Plasma is the fourth state of matter: a partially ionized gas in which free electrons, ions, radicals, and excited neutral species coexist. When a process gas (air, oxygen, nitrogen, argon) is subjected to an intense electric field, its molecules become ionized, generating high-energy, chemically reactive species. Directed onto the surface of a material, these species modify its outermost molecular layers without altering its bulk properties. The effect is threefold: micro-cleaning (removal of organic contaminants, oils, and residues), surface activation (introduction of polar functional groups that increase surface energy and wettability), and etching (micro-erosion that increases anchoring roughness). This results in a drastic reduction in the contact angle and a significant increase in surface tension, conditions essential for reliable adhesion. Applications range from structural bonding to painting, from printing to sealing and coating, on polymers, composites (CFRP/GFRP), metals, glass, and ceramics, in the automotive, electronics, semiconductor, medical, and construction sectors. It is a dry process, free of toxic solvents, eco-friendly, and easily integrated into automated production lines.