Plasma polymerization of CF4 + H2 mixtures on the surface of polyethylene and polyvinylidene flouride substrates

Improvement of Water Barrier Properties of Poly(ethylene-co-vinyl alcohol) Films by Hydrophobic Plasma Surface Treatments

“…However, further increase of H 2 or C 2 H 2 content provokes a drastic decrease of the hydrophobicity that may be caused by the decreasing fluorine reactive species quantity. The similar results were found in the case of other fluorocarbon films obtained for C n F (2 n +2) /H 2 mixtures. − The results of optical emission spectroscopy showed that the fluorine atom concentration passed through a minimum between 10 and 18% of hydrogen owing to the formation of the unreactive stable HF compound and then increased again. , The optimized plasma conditions for CF 4 /H 2 and CF 4 /C 2 H 2 gas mixtures are presented in Table .…”

“…However, for EVOHDT29 film treated by CF 4 /H 2 plasma, the peak attributed to the presence of CF 3 groups on the film surface (at 688.7 eV) was found to be twice higher than that of CF groups (at 686.1 eV) (Figure b). This confirms that the presence of hydrogen in CF 4 plasma gas leads to the creation of very stable HF molecules. , Besides, it is known that CF 3 and CF 2 groups make the main contribution to the hydrophobic nature of the material …”

“…D’Agostino et al studied the effect of the hydrogen addition, a scavenger of fluorine atoms, to C n F (2 n +2) discharges. ,, The fluorine atom concentration was found to decrease and the CF • and CF 2 • radical concentrations were found to increase with increasing hydrogen percentage. The hydrogen in the plasma phase reacts with the atomic fluorine that leads to the creation of very stable HF molecules which are inactive in the plasma atmosphere. − On the other hand, it is known that the presence of C 2 H 2 in plasma improves the barrier properties by the formation of a polymerized layer on the treated surface. This hydrophobic layer has a compact tridimensional network and may serve as a barrier for permeant diffusion. , Therefore, mixtures of CF 4 with H 2 and C 2 H 2 gases were used in order to enhance the hydrophobicity of EVOH films.…”

“…This confirms that the presence of hydrogen in CF 4 plasma gas leads to the creation of very stable HF molecules. 26,27 Besides, it is known that CF 3 and CF 2 groups make the main contribution to the hydrophobic nature of the material. 11 To better understand the fluorined plasma treatment and to know about the fluorine plasma effect in depth, XPS sputtering has been carried out.…”

Silicon contamination of substrates in fluorocarbon plasmas produced in glass reactors

“…The only silicon-containing material present was the glass plasma reactor.In a typical experiment a sample of PP film was placed symmetrically in the center of the reaction chamber and the chamber was evacuated to the base pressure and then vacuumed (base pressure) and repressurized (20 mmHg) several times with argon in order to remove possible gas contaminants. Car-Stainless steel trap (liquid NJ 6 Coupling coil12 Vacuum pump Diagram of plasma nitrogen cold trap.…”