ◽  
Calcination Temperature ◽  
Surface Free Energy ◽  
Neptunium Dioxide

Solubility of neptunium dioxide decreases as microstructure grain size increases, likely due to decreasing surface free energy and surface area.

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