Plasma diagnostics were performed during excimer laser ablation of graphite in a low-pressure atmosphere using time- and space-resolved optical emission spectroscopy. The laser fluence and nitrogen pressure were set to values typically applied to pulsed laser deposition of thin films. Under these conditions, optical emission spectra were dominated by continuum emission and spectral lines from carbon ions during the early plasma phase , when the carbon vapour is located in the vicinity of the target surface, whereas molecular bands of molecules and CN radicals were essentially observed at later times when the vapour expands through the ambient gas. Emission spectra of , CN and were recorded as functions of time for various distances from the target. From computer simulations of molecular spectra, we deduced rotational and vibrational temperatures. The acquired information about the kinetics of excited plasma species and gas phase reactions contributes to a better understanding of pulsed laser deposition of carbon nitride thin films.
Plasma polymerized allylamine (ppAA) films were deposited in a radio‐frequency glow discharge plasma reactor using a continuous‐wave mode and varying the discharge power from 15 to 125 W. The deposition rate reached 26 nm · min−1 and was constant within at least half an hour of process. The chemical structure and elemental composition of the deposited films were investigated by Fourier transform infrared and X‐ray photoelectron spectroscopies, whereas surface properties were analyzed by atomic force microscopy and surface free energy measurement. A special focus is given to the stability of ppAA in aqueous media and primary amine quantification. The use of fluorescent microscopy and UV‐Visible spectroscopy enabled us to detect and quantify the primary amine, respectively. All the studied parameters varied widely with enhanced power with a transition point around 50 W. Over this value, the results remain relatively unchanged.
A far cold remote nitrogen (FCRN) plasma, eventually doped with oxygen, was used to modify the surface properties of a polyethylene (PE) powder. The process associates both remote plasma and fluidized bed technologies. Two applications are described. The first one, for increasing the hydrophilic character of PE, only requires a single plasma treatment. The second application involves FCRN plasma polymerization of 1,1,3,3-tetramethyldisiloxane mixed with oxygen to obtain a hydrophobic film on the powder surface. The wettability evolution of the PE powder was followed by contact angle measurements (Washburn method) versus different experimental parameters. The surface modifications induced by the treatments were studied by XPS.
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