The following articles, papers and publications discuss growing fields of research in Atmospheric Plasma Treatment of MEMS, Nanomaterials, Microarrays and Lab on a Chip. The field is relatively new and publications are being added all the time so check back frequently for updates. Organic (carbon-based) nanomaterials such and carbon nanotubes (CNT) and graphene cleaning and activation as well as MEMS and Microfluidics manufacturing and assembly including Polydimethylsiloxane (PDMS) functionalization and glass cleaning are just some of the atmospheric plasma treatments applications we have addressed.
Atmospheric Plasma Treatment of MEMS, Nanomaterials, Microarrays and Lab on a Chip related publications are listed below. Contact us to receive a complimentary copy. Please reference the authors and publication number in your email request (copy and paste into your email response).
- S. M. Hong, S. H. Kim, J. H. Kim and H. I. Hwang., “Hydrophilic Surface Modification of PDMS Using Atmospheric RF Plasma”, Journal of Physics Conference Series 01/2006; 34. DOI: 10.1088/1742-6596/34/1/108. Abstract: Control of surface properties in microfluidics systems is an indispensable prerequisite for the success of bioanalytical applications. Poly(dimethylsiloxane) (PDMS) microfluidic devices are hampered from unwantedadsorption of biomolecules and the lack of methods to control electroosmotic flow(EOF). Among the various methods of hydrophilic treatment, a new cleaner technology was chosen to treat PDMS. By using atmospheric RF plasma, hydrophilic surfaces can be created. Thus, analysis was conducted with AFM, XPS, and contact angle before and after plasma treatment. Constructing hydrophilic surfaces without changing the true character of that surface has previously been costly and time consuming. But by using atmospheric plasma cost and time are both greatly reduced. There are many other benefits of hydrophilic surface treatment, including the capability to increase adhesion and capillary effects, etc. Also, with hydrophilic treatment of the micro channels
on the PDMS surface, surface tension is reduced thus allowing fluids to move easily along those channels. However, the most important aim is to increase the capillary effects without any deposition or chemical treatment. - Lee, S., Peng, J. W., and Liu, C. H., “Raman study of carbon nanotube purification using atmospheric pressure plasma,” Carbon 46, 2124 (2008). Abstract: Multiwalled carbon nanotubes (MWCNTs) were treated with an atmospheric pressure plasma source using an argon/water mixture. Optical emission diagnostics has shown that hydroxyl radicals (OH) were the major reactive species in the plasma. The structural changes in MWCNTs were monitored by micro-Raman spectroscopy. The observed variation of the D and G band intensity ratio and position dispersion with plasma treatment time was ascribed to the change in structural disorder on MWCNT surfaces. Scanning electron microscopic study showed that some defects can be induced in MWCNTs during plasma treatment. Results of thermogravimetric analysis indicated that atmospheric pressure OH plasma is as effective as traditional wet methods for purifying MWCNTs.
- Lee, J.S., Chandrashekar, A., Park, B. M., Overzet, L. J., and Lee, G. S., ” Effects of oxygen plasma on optical and electrical characteristics of multiwall carbon nanotubes grown on a four-probe patterned Fe layer,” J. Vac. Sci. Tehnol. B 23, 1013 (2005). Abstract: We report on the fabrication and electrical characterization of aligned multiwall nanotubes(MWNTs) grown on a four-probe patterned catalyst layer. This structure has been designed to directly measure the electrical property of as-grown MWNTs. The temperature-resistance results show that the aligned MWNTs are semiconducting in directions perpendicular to the tube axis and follow the three-dimentional hopping conduction mechanism. Effects of oxygen plasma on the characteristics of the MWNTs are also investigated. Raman spectroscopy results indicate that oxygen plasma treatments can be used to reduce the carbonaceous material in the film. As the exposure time of oxygen plasma increases, the resistance of the aligned MWNTs increases mainly due to the suppression of current conduction through carbonaceous materials. These results suggest that oxygen plasma treatment is effective in improving the film quality of as-grown MWNTs
- Barankin, M. D., Creyghton, Y., and Schmidt-Ott, A., “Synthesis of nanoparticles in an atmospheric pressure glow discharge,” J. Nanoparticle Res. 8, 511 (2006). Abstract: Nanopowders are produced in a low temperature, non-equilibrium plasma jet (APPJ), which produces a glow discharge at atmospheric pressure, for the first time. Amorphous carbon and iron nanoparticles have been synthesized from Acetylene and Ferrocene/H2, respectively. High generation rates are achieved from the glow discharge at near-ambient temperature (40–80°C), and rise with increasing plasma power and precursor concentration. Fairly narrow particle size distributions are measured with a differential mobility analyzer (DMA) and an aerosol electrometer (AEM), and are centered around 30–35 nm for carbon and 20–25 nm for iron. Particle characteristics analyzed by TEM and EDX reveal amorphous carbon and iron nanoparticles. The Fe particles are highly oxidized on exposure to air. Comparison of the mobility and micrograph diameters reveal that the particles are hardly agglomerated or unagglomerated. This is ascribed to the unipolar charge on particles in the plasma. The generated particle distributions are examined as a function of process parameters.
