Amongst these are mechanical or chemical treatments as well as exposure to flames, photons, ion beams and other types of radiation. Non-thermal plasmas are therefore applied for the treatment of polymers, and their use for controlling polymer wettability is the focus of this chapter.Ī number of surface treatments have been applied to modify polymer surfaces in order to enhance properties such as adhesion, wettability and printability. Due to the low density of the gas, collisions with the other species are relatively rare and thermal equilibrium is not reached: the bulk temperature of the gas is comparable to room temperature. For these plasmas, electrons acquire higher energies than heavy particles (ions and molecules)-their energies ranging from 0.1 eV to some electron volts. Non-thermal plasmas, which are often referred to as ‘cold’ plasmas or non-equilibrium plasmas are produced near room temperature or a little above this temperature. Typical examples of thermal plasma sources include plasma torches, plasma spray and arc jets. They heat the entire gas stream during operation.

Thermal plasmas are associated with joule heating and thermal ionisation, which enables the delivery of high power at high operating pressures. Plasmas can be divided into either thermal or non-thermal, the thermal plasmas being characterised by high levels of ionisation. Plasmas are ionised gases, which consist of positive and negative ions, atoms and electrons, as well as neutral species. This gave rise to the use of the word plasma in physics.

In 1928 the American scientist Irving Langmuir proposed that electrons, ions and neutral species in an ionized gas are similar in arrangement to the corpuscular material in blood. In the mid-nineteenth century, the Czech physiologist Jan Evangelista Purkinje introduced the use of the Greek word plasma (meaning to be formed or moulded), to refer to the remains of corpuscular material in blood.

Hdpe surface energy