A direct comparison between gas state and atomised liquid state precursor in the deposition of functional coatings by pin corona plasma

¹ Plasma Ireland, 22 Summerhill North, Cork, Ireland
² Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20618 Lublin, Poland

^a e-mail: therbert@irishprecisionoptics.com

Received: 14 November 2010
Accepted: 21 December 2010
Published online: 21 July 2011

Abstract

An atmospheric pressure non-thermal equilibrium pin corona plasma jet was used to deposit polymeric coatings from monomer precursor in both vapour and liquid aerosol states to allow a direct comparison of the quality and performance of the as-deposited coatings, specifically with respect to the achievement of soft plasma polymerisation (SPP) where the coating exhibits minimal fragmentation or damage to the monomer molecule while, at the same time, being highly cross-linked. A long chain perfluorocarbon molecule was introduced into the helium plasma and coatings deposited at rates of up to 50 nm/min. XPS, FTIR, contact angle and ellipsometric measurements indicated that a controlled polymerisation reaction had taken place in the case of the vapour deposited samples through the vinyl group of the monomer, with only minor fragmentation of the functional perfluoro chain. Furthermore, a high level of cross-linking was achieved and the coatings were stable to a toluene wash. In contrast, while the liquid deposition samples showed good retention of monomer molecular structure, they exhibited negligible cross-linking and were readily removed by immersion in toluene rendering them functionally useless.