One Step Polymerization of Sulfonated Polystyrene Films in a Dielectric Barrier Discharge (original) (raw)
Related papers
Influence of operational parameters on plasma polymerization process at atmospheric pressure
Journal of Applied Physics, 2010
In this paper, a dielectric barrier discharge working at atmospheric pressure has been used in order to investigate the plasma polymerization reactions using styrene vapors. The macroscopic parameters were carefully chosen in order to obtain polymer thin films with high deposition rate and high concentration of activated species consequently. Thus, the plasma polymerization processes can be described considering the dependence of polymer deposition rate by monomer flow rate and discharge power. The domains of plasma polymerization reactions were identified and the optimum operating conditions were obtained at a maximum deposition rate of 3.8 nm/s ͑discharge power: 7.5 W͒. Different techniques of analysis were used to identify the chemical composition of plasma polystyrene films and the domains of polymerization reaction. The film thickness was measured by optical interferometry and the chemical composition was analyzed by Fourier-transform infrared spectroscopy, UV spectroscopy, and x-ray photoelectron spectroscopy.
Morphology of polystyrene films deposited by RF plasma
Journal of Microscopy, 2007
A new plasma reactor, set up with a large planar inductively coupled source, is used for the first time to deposit a polymer coating (pPS) from a styrene monomer. This work is devoted to the relationship between external plasma parameters and substrate topography, and pPS coating morphology, which is investigated by scanning electron microscopy and atomic force microscopy. Stainless steel, gold and glass surfaces are used as substrates. It is clearly demonstrated that the film morphology can be controlled by adjustment of RF input power, pressure. The analysis performed further reveals that the pPS film's characteristics strongly depend on the substrate topography and its electrical potential during the discharge. Finally, the plasma duration also strongly influences the morphology of the films. The morphologies obtained include smooth films without any specific feature, worm-like structures, particles (nanometer-and micrometer-sized) associated along preferential directions and randomly distributed particles (micrometer-sized). The intrinsic topography of the substrate influences the film structure in the case of thin films (thickness lower than about 100 nm). Polymerization is suggested to take place at the surface in contact with the discharge rather than in the gas phase. Nucleation and growth start preferentially on substrate defects such as polishing scratches.
The Open Plasma Physics Journal, 2013
Atmospheric pressure plasma co-polymerization of ethylene glycol and styrene was applied to produce poly (ethylene glycol-co-styrene) using a dielectric barrier discharge. The chemical structure of polymerized films was studied by Fourier-transform infrared spectroscopy which confirms that we obtained copolymerized films with hydroxyl groups incorporated. Chemical composition of films was studied by X-ray Photoelectron Spectroscopy and oxygen containing groups (C-O and C=O) were identified. Topography of polymer films was revealed using Atomic Force Microscopy technique and the film root mean square roughness (R rms) was found to be 1.6 nm. Surface wettability was analyzed using water contact angle technique.
Langmuir, 2010
Polystyrene (PS) surfaces were treated by electron-beam-generated plasmas in argon/oxygen, argon/nitrogen, and argon/sulfur hexafluoride environments. The resulting modifications of the polymer surface energy, morphology, and chemical composition were analyzed by a suite of complementary analytical techniques: contact angle goniometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and reflection electron energy loss spectroscopy (REELS). The plasma treatments produced only minimal increases in the surface roughness while introducing the expected chemical modifications: oxygen-based after Ar/O 2 plasma, oxygen-and nitrogen-based after Ar/N 2 plasma, and fluorine-based after Ar/SF 6 plasma. Fluorinated PS surfaces became hydrophobic and did not significantly change their properties over time. In contrast, polymer treated in Ar/O 2 and Ar/N 2 plasmas initially became hydrophilic but underwent hydrophobic recovery after 28 days of aging. The aromatic carbon chemistry in the top 1 nm of these aged surfaces clearly indicated that the hydrophobic recovery was produced by reorientation/diffusion of undamaged aromatic polymer fragments from the bulk rather than by contamination. Nondestructive depth profiles of aged plasma-treated PS films were reconstructed from parallel angle-resolved XPS (ARXPS) measurements using a maximum-entropy algorithm. The salient features of reconstructed profiles were confirmed by sputter profiles obtained with 200 eV Ar ions. Both types of depth profiles showed that the electron-beam-generated plasma modifications are confined to the topmost 3-4 nm of the polymer surface, while valence band measurements and unsaturated carbon signatures in ARXPS and REELS data indicated that much of the PS structure was preserved below 9 nm.
