Surface modification of polyimide films towards very low contact angles

• Polyimide films activated in a structure-depending manner by simultaneous mechanisms. • Plasma exposure generated severe modifications in surface parameters. • Small gains in optical transmittance and structure-dependent roughness enhancement. • A 50° downshift in water contact angle values. • An acceleration of fibroblast seeding in the first 24 h of cell culture. Homogeneous plasma treatment was used as a viable approach to modulate the surface characteristics of two polyimide films obtained by high-temperature polycondenzation and conventional casting. Physicochemical transformations of the polymeric materials’ surface were addressed through an interconnected parallel between bulk features, surface chemistry, topography, and wettability before and after exposure to plasma. Rigorous FTIR investigations, further complemented by EDX analysis, were used to qualitatively assess mechanistic insights and plasma-triggered surface chemical modifications by monitoring the main changes in the position and integrated surface area of principal absorption bands. The film-forming conduct and surface specifics of pristine and modified materials were evaluated in terms of mechanical stability, flexibility, morphology, optical transmittance, and roughness fluctuations. The connection between the plasma-induced hydrophilization of the two films and severe changes in polar:dispersive surface components, work of adhesion, and surface energy were thoroughly analyzed. Short- and long-term cell proliferation studies of the pristine and activated films were employed to determine the effect of plasma-induced modifications upon fibroblast growth.