plasmainitiated

Plasmainitiated refers to processes that are initiated by exposure to plasma, an ionized gas containing electrons, ions, neutral species, radicals, metastables, and photons. In plasmas used for materials processing, these species can drive chemical reactions, create reactive surface sites, or initiate polymerization at temperatures much lower than those required for thermal initiation.

Mechanism: In non-thermal plasmas, high-energy electrons transfer energy to molecules, generating radicals that start chain reactions or crosslinking. Ions may bombard surfaces, causing etching or functionalization. UV photons from excited species can initiate photochemical reactions. The combination enables initiations that are difficult under conventional heating, often with limited thermal load on the substrate.

Types and applications: Plasma-initiated polymerization and coating formation, where monomers are activated by plasma to form thin films. Plasma-initiated grafting attaches functional groups to polymer or biomaterial surfaces to tailor wettability or biocompatibility. Plasma-activated surface modification improves adhesion and wettability of metals, polymers, and ceramics. Plasma-enhanced deposition methods, including plasma-enhanced chemical vapor deposition, rely on plasmainitiation to form films at reduced temperatures. Common plasma sources include dielectric barrier discharge, inductively coupled or capacitively coupled plasmas.

Advantages and limitations: Plasmainitiated processes operate at low bulk temperatures, can be solvent-free, and enable conformal, surface-specific treatments. Limitations include potential surface damage from energetic ion bombardment, limited treatment depth, and the need for controlled environments and equipment.

History and scope: The concept grew from plasma chemistry research in the mid-20th century and has become integral to electronics manufacturing, biomedical device fabrication, coatings, and surface engineering.