Effect of oxygen plasma treatment and gold sputtering on morphological and local mechanical properties of copolyimide/gold micropatterned structures

Abstract

Atomic force microscopy (AFM) was used to analyze rectangular 3-dimensional patterned microstructures with different functionalities induced on copolyimide containing alicyclic sequences film surfaces by means of oxygen plasma treatment. The plasma power was ranged to be big enough to accelerate the plasma species towards the copolyimide surface, and the exposure time was not very small to generate a roughness that still can be monitored by AFM. To create the rectangular pattern, transmission electron microscopy grid masks were placed on the samples before treatment. Plasma-induced micropatterning with alternating hydrophilic and hydrophobic surface chemistries was evaluated by measuring the adhesion forces between the gold-covered AFM tip and the copolyimide surfaces. To fabricate 3-dimensional metallic microstructures arranged in well-defined areas, thin metal layers were sputtered on these pretreated copolyimide films. The AFM morphological aspects of the obtained metallic structures were correlated with the surface modifications induced by plasma treatment conditions. Functional indexes and functional volume parameters were also calculate to characterize the functional behavior of the surface, such as wear, lubrication, and contact. The AFM data were compared with those obtained using the small-angle X-ray scattering measurements.