Over the last ten years, expansion of atmospheric pressure plasma solutions for surface treatment of materials has been remarkable, however direct plasma technology for thin film deposition needs still great effort. The objective of this paper is to establish the state of the art on scientific and technologic locks, which have to be opened to consider direct atmospheric pressure plasma‐enhanced chemical vapor deposition (AP‐PECVD) a viable option for industrial application. Basic scientific principles to understand and optimize an AP‐PECVD process are summarized. Laboratory reactor configurations are reviewed. Reference points for the design and use of AP‐PECVD reactors according to the desired thin film properties are given. Finally, solutions to avoid powder formation and to increase the thin film growth rate are discussed.

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A facile atmospheric pressure cold plasma process is presented to deposit a novel organic-inorganic hydrocarbon polymer/ZnO nanoparticles nanocomposite coating. Specifically, this method involves the utilization of an atmospheric pressure dielectric barrier discharge (DBD) fed with helium and the aerosol of a dispersion of oleate-capped ZnO nanoparticles (NPs) in n-octane. As assessed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, the deposited nanocomposite coating combines the chemical features of both the oleate-capped ZnO NPs and the polyethylene-like organic component originated from the plasma polymerization of n-octane. Additionally, scanning electron microscopy (SEM) and transmission scanning electron microscopy (TSEM) confirm the synthesis of hierarchical micro/nanostructured coatings containing quasi-spherical NPs agglomerates. The polyethylene-like polymer covers the NPs agglomerates to different extents and contributes to their immobilization in the three-dimensional network of the coating. The increase of both the deposition time (1-10 min) and the NPs concentration in the dispersion (0.5-5 wt %) has a significant effect on the chemical and morphological structure of the thin films and, in fact, results in the increase the ZnO NPs content, which ultimately leads to superhydrophobic surfaces (advancing and receding water contact angles higher than 160°) with low hysteresis due to the hierarchical multiscale roughness of the coating.

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In this paper, we describe the deposition of PEO‐like coatings using dielectric barrier discharges (DBDs) fed with aerosols of the TEGDME organic precursor in helium. By properly tuning plasma parameters such as aerosol/carrier flow ratio, frequency of the electric field applied and input power, the deposition process could be modulated to obtain coatings with variable PEO character, from 50% (cell adhesive) to 70% (nonfouling), which are interesting for surface modification of biomaterials and biomedical devices.

The thin film deposition in DBDs fed with Ar/HMDSO/O2 mixtures was studied by comparing the FT‐IR spectra of the deposits with the GC‐MS analyses of the exhaust gas. Under the experimental conditions investigated, oxygen addition does not enhance the activation of the monomer while it highly influences the chemical composition and structure of the deposited coating as well as the quali‐quantitative distribution of by‐products in the exhaust. Without oxygen addition a coating with high monomer structure retention is obtained and the exhaust contains several by‐products such as silanes, silanols, and linear and cyclic siloxanes. The dimethylsiloxane unit seems to be the most important building block of oligomers. Oxygen addition to the feed is responsible for an intense reduction of the organic character of the coating as well as for a steep decrease, below the quantification limit, of the concentration of all by‐products except silanols. Some evidences induce to claim that the silanol groups contained in the deposits are formed through heterogeneous (plasma‐surface) reactions.

The synthesis of composites thin films made by injecting an aerosol suspension of 20 nm‐size TiO2 nanoparticles (NPs) and isopropanol (IPA) in a filamentary argon Dielectric Barrier Discharge (DBD) is studied as a function of the DBD frequency from 1 to 50 kHz. The plasma is modulated to get homogeneous coatings. The deposition rate and morphology of the composite thin films are determined from SEM images of both surface and cross section. Their chemical composition is investigated by XPS, Raman spectroscopy and FTIR measurements. The structural composition of the NPs is examined by XRD. All the deposited composites show the chemical signature of the NPs as well as of the polymer‐like coating resulting from the plasma polymerization of IPA. No mixed phase is observed and the sizes of the NPs as well as of their aggregates are not affected by the plasma. With this method aerosol droplets are evaporated before entering the plasma and the NPs inside a same droplet are aggregated. Results show that the DBD frequency controls the composite composition by independently influencing the NPs transport and the matrix growth rate. At 1 kHz, the coating is essentially made of NPs with a low carbon coating. From 1 to 50 kHz, the Ti/C ratio is divided by two orders of magnitude. As the frequency increases the quantity of NPs decreases and since 10 kHz the matrix thickness increases. The decrease of the NPs is explained by the numerical modeling of the NPs trajectory. It is found that from 10 to 1 kHz, the lower is the frequency, the higher is the transport of the NPs to the surface due to the electrostatic force. On the other hand the matrix growth rate increases from almost zero at 10 kHz up to 19 nm · min−1 at 50 kHz because of the linear increases of the DBD power with the frequency.

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