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Plasma Modification (plasma + modification)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Plasma Modification of PDMS Microfluidic Devices for Control of Electroosmotic Flow

PLASMA PROCESSES AND POLYMERS, Issue 4 2007
Ina T. Martin
Abstract Polydimethylsiloxane (PDMS) capillary electrophoresis microchips were modified using plasma-enhanced chemical vapor deposition (PECVD), resulting in modified electroosmotic flow (EOF) values. Octafluoropropane (C3F8) and acrylic acid (AA) plasmas were chosen as initial test systems for device modification. Argon plasma pretreatments were used to improve adhesion of the fluorocarbon (FC) and AA films. Contact angle measurements and X-ray photoelectron spectroscopy data demonstrated that the Ar/C3F8 plasma treatment of PDMS results in the deposition of a hydrophobic, crosslinked FC film, whereas the Ar/AA plasma treatment results in the deposition of a hydrophilic film with ionizable acid groups. The extent of plasma modification within the device channels was explored using scanning Auger microscopy and dye absorption measurements. EOF values were measured for plasma-treated chips as a function of pH, and aging studies were performed to determine the durability of the plasma treatments. Results show that EOF is decreased in Ar/C3F8 plasma-treated chips, and varies less with pH than untreated devices. Additionally, EOF measurements are constant for a minimum of 5 d. In contrast, EOF for Ar/AA plasma-treated devices is dependent on pH. EOF measurements of C3F8 and AA treated chips without the Ar pretreatment are less stable, particularly in the AA case. In addition to improving adhesion, the Ar plasma treatment results in a decreased hydrophobic dye absorption into the PDMS, which is attributed to the physical crosslinking of the polymer by the Ar plasma. [source]

Gold Coating of Poly(ethylene terephthalate) Modified by Argon Plasma

PLASMA PROCESSES AND POLYMERS, Issue 1 2007
Vladimír Kotál
Abstract Little information has been published concerning the interaction of gold with polymers. In the context of this lack of information, we decided to investigate the effect of Ar plasma treatment on the surface properties of poly(ethylene terephthalate) (PET) in order to examine its possible application for metal-polymer adhesion improvement. The plasma treatment leads to an immediate increase of the PET's surface wettability, which however significantly depends on the sample aging, more specifically on the time elapsed after the treatment. X-ray photoelectron spectroscopy (XPS) measurements revealed that the oxygen concentration in the surface-near layers increases as a result of the treatment, but that it also changes with time for the samples in contact with the atmosphere, probably as a result of polar group rearrangements. Plasma initiated ablation and Au sputtering increases the surface roughness. The nanoindenter measurements revealed that the treatment increases the microhardness of treated PET. Contrary to hardness, the elastic modulus decreases. Scratch tests showed that the deformation of samples consisting of Au coatings deposited on both pristine and treated PET was elastic rather than plastic. We conclude from the nanoindenter data that the plasma modification does not affect the adhesion of gold on PET, but the X-ray diffractometry (XRD) analysis showed that the Au film deposited on the as-treated PET, and on PET aged for 14 d are the most stable. [source]

Role of polymer chain end groups in plasma modification for surface metallization of polymeric materials

POLYMER INTERNATIONAL, Issue 6 2009
Norihiro Inagaki
Abstract How to improve adhesion between poly(oxybenzoate- co -oxynaphthoate) (Vecstar OC and FA films) and copper metal by Ar, O2, N2 and NH3 plasma modification was investigated. The mechanism of adhesion improvement is discussed from the viewpoint of chemical and physical interactions at the interface between the Vecstar film and copper metal layer. The adhesion between Vecstar OC film and copper metal was improved by chemical rather than physical interactions. Polymer chain end groups that occur at Vecstar OC film surfaces contribute effectively to adhesion. This improvement in adhesion is due to interactions between copper metal and OC groups formed by plasma modification. Aggregation of the OC groups to the copper metal/Vecstar OC film interface is a key factor for good adhesion. From this aspect, heat treatment of plasma-modified Vecstar OC films on glass plates is effective in the aggregation, and the peel strength for the copper metal/Vecstar OC film system reached 1.21 N (5 mm),1. Copyright © 2009 Society of Chemical Industry [source]

Study of adhesion and surface properties of low-density poly(ethylene) pre-treated by cold discharge plasma,

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 2 2007
Igor Novák
Abstract The low-density poly(ethylene), which is prone to hydrophilicity, dyeability, and bondability, was modified by surface barrier discharge and radio-frequency discharge plasma. A process of plasma modification was investigated to improve adhesion between poly(ethylene) and more polar polymers, to improve surface properties, and to form a new surface containing polar functional groups incoming to reactions with diazo-compounds, and/or vinyl silanes. The measurements of contact angles and peel strengths of adhesive joints were carried out for characterization of the surface and adhesive properties of the polymer modified by plasma. The topography of modified poly(ethylene) was studied using atomic force microscopy, and changes in chemical structure were analyzed with X-ray photoelectron spectroscopy. Copyright © 2006 John Wiley & Sons, Ltd. [source]