Surface Free Energy Modification of Crude Rubber Using Oxygen Plasma and Uv Laser Treatment

2013 ◽  
Vol 21 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Gorazd Golob ◽  
Marta Klanjšek Gunde ◽  
Marie Kaplanová ◽  
Mladen Lovreček ◽  
Miran Mozetič
Keyword(s):  
Free Energy ◽  
Laser Treatment ◽  
Surface Free Energy ◽  
Oxygen Plasma ◽  
Uv Laser

Influence of Oxygen Plasma Modification on Surface Free Energy of PMMA Films and Cell Attachment

2008 ◽  
Vol 269 (1) ◽  
pp. 128-137 ◽  
Author(s):  
Canturk Ozcan ◽  
Pınar Zorlutuna ◽  
Vasıf Hasirci ◽  
Nesrin Hasirci
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Oxygen Plasma ◽  
Cell Attachment ◽  
Plasma Modification

Surface modification of polyimide fibers by oxygen plasma treatment and interfacial adhesion behavior of a polyimide fiber/epoxy composite

2017 ◽  
Vol 24 (4) ◽  
pp. 477-484 ◽  
Author(s):  
Xuyang Sun ◽  
Junfeng Bu ◽  
Weiwei Liu ◽  
Hongqing Niu ◽  
Shengli Qi ◽  
...  
Keyword(s):  
Free Energy ◽  
Plasma Treatment ◽  
Surface Free Energy ◽  
Photoelectron Spectroscopy ◽  
Interfacial Adhesion ◽  
Oxygen Plasma ◽  
Dynamic Contact Angle ◽  
Epoxy Composites ◽  
Oxygen Plasma Treatment ◽  
Adhesion Properties

AbstractOxygen plasma was used to enhance the surface behavior of polyimide (PI) fibers and PI fiber-reinforced epoxy composites were prepared in our present work. The effects of plasma treating times on the surface properties of PI fiber and the interfacial adhesion of PI fiber/epoxy composites were investigated. Surface chemical composition, surface morphologies and surface free energy of the fibers were characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and dynamic contact angle analysis, respectively. The results suggest that some oxygen functional groups were introduced onto PI fiber surfaces, and the surface roughness of fibers was enhanced. Resultantly, the surface free energy of fibers and the interfacial adhesion of composites were improved by the oxygen plasma treatment. The interlaminar shear strength of the composites increased to 70 MPa when the fibers were treated for 10 min, which proved good interfacial adhesion properties.

Surface modification of high-performance polyimide fibers by oxygen plasma treatment

2016 ◽  
Vol 29 (9) ◽  
pp. 1083-1089 ◽  
Author(s):  
You Wen ◽  
Xiangsheng Meng ◽  
Jingfeng Liu ◽  
Jingling Yan ◽  
Zhen Wang
Keyword(s):  
Tensile Strength ◽  
Free Energy ◽  
Surface Modification ◽  
Surface Free Energy ◽  
Oxygen Concentration ◽  
Epoxy Resins ◽  
Oxygen Plasma ◽  
Plasma Power ◽  
Single Filament ◽  
Untreated Fiber

In order to improve the interfacial compatibility between the fibers and epoxy resins, polyimide (PI) fibers were modified using oxygen plasma with various treatment powers. The properties of PI fibers before and after surface modification were comparatively characterized according to their chemical composition, surface morphology, surface free energy, single filament tensile strength, and interfacial shear strength (IFSS). Most of the fiber properties, including the ratio of oxygen to nitrogen, oxygen concentration, surface free energy, and IFSS firstly increased with the plasma power, and then decreased when the plasma power was higher than 120 W. With a plasma power of 120 W, the oxygen concentration and the ratio of oxygen to carbon atoms (O/C) was 26% (22% for untreated fiber) and 0.38 (0.28 for untreated fiber), respectively. Meanwhile, the values of surface free energy and IFSS were 89% and 30% higher than those for untreated fiber, respectively. Furthermore, the values of single filament tensile strength for modified fibers were only 2.3% lower than those for pristine one. These results indicated that the compatibility between PI fibers and epoxy resins was greatly improved without compromising mechanical properties.

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.

Bifunctional Composites for Biofilms Modulation on Cervical Restorations

2021 ◽  
pp. 002203452110181
Author(s):  
A.A. Balhaddad ◽  
I.M. Garcia ◽  
L. Mokeem ◽  
M.S. Ibrahim ◽  
F.M. Collares ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angles ◽  
Bacterial Biofilm ◽  
Dental Composite ◽  
Log P ◽  
Rrna Gene ◽  
Cervical Lesions ◽  
Biofilm Growth ◽  
Biofilm Development

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.

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