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It has been demonstrated that surfaces coated with poly(ethylene glycol) (PEG) are capable of reducing protein adsorption, bacterial attachment, and biofilm formation. In this communication cold-plasma–enhanced processes were employed for the deposition of PEG-like structures onto stainless steel surfaces. Stainless steel samples were coated under 1,4,7,10-tetraoxacyclododecane (12-crown-4)–ether and tri(ethylene glycol) dimethyl ether (triglyme)–radio frequency (RF)–plasma conditions. The chemistry and characteristics of plasma-coated samples and biofilms were investigated using electron spectroscopy for chemical analysis (ESCA), atomic force microscopy (AFM), and water contact angle analysis. ESCA analysis indicated that the plasma modification resulted in the deposition of PEG-like structures, built up mainly of –CH2CH2O– linkages. Plasma-coated stainless steel surfaces were more hydrophilic and had lower surface roughness values compared to those of unmodified substrates. Compared to the unmodified surfaces, they not only significantly reduced bacterial attachment and biofilm formation in the presence of a mixed culture of Salmonella typhimurium,Staphylococcus epidermidis, and Pseudomonas fluorescens but also influenced the chemical characteristics of the biofilm. Thus, plasma deposition of PEG-like structures will be of use to the food-processing and medical industries searching for new technologies to reduce bacterial contamination. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3425–3438, 2001

Polyester (PET) swatches are treated with an electrical discharge plasma of a reactive atmosphere (tetrachlorosilane) to graft chlorosilane groups, subsequently hydrolyzed to very hydrophilic hydroxysilane groups. The Kawabata evaluation system for fabrics (KES-FB), high resolution microscopy, and surface tension measurements are used to investigate the physical properties of the fabrics before and after plasma exposure. The results show that the surface parameters are considerably modified by the treatment.

It is known that for creating advanced polyolefin/cement-based composites the polymer surface should be converted into a layer which is compatible with the inorganic component. In this respect, plasma chemistry offers additional solutions to the wet chemistry approach. It has been demonstrated during the last decade that cold plasma-mediated reactions are suitable for etching and surface functionalizing even the most inert polymeric substrates, including Teflon, polypropylene (PP), and polyethylene (PE). In this paper composite preparations from SiCl4-cold plasma and chromic acid-treated fibrillated PP substrates and cement are described. The nature of plasma- and wet chemistry-induced surface functionalization and etching processes was monitored using survey and high-resolution X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), and dynamic water contact angle measurements. It has been demonstrated that th...

Summary A novel plasma-enhanced coating for wood substrates has been developed which diminishes the degradation of wood under simulated harsh environmental conditions. Reflective (zinc oxide) and electromagnetic radiation (EMR)-absorbent (benzotriazole, 2-hydroxybenzophenone, phtalocyanine, and graphite) substances were incorporated into a liquid phase, high-molecular-weight polydimethylsiloxane and deposited as thin layers on wood surfaces. The macromolecular films, containing the dispersed materials, were then converted into a three-dimensional solid state network by exposure to a 30 kHz-oxygen-RF-plasma. The discharge induced chemistry and altered surface topographies in the surface layers were monitored by survey and high resolution Electron Spectroscopy for Chemical Analysis, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy. The surface characteristics and the resistance to weathering of the plasma treated substrates were evaluated and compared to the properties of un-modified samples.

Summary Southern yellow pine wood surfaces were modified under cold plasma conditions in order to create water repellent characteristics. The surface chemistry of the plasma “polymerized” hexamethyldisiloxane (PHMDSO) deposited onto wood surfaces was investigated using Electron Spectroscopy for Chemical Analysis (ESCA) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). The presence of a crosslinked macromolecular structure, based on Si-O-Si and Si-O-C linkages was detected. Pyrolysis Mass Spectroscopy (MS) was carried out to investigate the nature of the building blocks of the plasma generated macromolecular structure. Plasma modified samples exhibited very high water contact angle values (contact angle = 130 degrees) in comparison to the unmodified samples (contact angle ≤ 15 degrees), indicating the presence of a hydrophobic surface. Atomic Force Microscopy (AFM) images, collected both from unmodified and HMDSO-plasma modified samples, indicate the progressive growth of the plasma “polymer”, resulting in the deposition of a smooth layer at 10 minutes treatment time. Differential Thermal Analysis (DTA) indicated high thermal stability of the PHMDSO.

Isobutylene was polymerized by Si2Cl6-RF-plasma-generated silylium ions. Initiation is due to Cl x Si+ in-situ adsorbed on frozen isobutylene surfaces at liquid nitrogen temperature. The polymerization of isobutylene occurs in the absence of counterions. According to survey and high resolution ESCA spectra, silicon is present in the resulting polymers, which suggests initiation by Cl x Si*. FT-IR, 1H- and 13C-NMR spectroscopies, GC-MS, high resolution pyrolysis MS, as well as FAB and FI-MS analyses indicate that plasma-polymerized isobutylenes are linear oligomers of broad molecular weight distribution. DTA-TG analyses substantiate the conclusion that the average molecular weight of plasma-polymerized isobutylene is low. The findings demonstrate the usefulness of RF-plasma for generating silylium ions and silylium ions-mediated cationic polymerization. The possibility of producing novel polyisobutylene/polysiloxane block copolymers is suggested.