Energy of Reactions in Atmospheric-Pressure Plasma Polymerization with Inert Carrier Gas Bernard Nisol, Herv e Gagnon, Sophie Lerouge, Michael R. Wertheimer* A large reactor for performing dielectric barrier discharges (DBD) experiments at atmospheric pressure (AP) has been built and tested. The area of electrodes is more than 40 times greater than that of a small DBD cell, in which we have perfected a method formeasuring E g , the energy dissipated per cycle of the applied a.c. high voltage, V a (f). This methodology has been successfully applied to plasma polymerization experiments on the larger system, using volatile organic precursors (dopants) at ‰ concentrations in 10 standard liters per minute of argon (Ar). We measured DE g , the energy difference with and without dopant, for V a (f)  3 kV rms (20  f  40 kHz). From DE g we then derived E tot /N, the energy per molecule, and observed surprisingly good agreement with data published in the literature relating to low- pressure (LP) plasmas. 1. Introduction The literature regarding deposition of thin organic films for practical uses by plasma-enhanced chemical vapor depo- sition (PECVD), also known as plasma polymerization (PP), goes back at least to the early 1960s. [1] During intervening decades, literally thousands of articles devoted to this subject have been published worldwide, as well as numerous monographs. [2,3] While earlier literature almost exclusively dealt with high-frequency (h.f.: radiofrequency, r.f., or microwave) glow-discharge plasmas sustained at reduced pressure, typically near 100 mTorr (13.3 Pa), there has more recently been growing interest in PP based on gas discharges at atmospheric pressure (AP). [4–12] Dielectric barrier discharges (DBD) constitute the main approach that enables scale-up for industrial processing; of course, AP plasmas obviate the need for expensive vacuum systems, and they can, thereby, potentially reduce costs very significantly. DBD plasmas may be obtained in gaps between two electrode surfaces at least one of which is covered by a dielectric. They are non-equilibrium (cold) plasmas, useful in numerous plasma-chemical reactions beside PECVD, such as ozone synthesis, surface modifica- tion of polymers, abatement of pollutants, excimer lamps, and others. [13] In the PP literature, there has long been an interest in correlating deposition kinetics, physico-chemical and structural properties of films with energy absorbed by the organic precursor (so-called monomer) molecules in the plasma. Indeed, this often controversial subject has been the object of a series of debates in this journal; [14] Hegemann and coworkers [15–17] developed an original approach toward the macroscopic phenomenology of PP, one which leads to an unifying dependence of the mass deposition rate per unit of monomer flow, R m /F, on the macroscopic reaction parameter W/F (W being power input), by way of a quasi-Arrhenius expression R m =F ¼ G exp½E a =ðW=FÞ ð1Þ where E a is an apparent activation energy, and G a reactor- and process-dependent factor related to the maximum B. Nisol, H. Gagnon, M. R. Wertheimer Groupe des Couches Minces (GCM) and Department of Engineering Physics, Polytechnique Montr eal, Box 6079, Station Centre-Ville, Montreal, QC, Canada H3C 3A7 E-mail: michel.wertheimer@polymtl.ca S. Lerouge Research Centre, Centre Hospitalier de l’Universit e de Montr eal (CRCHUM), and Department of Mechanical Engineering,  Ecole de technologie sup erieure (  ETS), Montr eal, QC, Canada Full Paper Plasma Process. Polym. 2016, 13, 366–374 ß 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 366 DOI: 10.1002/ppap.201500068 wileyonlinelibrary.com