What is plasma technology and what are its applications?
Plasma technology is commonly used in many industries, including automotive, microelectronics, packaging, and medical devices.
Along with solid, liquid and gas, plasma is a state of matter. Changes of state occur by either adding or removing energy from a substance. For example, if enough heat energy is added to water, it will turn into steam.
If enough energy is added to the gas, the gas molecules ionize and carry a net positive charge. Sufficient ionization affects the electrical properties of the system to the point that it becomes a plasma.
Plasma consists of positive ions, negative electrons, neutral molecules, UV radiation, and excited molecules that can have enormous amounts of internal energy. In the plasma treatment process, any or all of these components may interact with the surface. By choosing the gas mixture, amount of energy, atmospheric pressure and other factors, the effects of the plasma can be adjusted as needed.
Plasma treatment is often performed in a vacuum chamber. After the air is pumped out of the chamber, gas flows in and an electric field is applied to produce plasma. Plasma treatment is usually performed at relatively low temperatures, which allows heat-sensitive materials to be treated.
Plasma treatment is also carried out using so-called atmospheric “jet” plasma. These plasmas operate at ambient atmospheric pressure and are ideal for localized applications in the in-line manufacturing process, possibly using automation.
Plasma treatment is most often used for cleaning, increasing the adhesion of surfaces and producing thin coatings.
Cleaning
Plasma cleaning is able to eliminate oils and grease down to the nanoscale. It can also reduce various contamination risks much more effectively than conventional cleaning processes. Plasma cleaning produces a stain-free surface, suitable for bonding or post-processing, without producing harmful waste.
The ultraviolet light produced in the plasma is very effective in breaking the organic bonds of common surface contaminants, including those in oils and greases. The energetic forms of oxygen in the plasma also carry out cleaning actions, reacting with contaminants to produce mainly water and carbon dioxide.
The plasma process for cleaning easily oxidizable materials such as silver uses inert gases such as argon or helium. In this cleaning process, plasma-activated ions blast organic contaminants, breaking them down so they can be vaporized and removed from the chamber.
Surface activation
Many polymers are inert and do not easily bond with other materials such as paints and adhesives. By attaching polar molecular groups to it, plasma surface activation can increase the adhesion of the polymer material surface.
Plasma surface activation can make polymers much more susceptible to coatings and binders. Oxygen is commonly used in this process; however, many plasma activations can be performed with ambient air. Once activated, materials remain in their altered state for a period of time ranging from a few minutes to many months, depending on the type of material.
Coating
The plasma coating process creates a nanometre polymer layer on the surface of the object. The process only takes a few minutes to create a coating less than 1/100th the width of a human hair. These coatings are typically clear, odourless, and otherwise undetectable.
Plasma coatings are currently a hot topic in many scientific fields because of their enormous potential in a wide range of applications.
Potential future uses
Many predict that plasma will be used in new ways in the not-too-distant future.
One possible use is the destruction of toxic waste. A plasma capable of absorbing enough energy to change the atomic structures of substances could possibly be used to completely eradicate highly harmful toxic substances.
Plasma is already used as a very precise scalpel for medical operations. Hot plasma could also be used medically to cauterize wounds, drill cavities, and disinfect.
Ground-breaking particle scientists are already working with plasma to unlock the secrets of the universe. This research could unlock the secrets of existence, but it could also lead to more practical applications of plasma.
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