Chemical surface modification of polymethylmethacrylate (PMMA) and polypropylene (PP) particles was achieved using a continuous atmospheric plasma process, resulting in increased oxidation and hydrophilicity. Contact angles of treated PMMA ranged from 79–117° (125° for untreated). Air plasma produced higher contact angles than pure nitrogen, which is attributed to primary surface degradation from oxygen. Higher energy and flow rate of water resulted in decreased contact angles. Treated PP mixed in water upon agitation, while untreated PP remained at the surface. X‐ray photoelectron spectroscopy (XPS) showed increased CO and CO for treated samples. The addition of 10% hydroxyethylmethacrylate (HEMA) to water showed a slight decrease in contact angle, but no difference from pure water in XPS results.

The plasma deposition behavior of hexamethyldisiloxane (HMDSO) and decamethylcyclopentasiloxane (D5) is investigated for an atmospheric pressure plasma jet. The energy-deficient and monomer-deficient domains are revealed by normalized parameters and no significant difference between HMDSO and D5 is observed. The results are supported by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy. The data is also evaluated using an Arrhenius-type equation and an empirical equation reported in the literature, but the correlation is not as good as the normalized parameters. Changes in Si-O-Si bonding arrangements are analyzed by deconvolution of the FTIR absorbance band, showing an increase in porous cage structures with higher normalized energy input. monomer-deficient domain porous cage structures of Si-O-Si bonding network structures of Si-O-Si bonding e n e rg y -d e fi c ie n t d o m a in GR/FM W/FM K E Y W O R D S deposition characterization, infrared spectroscopy, organosilicon precursors, plasma polymerization, plasma-enhanced chemical vapor deposition Plasma Process Polym. 2019;16:e1900024 www.plasma-polymers.com

The focus of this paper is the investigation of reduced graphene oxide (GO)/nickel foam (RGON) samples for use as supercapacitor electrodes. Nickel foam samples were soaked in a GO suspension and dried before being subjected to two different methods to remove oxygen. Atmospheric pressure annealed (APA) samples were treated with a varying number (10–18) of nitrogen plasma jet scans, where sample temperatures did not exceed 280 °C. Furnace annealed (FA) samples were processed in an atmosphere of hydrogen and argon, at temperatures ranging from 600 °C to 900 °C. Environmental Scanning Electron Microscope (ESEM) data indicated that the carbon to oxygen (C:O) ratio for APA samples was minimized at an intermediate number of plasma scans. Fourier Transform Infrared Spectroscopic (FTIR) and Raman spectroscopic data supported this finding. ESEM analysis from FA samples showed that with increasing temperatures of annealing, GO is transformed to reduced graphene oxide (RGO), with C:O ratios exceeding 35:1. X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD) data indicated the formation of RGO with an increasing annealing temperature until 800 °C, when oxygen reincorporation in the surface atomic layers becomes an issue. Supercapacitors, constructed using the FA samples, demonstrated performances that correlated with surface atomic layer optimization of the C:O ratio.

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