Superhydrophobic polyimide via ultraviolet photooxidation: the evolution of surface morphology and hydrophobicity under different ultraviolet intensities

摘要: Ultraviolet (UV) photooxidation has recently been developed to fabricate superhydrophobic polyimide (PI) films in combination with fluoroalkylsilane modification. However, it remains unclear whether the surface morphology and hydrophobicity are sensitive technical parameters such as UV intensity radiation environment. Herein, we focus on effects of PI structure wettability gain comprehensive understanding more effective control this technology. Scanning electron microscopy (SEM) atomic force (AFM) results showed that governed evolutionary pattern morphology: lower (5mW/cm2) facilitated in-plane expansion dendritic protrusions while stronger (10 15mW/cm2) encouraged localized growth a piling-up manner. Surface roughness maximized at 10mW/cm2, consequence slowed horizontal preferred vertical when increased. Based these results, mechanism micro/nanostructures distinct ways exposed different intensities was proposed. Though superhydrophobicity (water contact angle larger than 150°) can be achieved not less higher decreased effectiveness. Therefore, under 10mW/cm2 for 72 h is recommended films.