Plasma Polymerization of a Saturated Branched Hydrocarbon. The Case of Heptamethylnonane Caroline De Vos,* Nicolas Vandencasteele, Alexandros Kakaroglou, Bernard Nisol, Iris de Graeve, Guy Van Assche, Bruno Van Mele, Herman Terryn, Franc ¸ois Reniers 1. Introduction Plasma polymerization is a suitable method to deposit thin organic coatings on various substrates. Nowadays there has been a growing interest in the development of atmospheric plasma especially for industrial applications in order to avoid expensive vacuum pumping systems and to imple- ment plasma into continuous processes. [1] Plasma polymers have characteristic properties that may differ significantly from conventional polymers. It is generally reported in the literature that their chemical structure is more random and more cross-linked than conventional polymers. [2] Plasma-polymerized films are usually amorphous, pinholes-free, and highly resistant to heat. [3] They also present good barrier properties and a good adhesion to most of substrates like polymers, glass, and metals. Plasma polymerization is an environmentally friendly technique due to the lack of necessity for solvents and the low temperature of process. Moreover it reduces the number of steps as it can integrate the cleaning, the etching of the substrate and the deposition of the coating in one step. The properties of the coating such as the thickness, the morphology, the chemical composition, or the film structure can be tailored by modifying the experimental parameters of the discharge. [4,5] Unlike the conventional polymerization, plasma poly- merization does not require either the presence of an unsaturated molecule as precursor or the presence of a particular active site. [6] This is probably due to the initiation step. In plasma polymerization, it is generally accepted that the precursor is fragmented by bond breaking, leading to Full Paper C. De Vos, N. Vandencasteele, B. Nisol, F. Reniers Faculty of Sciences – Analytical and Interfacial Chemistry, Universite ´ Libre de Bruxelles, 2, bd. du Triomphe, CP 255, B1050 Brussels, Belgium E-mail: cardevos@ulb.ac.be A. Kakaroglou, I. de Graeve, H. Terryn Research Group Electrochemical and Surface Engineering (SURF), Department of Materials and Chemistry (MACH), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium G. Van Assche, B. Van Mele Research Group Physical Chemistry and Polymer Science, Department of Materials and Chemistry (MACH), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium 2,2,4,4,6,8,8-Heptamethylnonane (HMN), a saturated branched hydrocarbon precursor, is deposited by means of atmospheric plasma DBD. Hydrophobic coatings starting from this precursor which is liquid at room temperature can be obtained. The degree of polymerization of the coating seems to be dependent on the amount of provided precursor. The coatings were characterized by FTIR, TOF-SIMS, WCA, SE, and XPS. Plasma Process. Polym. 2013, 10, 51–59 ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com DOI: 10.1002/ppap.201200023 51