			Home About us Contact

Ar Plasma (ar + plasma)

Distribution by Scientific Domains

Polymers and Materials Science	75%

Selected Abstracts

Plasma-induced graft polymerization of poly(ethylene glycol) on poly(methyl methacrylate) surfaces for improving antistatic property

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2010
Yanlin Wei
Abstract Ar plasma-induced graft polymerization of poly(ethylene glycol) (PEG) on Ar plasma pretreated poly(methyl methacrylate) (PMMA) surfaces was carried out to improve the antistatic properties. The surface composition and microstructure of the PEG-grafted PMMA surfaces from plasma induction were characterized by attenuated total reflectance Fourier transfer infrared (ATR-FTIR) spectroscopy, water contact angles (CA), and atomic force microscopy (AFM) measurements. The measurements revealed that the antistatic properties can be remarkably improved with the surface resistivity of PEG-grafted PMMA surface decreasing significantly by 3,6 orders of magnitude, with the optimum condition for polymerization grafted onto the Ar plasma pretreated PMMA surface being 40 W for RF power and 3 min for glow discharge time. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

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]

A Nonequilibrium, Atmospheric-Pressure Argon Plasma Torch for Deposition of Thin Silicon Dioxide Films

CHEMICAL VAPOR DEPOSITION, Issue 4 2007
P. Kasih
Abstract A nonequilibrium, atmospheric-pressure plasma torch that can be generated either in He or Ar gas by using a pulsed high-voltage power supply with the discharge temperature in the range 22,35,°C has been developed. This system is used to deposit silicon dioxide films from a hexamethyldisiloxane (HMDSO) precursor diluted in an oxygen carrier gas. It is concluded that, in terms of both quality and deposition rate at the same applied power, frequency, and gas composition, Ar plasma is more powerful than He plasma for depositing SiO2 -like films. The maximum feed rate of HMDSO/O2 injected into the Ar plasma torch is limited to 100,mL,min,1 to ensure inorganic coatings are deposited. In order to improve the visual quality, without adversely affecting the inorganic features of the film, a small amount of nitrogen (N2) can be added to the Ar as a working gas. When the ratio of Ar to N2 in the flow gas is 30:1, the discharge behavior is transformed from filamentary to glowlike as a result of the quenching effect of admixed N2 on Ar plasma. [source]

Dry etching of N-face GaN using two high-density plasma etch techniques

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2007
F. Rizzi
Abstract This paper describes processing of GaN on the on the (000) N-face surface, using two different high-density plasma etch techniques, inductively coupled plasma (ICP) etch, and electron cyclotron resonance (ECR) etching. ICP experiments used several different conditions employing Cl2,Ar,BCl3 or Cl2,Ar plasmas. The resulting maximum etch rates of 370,390 nm/min are approximately twice as high as etch rates for Ga-face (0001) GaN with the same recipes. ECR etching employed a Cl2,CH4,Ar recipe, which produced an average etch rate of 55 nm/min in a 20-minute etch process on N-face GaN. Both etch techniques increased the roughness of N-face GaN, but could produce surfaces with average roughness values below 3 nm. Selection of conditions with a dominant chemical etch contribution is important to maintain smooth surfaces. The use of both ICP and ECR etching in sequence is advantageous in situations where a GaN substrate several tens of microns in thickness must be thinned from the backside, stopping the etch in a suitable marker layer. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]