Atmospheric plasma enhances interlayer adhesion in high-performance 3D-printed polymers by modifying surface energy, morphology and chemical composition

3D-printed components fabricated by processing high-performance polymers through Material Extrusion continue to face challenges with poor interlayer adhesion, resulting in reduced mechanical performance. In this study, the authors propose an innovative thermal-free method to enhance interlayer adhesion by integrating atmospheric plasma treatment directly into commercial 3D printers. Various features of plasma-treated surfaces were investigated, and optimal conditions for working distance and treatment time were experimentally determined. The mechanisms underlying the plasma-polymer interaction were characterized on multiple levels: i) surface energy, ii) surface morphology, and iii) surface chemical composition. The primary benefits observed for treated polycarbonate (PC) and polyetheretherketone (PEEK) included a significant increase in wettability (exceeding 60%), surface crystallization, and the introduction of new functional groups such as hydroxyl, carboxyl, and carbonyl groups. These key factors collectively resulted in a 30.7% improvement in Interlaminar Shear Strength (ILSS), demonstrating the potential of this approach to significantly enhance the mechanical properties of high-performance 3D-printed components. This study lays the foundation for broader adoption of plasma treatment in the fabrication of structurally demanding and high-performance polymer components.