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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 23:06 |
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Conference: Bucharest University Faculty of Physics 2003 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Radiofrequency plasma polymerization process for composite layers deposition
Authors:
C. Petcu, S. Canulescu, S. Vizireanu, A. Lazea, D. Crintea, B. Mitu, G. Dinescu*
Affiliation:
National Institute for Lasers, Plasma and Radiation Physics
POBox MG 36-Magurele, 76900 Romania, *e-mail: dinescug@alpha1.infim.ro
E-mail
Keywords:
Abstract:
Plasma is a powerful tool for deposition of thin films and preparation of new materials. Particularly, radiofrequency fields, in which case the use of external electrodes is an advantage, can generate plasmas. This way the region where the material is deposited is not affected by the electrodes presence. In this contribution we report on the synthesis of a new composite polymeric material consisting of multilayers of plasma polymerized films and crystalline polymer particulates.
The used plasma reactor was a glass tube, 6 cm external diameter. Two annular external electrodes were mounted on the tube for sustaining a RF discharge. A rotary mechanical pump assured the pressure in the reactor, in the range 10-2-1 mbar, and argon was admitted in discharge via a flow controller. The dependence of breakdown and extinction of the discharge was studied upon electrodes position, gas pressure and RF power in order to establish the domains of stable operation.
In the usual Plasma Enhanced Chemical Vapor Deposition Systems vapors of liquid precursors are injected in plasma. Unlike that case, in order to obtain a composite material, we used a solid sublimating solid precursor, named di-para-xylylene (DPX); DPX is a solid crystalline dimer under normal conditions of temperature and pressure, and sublimates at temperatures above 150°C. An external oven mounted in the region were the DPX precursor, introduced in a small cylindrical glass ampoule, is placed generates DPX vapors. By applying the RF power, a discharge is generated in the Ar/DPX vapors, leading to deposition of plasma polymeric films. In the absence of the RF power, DPX is condensing on the surface, leading to deposition of particulates. The multilayers were obtained by switching on and off the RF discharge, at constant sublimation rate.
The obtained material, with structural gradient, was studied by FTIR and AFM measurements. It may be useful as keeping charge material in electrets or as interlayer in liquid crystal displays.
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