Comparative Study on Three-Dimensional Morphological Changes of Polyimide Films Exposed to Oxygen Plasma and Pulsed Uv-Laser (original) (raw)
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High Energy Chemistry, 2000
The influence of alternating radiofrequency-plasma and heat treatment on the structure and bulk properties of polyimide films and coatings with a thickness of 3.5 µ m was studied. It was shown that plasma treatment leads to the enhancement of the specific surface energy due to the polar component and to an increase in the diffusion coefficient and in the amount of sorbed water. The subsequent thermal treatment leads to the recovery of the polyimide surface and bulk properties to almost their initial magnitudes. It was assumed that these effects are caused by a change in the structure of thin films and coatings and by the buildup of negatively charged particles at the surface and in mesopores of the polymer upon RF plasma treatment and due to annealing upon thermal treatment.
Nanostructured Polyimide Films by UV Excimer Laser Irradiation
SCIENCE AND …, 2010
Abstract. Here we present a study of the polyimide films nanostructuring by KrF laser beam irradiation and the investigation of the mechanism of cone-like structure formation at two laser fluences, 57 and 240 mJ/cm2. These films were prepared from fluorinated poly ( ...
Polyimide films tailored by UV irradiation: Surface evaluation and structure-properties relationship
Polymer Degradation and Stability, 2020
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Journal of Applied Physics, 1994
Polyimide films were treated in air with an argon-fluorine ultraviolet excimer laser (A= 193 nm). X-ray photoelectron spectroscopy analysis was performed on the modified surfaces after laser exposure at various fluences around the expected threshold fluence Fth . From the present data the photochemical process (photoablation) leads to produce a carbon-rich surface by ejecting mainly oxides of carbon and nitrogen compounds above a particular fluence F,.
Nanotopology of Polyimide Films Obliquely Treated by Plasma Beam and Liquid Crystal Alignment
Molecular Crystals and Liquid Crystals
The correlation between nanorelief of polyimide films obliquely treated by the beam of accelerated Ar plasma and liquid crystal (LC) alignment on these films is investigated. It is shown that the plasma beam treatment results in the change of films' roughness in a nanometer scale. In this case, the values of roughness in the directions parallel and perpendicular to the plasma beam projection on the films are different and dependent on the exposure dose. Clear correlation between the anisotropy of surface roughness and the direction of LC alignment is observed. This implies that topology is important, possibly decisive, factor of planar LC alignment on the surfaces obliquely treated by plasma beam.
2013
An aromatic photosensitive polyimide is prepared from 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 4,4'-diaminodiphenyl methane and its structuring ability upon UV-laser exposure is investigated. Surface modification is performed at two laser fluences, i.e. 89 and 244 mJ/cm2, and different number of pulses. The changes of the surface morphology, induced by the employed patterning technique, are examined. According to atomic force microscopy data cone-like structures are formed and their appearance mechanism is analyzed taking into account the laser irradiation conditions. Surface wettability tests reveal an intensification of hydrophobic character, which may be ascribed to the formation of a thin carbon-enriched layer at the polyimide surface.
As an attractive dielectric material, polyimide has been widely used in the field of electronics, aerospace, and automobiles due to its useful mechanical properties and good chemical resistance. UV irradiation was considered to be the main factor related to the damage and failure of polyimide. Here the effects of UV irradiation on the surface morphology and microscale mechanical properties of polyimide films are characterized by atomic force microscopy (AFM). The surface roughness of the UV-irradiated samples developed and the mechanical properties degraded with the radiation dose increased. For comparison, uniaxial tensile test was performed to obtain the macroscale Young's modulus of polyimide film. The UV-irradiated damaging depth was simulated with finite element method (FEM).
Applied Surface Science, 2007
Although UV laser is proved to be an effective tool to prepare microstructure on polymer surface, laser ablation accompanied by the formation of laser induced periodic surface structure (LIPSS) limits its application in many fields. The purpose of this report is to investigate the effect of preirradiation in advance, using a low-fluence laser, on the LIPSS formation. The properties of pre-irradiated PI films were characterized by X-ray photoelectron spectroscopy (XPS), surface tension based on the contact angle measurements and UV-vis spectra. It was found that pre-irradiation at low fluence led to the changes in surface property such as chemical components though no LIPSS was formed. As a result, threshold of LIPSS formation on such pre-irradiated PI film decreased and fine LIPSS with deeper amplitude was obtained. #
Surface Modification of Polyimide (PI) Films using Ar and N 2 Hot Cathode Plasma Treatment
NA, 2015
The effects of N 2 and Ar plasma treatment on the surface of polyimide (PI) films were investigated. FT-IR analysis showed the appearance and intensification of the N-H, O-H, C=O, and CC peaks. The use of N 2 and ArN 2-plasma treatment was very effective in increasing the hydrophilicity of the PI films. Decreased contact angles using deionized water may be attributed to the nitrogen functionalization of the PI surface. The treatment which introduced the highest hydrophilicity was found to be Ar-N 2 which is attributed to the lowest values for contact angles, roughness and kurtosis. Argon plasma exposure caused hydrophobicity of the PI film which may be attributed to the increased roughness, kurtosis and contact angles. Pure-N 2 treated samples also exhibit satisfactory hydrophilic properties due to intermediate topography and wettability properties.
Surface characterization of pulsed UV-laser modified polyamide films
Thin Solid Films, 1997
Thin film samples of Kapton HF polyamide have been modified by UV-radiation using a pulsed excimer laser with per pulse fluences ranging from 29-50 mJ/cm 2. The resulting samples have been characterized using Scanning Tunneling Microscopy, Atomic Force Microscopy, FTIR ATR spectroscopy and Surface Enhanced Raman Spectroscopy. Topographical results indicate that, as per pulse fluence increases, surface melting, vaporization and eventually surface ablation occur. Raman results indicate the formation of graphitic carbon at the surface of the film. For highly modified samples, the graphitic carbon exists in regions which exhibit localized structure on the nanometer scale. For these samples, only graphitic carbon is present at the surface of the film. For samples which involve a lesser degree of modification, both polyamide and carbon are present at the surface of the film. FTIR ATR results are consistent with a loss of crystallinity and an introduction of new conformadonal states in the bulk of the polyamide film due to subsurface heating. © 1997 Elsevier Science S.A.