- Chandrashekar, A., Lee, J. S., Lee, G. S., Goeckner, M .J., and Overzet, L. J., “Gas-phase and sample characterizations of multiwall carbon nanotube growth using an atmospheric pressure plasma,” J. Vac. Sci. Technol. A 24, 1812 (2006). Abstract: Multiwall carbon nanotubes(CNTs) are synthesized using an atmospheric pressure rf plasma jet, with helium feed gas and acetylene gas as the precursor. The nanotubes are grown on a substrate with a thin catalyst (iron)film, with the substrate placed downstream from the plasma on a copper hot plate. In situ Fourier transformed infrared spectroscopy indicates an increase in gas temperature and a decrease in the density of the acetylene molecules at higher plasma powers. The helium metastables in the plasma break the C–H bonds in acetylene, causing molecular dissociation. It is apparent that the resultant formation of unsaturated carbonbonds causes taller and more graphitized CNTfilms to grow, as evident from scanning electron microscopy and Raman analyses of the samples. However, at higher substrate temperatures, taller and better quality films are obtained due to enhanced catalytic activity on the substrate surface.
- Demoisson, F., Raes, M., Terryn, H., Guillot, J., Migeon, H. N., and Reniers, F. A., “Characterization of gold nanoclusters deposited on HOPG by atmospheric plasma treatment,” Surf. Interface Anal. 40, 566 (2008).
- Jongchan Choi, Kyeong-Hwan Lee and Sung Yang.,“Fabrication of PDMS through-holes using the MIMIC method and the surface treatment by atmospheric-pressure CH4/He RF plasma,” J. Micromech. Microeng. 21 097001. Abstract: This note presents a simple fabrication process for patterning micro through-holes in a PDMS layer by a combination of the micromolding in capillaries (MIMIC) method and the surface treatment by atmospheric-pressure CH4/He RF plasma. The fabrication process is confirmed by forming micro through-holes with various shapes including circle, C-shape, open microfluidic channel and hemisphere. All micro through-holes of various shapes in a wide range of diameters and heights are well fabricated by the proposed method. Also, a 3D micromixer containing a PDMS micro through-hole layer formed by the proposed method is built and its performance is tested as another practical demonstration of the proposed fabrication method. Therefore, we believe that the proposed fabrication process will build a PDMS micro through-hole layer in a simple and easy way and will contribute to developing highly efficient multi-layered microfluidic systems, which may require PDMS micro through-hole layers.
- Allcock HR, Steely LB, Kim SH, Kim JH, Kang BK., “Plasma Surface Functionalization of Poly[bis(2,2,2-trifluoroethoxy)phosphazene] Films and Nanofibers,” Langmuir. 2007 Jul 17;23(15):8103-7. Epub 2007 Jun 23. Abstract: Polyphosphazenes are a class of hybrid organic-inorganic macromolecules with high thermo-oxidative stability and good solubility in many solvents. Fluoroalkoxy phosphazene polymers also have high surface hydrophobicity. A method is described to tune this surface property while maintaining the advantageous bulk materials characteristics. The polyphosphazene single-substituent polymer, poly[bis(2,2,2-trifluoroethoxy)phosphazene], with flat film, fiber mat, or bead mat morphology was surface functionalized using an atmospheric plasma treatment with oxygen, nitrogen, methane, or tetrafluoromethane/hydrogen gases. Surface chemistry changes were detected by static water contact angle (WCA) measurements as well as X-ray photon spectroscopy (XPS). It was found that changes in the WCA of as much as 150 degrees occurred, accompanied by shifts in the ratio of elements on the polymer surface as detected by XPS. Overall this plasma technique provides a convenient method for the generation of specific surface characteristics while maintaining the hydrophobicity of the bulk material.
Contact us to receive a complimentary copy of the technical articles utilizing atmospheric plasma above. Please reference the authors and publication number in your email request (copy and paste into your email response).