| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5360686 | Applied Surface Science | 2013 | 8 Pages |
Kapton® [poly (4,4â²-oxy diphenylene pyromellitimide)] polyimides have widespread usage in semiconductor devices, solar arrays, protective coatings and space applications, due to their excellent chemical and physical properties. In addition to their inherent properties, imparting superhydrophobicity on these surfaces will be an added advantage. Present work describes the usage of Ar + O2 plasma treatment for the preparation of superhydrophobic Kapton® surfaces. Immediately after the plasma treatment, the surfaces showed superhydrophilicity as a result of high energy dangling bonds and polar group concentration. But the samples kept in low vacuum for 48 h exhibited superhydrophobicity with high water contact angles (>150°). It is found that the post plasma treatment process, called ageing, especially in low vacuum plays an important role in delivering superhydrophobic property to Kapton®. Field emission scanning electron microscopy and atomic force microscopy were used to probe the physical changes in the surface of the Kapton®. The surfaces showed formation of nano-feathers and nano-tussock microstructures with variation in surface roughness against plasma treatment time. A thorough chemical investigation was performed using Fourier transform infrared spectroscopy and micro-Raman spectroscopy, which revealed changes in the surface of the Ar + O2 plasma treated Kapton®. Surface chemical species of Kapton® were confirmed again by X-ray photoelectron spectroscopy spectra for untreated surfaces whereas Ar + O2 plasma treated samples showed the de-bonding and re-organization of structural elements. Creation of surface roughness plays a dominant role in the contribution of superhydrophobicity to Kapton® apart from the surface modifications due to Ar + O2 plasma treatment and ageing in low vacuum.
⺠Superhydrophobicity attained on Kapton® surfaces after Ar + O2 plasma treatment. ⺠Transition from nano-feathers to nano-tussock morphology was observed as treatment time was increased. ⺠Contact angle of 157ο was achieved by 1 h Ar + O2 plasma treatment and subsequent 48 h low vacuum ageing. ⺠AFM, FESEM, FTIR, XPS and micro-Raman characterizations of Kapton® were performed to probe the surface modifications. ⺠Changes in wetting characteristics were also studied as a result of ageing in various atmospheric environments.