The European Physical Journal Applied Physics, 2002
This paper is devoted to polystyrene thin film treatment under DC pulsed discharges in nitrogen, oxygen and oxygen-argon mixtures. XPS analysis is used in order to investigate the new chemical bonds generated by the reactive particles colliding the surface from the plasma. The experimental conditions are close to the best running conditions deduced from [16, 75, 86]. Correlations between microscopic analyses obtained by XPS through the knowledge of the surface chemical composition and macroscopic ones realized by studies of water drop deposited on the films (contact angle measurements) are presented. It is pointed out that the wettability is highly improved when the percentage of oxygen atoms incorporated in polystyrene surface reaches a high value. CO , C = O and O-C = O are the main chemical bonds and it is found that the oxygen uptake happens during a very short time (about one second for the treatment duration time, i.e. about 10 ms on account of the duty factor value). A high oxygen rate is observed, correlated to the formation of a maximum ∆θ/θi plateau value (wettability). Reaction processes in the plasma bulk and on the polystyrene surface are proposed, taking into account the bond energies of polystyrene. As a consequence, the polystyrene treatment is interpreted assuming two steps for the reaction processes: in a first step, chemical bonds are broken by energy transfer from reactive particles to the surface and in a second step, new chemical bonds are generated. In this spirit, the main reactive plasma particles are described and surface reactions are proposed on the polystyrene surface.
Modification of plasma polymer films by ion implantation
2004
In this work, thin polymer films were prepared from acetylene and argon radiofrequency (13.56 MHz, 80 W) glow discharges. Post-deposition treatment was performed by plasma immersion ion implantation in nitrogen or helium glow discharges (13.56 MHz, 70 W). In these cases, samples were biased with 25 kV negative pulses. Exposure time to the bombardment plasma, t, ranged from 900 to 7200 s. Chemical composition of the film surfaces was investigated by X-ray Photoelectron Spectroscopy and the resistance to oxidation by the etching process, in reactive oxygen plasmas. Oxygen and nitrogen were detected in all the samples. While the concentration of the former continuously changed with t, that of N kept practically constant in small proportions. The film is predominantly formed by sp 2 states, but the proportion of sp 3 hybridization slightly increased with t. The etching rate dropped under certain conditions of nitrogen bombardment whereas helium implantation has not significantly improved it. These results are ascribed to the crosslinking degree of the polymeric chains, ruled by the total amount of energy delivered to the film.
Surface Evaluation of Plasma-Modified Polysulfone (Udel P-1700) Films
The paper presents a new method for the evaluation of surface properties. Polysulfone films modified by plasma treatment in carbon dioxide, nitrogen, and vapors of n-butylamine were taken as test samples. Surface concentrations of acidic or basic functionalities were estimated by contact angle measurements. Aqueous solutions of HCl and NaOH with various pH values were used. The method of surface evaluation is based on fitting the γLcosΘ versus pH (or pOH) relationship with a polynomial and finding its inflection point. The pH (or pOH) values at this point are recalculated into apparent surface concentrations of basic (or acidic) functionalities by means of Gibbs' and Langmuir's equations. It was found that surfaces contain acidic functionalities (0.15 µmol/m 2) when polysulfone was modified in carbon dioxide and basic functionalities (2.50 µmol/m 2) for butylamine plasma. Modification with N2 resulted in the creation of an amphoteric surface.
Polystyrene thin films treatment under DC pulsed discharges conditions in oxygen
European Physical Journal-applied Physics, 2001
This paper is devoted to atactic polystyrene (aPS) thin films treatment under DC pulsed discharge in nitrogen. The experiments were performed using a symmetrical plane-to-plane of electrodes configuration in order to improve the treatment homogeneity and also to compare the treatment efficiency when the aPS is on the cathode or on the anode. During these experiments, the pressure and the electrical conditions were maintained unchanged. The experimental results were compared for the two positions of samples, when the gap length and the afterglow duration time were varied. It appears that the treatment depends on the sample position and an interpretation is proposed. The physical conditions and the reaction processes in the plasma bulk and on the aPS surface were analysed in order to understand their influence on the surface treatment. The importance of metastables is pointed out and it is deduced that these long-life excited states are firstly produced near the anode and fill the gap following the evolution and distribution of the electron current density.
Plasma Polymerization: Electronics and Biomedical Application
Plasma Science and Technology for Emerging Economies, 2017
Polymer thin films have received great interest in recent past because of their wide range of physical, chemical, mechanical, electrical and biological properties, which make them well suited for innumerable applications in fields of mechanics, optics, and electronics [1-3]. Polymer thin films can be fabricated using a variety of methods. Based on the nature of the fabrication process, these methods can be broadly divided into two categories: "wet" solution-based processing, e.g., spin coating and dip coating, or "dry" methods, e.g., physical vapor deposition (PVD) and chemical vapor deposition (CVD). Plasma polymerization is a type of CVD used extensively to synthesize polymer thin films from organic and inorganic precursors, where plasma discharge is used to catalyze the chemical reactions leading to formation of the polymer structure [4, 5]. Hence, plasma polymers can be generally defined as thin films of material which are formed as a result of interaction of monomer (organic and inorganic) vapor in the plasma (glow) discharge [6]. Although the word polymer is used, this special class of material differs from conventional polymers in several respects. Most notably, plasma polymers generally lack regular repeating unit, their chains are often short, randomly branched, and highly cross-linked. As the result of their unique chemical structure, these polymers generally do not exhibit distinct glass transition temperatures and have high elastic moduli, excellent mechanical, thermal and chemical stability, and outstanding adhesion to a variety of substrates [5]. Their chemical composition and thickness can be easily controlled by controlling the deposition parameters and the nature of