DI-UMONS : Dépôt institutionnel de l’université de Mons

Recherche transversale
(titres de publication, de périodique et noms de colloque inclus)
2013-09-11 - Colloque/Présentation - communication orale - Anglais - 12 page(s)

Ershov Sergey , Khelifa Farid , Dubois Philippe , Snyders Rony , " Impact of the chemical structure of the precursor on the plasma polymer’s free radical generation and stabilization" in 19th International Vacuum Congress (IVC), Paris, France, 2013

  • Codes CREF : Chimie des surfaces et des interfaces (DI1327), Chimie des polymères de synthèse (DI131C), Physique des plasmas (DI1233)
  • Unités de recherche UMONS : Chimie des interactions plasma-surface (S882)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
  • Centres UMONS : Centre d’Innovation et de Recherche en Matériaux Polymères (CIRMAP)
Texte intégral :

Abstract(s) :

(Anglais) Plasma polymerized films (PPF) synthesized by plasma enhanced chemical vapor deposition (PECVD) find increasing applications in various fields (microelectronics, biomedicine, etc.) and differ in many ways from conventional polymers. One of the most specific properties of the PPF is the high reactivity of its surface rich in free radicals arising from deposition mechanism. Although generally considered as a disadvantage leading to the ageing of the PPF, reactivity of the plasma treated polymers and PPF surfaces can be beneficially employed, for example, for grafting of a specific chemical functionality. The quantitative evaluation of the surface radical density in the PPF as well as the understanding of radical formation mechanisms are thus considered to be mandatory for a successful surface modification. The aim of this work is to compare the free radicals concentration and formation mechanisms in PPF synthesized from a saturated cyclic precursor and its resonant isomer in order to evaluate the impact of aromaticity on radical generation. The surface radical densities of the isopropanol-, benzene- and isopropanol-based PPF have been quantitatively determined by a combination of NO chemical derivatization and X-ray Photoelectron Spectrosopy (XPS). Once derivatization conditions were optimized on the isopropanol-based PPF, the radical density, derived from at.% N determined by XPS, was evaluated and compared between the benzene- and cyclohexane-based PPF as a function of deposition power. As an example, for isopropanol, it has been found out that the surface density of free radicals presents a maximum for the deposition power of 200 W (~1.6 • 1014 spin/cm²) and it stabilizes (~1.45 • 1014 spin/cm²) with further power increase. XPS findings are supported by in situ FTIR measurements that provided extra information about the degree of plasma fragmentation yielding fragmentation saturation for a deposition power of 200 W. Finally, some preliminary chemical grafting experiments allowed to cross-check the relevance of derivatization results.