Atmospheric Chemical Plasmas

Atmospheric chemical plasma treatment system for webs... 

Atmospheric chemical plasma treatment systems are typically non-thermal, atmospheric-pressure, glow-discharge plasma systems that generate uniform and homogenous treatments. The level of surface tension and iongevity of treatment are both typically higher than air plasma treatment effects, and similar in treatment effect to flame plasmas. 

While these systems can provide an improvement over air corona, they fall considerably short of the results achievable with atmospheric chemical plasmas. As we will see, atmospheric plasmas create a fourth state of matter which differentiates its surface modification potential beyond what either a corona or chemical corona system can achieve. In turn, the treatment results of an atmospheric plasma system not only outperform corona systems, but they also can offer limitless possibilities. 

Like corona, plasma is the electrical ionization of a gas. An atmospheric chemical plasma (glow) discharge creates a smooth, undifferentiated cloud of ionized gas with no visible electrical filaments. Unlike corona, plasma is created at much lower voltage levels. 

Figure 7.2 Photographic exposure (1/1000 s) of corona and atmospheric chemical plasma discharges between an electrode and ground plane. (Source Enercon Industries Inc.)...

One of the critical surface effects of an atmospheric chemical plasma on a given material is determined by the chemistry of the reactions between the surface and the reactive species present in the plasma. At the low exposure energies typically used for surface treatment, the plasma surface Interactions only change the surface of the material the effects are confined to a region only several molecular layers deep and do not change the bulk properties of the substrate. The resulting surface changes depend on the composition of the surface and the gas used. 

Also similar to vacuum plasma regimes, the ionization of atmospheric chemical plasma process gases is accomplished by applying an energy field using one of three source frequencies regulated by the federal government ... 

The physical nature of an atmospheric chemical plasma varies according to the type of gas, mixture of gases, the input pressure of gases used, the confinement (or lack thereof) of the plasma, and the type of electrical field which maintains the plasma. Putting all of these parameters to work, the degree of ionization of an atmospheric chemical plasma becomes directly relative to the proportion of atoms which have lost or gained electrons within the ionization process, which is in turn driven by the plasma process temperature (typically directly related to applied electrical power) and its control. 

Atmospheric chemical plasma interaction with the surface of a substrate causes several effects, each of which influences the adhesion process. These effects are inclusive of, but not restricted to ... 

Compared with vacuum plasma batch processes, the opportunity to apply atmospheric chemical plasma surface treatments to material surfaces on continuous production lines with similar surface cleaning and adhesion promotion performance is economically attractive. 

Atmospheric chemical plasma station control metrics... 

Atmospheric chemical plasma power generator metrics... 

Atmospheric pressure plasma Physical-chemical procedure for surface pretreatment, in particular of plastics. It is based on the development of an ionized gas atmosphere by high voltage, and leads to the formation of active surfaces. In contrast to the low-pressure plasma, it works at atmospheric pressure. 

In general, QE-AAS, AES, AES, microwave induced plasma (MIP) and ICP-MS are used as detectors rather than the less specific FID, FPD, and ECD. The overriding reason for this is the greater sensitivity and selectivity afforded by the element-specific detectors, without which it would not be possible to determine the chemical species of interest at the low concentrations generally present in biological and environmental samples. The other main detection method that has been used is mass spectrometry in its various configurations, but particularly electrospray ionization (ESI) and atmospheric chemical ionization (APCI), which are used with HPLC and CE separations, and... 

Y. Hong, C. Bang, D. Shin, H. Uhm, Band gap narrowing of Ti02 by nitrogen doping in atmospheric microwave plasma . Chemical Physics Letters, 413, 454-457, (2005). 

Herrmann, H.W., et al. Decontamination of chemical and biological warfare, (CBW) agents using an atmospheric pressme plasma jet (APPJ). Physics of Plasmas 6(5), 2284-2289 (1999)... 

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