Plasma is a state of matter, just like solids, liquids, and gases. In fact, plasma is often called the fourth state of matter. Any ionized gas is a plasma. An ionized gas has electrons, ions and neutral atoms and molecules in various proportions.

One way to generate a plasma is by passing an electric current through a gas. Electrons from the electrical current become part of the gas and cause the gas atoms and molecules to become ionized, or charged. The amount, or degree, of ionization is called the "plasma density".

Generally, high plasma densities are desirable, because electrons impact gas molecules and create the excited-state species used for textile treatment. Having more electrons generally equates to faster treatment time. However, very high plasma densities (greater than 10¹³ electrons cm^-3) can only exist with very high gas temperature. This extremely high level of plasma density is unsuitable for textile treatment, because the plasma's energy will burn almost any material. These plasmas, often called thermal plasmas, are used for incineration.

High Density Without High Temperature
APJeT's proprietary APPJ® technology has the highest possible plasma density (in the range of 1 to 5 x 10¹² electrons cm^-3 ), without the associated high gas temperatures. APJeT's "cold" plasma chemically treats fabric and other substrates without subjecting them to damaging high temperatures. As a result, APJeT's atmospheric-pressure plasma technology can treat materials faster than any other cold plasma-just one key reason why APJeT's plasma technology is inherently superior to conventional atmospheric-pressure or vacuum-based plasmas.

How APJeT Technology Works
Electrons in the gas phase are extremely light and therefore are highly mobile-much more mobile than gas molecules. The negative electrical charge of an electron, coupled with its high mobility, causes electrons to oscillate rapidly in the presence of the fast-changing changing electric field that we apply using our proprietary source technology. Because this electrical energy is coupled primarily to electrons, which have very little mass, the electrons in our plasma can be whipped up to high energy by the applied radio frequency field. Since it is the electrons that do the chemical work, the chemistry proceeds as if the temperature was very high (thousands of degrees), even though the actual gas temperature remains low, virtually unchanged by the process. In this way, we achieve the chemical reactivity that only would be possible at 30,000 degrees C, but without the destructive nature that results from operating at such high temperatures.

For example, we can collide the fast-moving electrons in our plasma with ordinary gas molecules, such as O₂. This splits the oxygen molecule and generates two highly-reactive oxygen atoms from every O₂ molecule:

The atomic oxygen produced this way is chemically-reactive to fabric and other substrates, in contrast to the original oxygen molecule, which is not reactive. However, atomic oxygen can only exist for about 1 millisecond at atmospheric pressure before it is converted to another form or back to an oxygen molecule. To use the atomic oxygen for textile manufacturing, we must ensure that the fiber or fabric reacts with the atomic oxygen in less than 1 millisecond. Our proprietary textile machine design ensures this rapid reaction. As a result, the atomic oxygen becomes permanently bonded, or grafted, onto the fabric, providing a different attribute than untreated fabric. Essentially, plasma treatment converts ordinary fabric into fabric with unique properties.

APJeT Plasma Source Designs
APJeT's proprietary source technology includes:

Downstream Plasma Machines -The plasma produced inside the source is "blown" out and onto the substrate. Downstream units are trademarked e-Rio® , for "electron river".

In-situ Plasma Machines -The substrate is moved into the machine and immersed in the plasma for treatment. In-situ units are trademarked APPR ®, for atmospheric pressure plasma reactor.

Thin-Film Deposition Machines -These sources operate in the downstream mode and produce a selectable, thin-film deposition on a wide variety of substrates.

Downstream Plasma Method:

In-situ Process Method:

Film Deposition Plasma Jet: