Statistical analysis on morphology development of some semialicyclic polyimides using atomic force microscopy

Abstract

The morphological features and surface texture parameters of some polyimide films prepared from a flexible and alicyclic dianhydride, in combination with five aromatic diamines, were evaluated by atomic force microscopy (AFM) in order to determine their applicability in electronics. By means of the surface roughness, shape of the surface height distribution, and angular and radial texture, a precise description of the actual surface topographies at the interface with other materials was made. The polyimide structures led to the development of different surface morphologies (from granular to porous and from bumpy to spiky). The relief diversity was described by the entropy of morphology, which had a similar trend with the root mean square roughness, which presents low values, i.e. 0.5-1.8 nm. Three-dimensional AFM images and the corresponding angular spectra, together with texture aspect ratio and texture direction index (close to 1), indicate that no predominant orientation exists on the investigated surfaces. The redundancy in the morphology was associated with the concept of fractals, the maximum redundancy being achieved for the polyimide with the most complex polymer chain conformation. These results provide useful insights in selecting the polyimide structure, which has the optimal morphology, roughness, orientation, bearing properties, or self-similarity for microelectronic applications such as: substrate for display backplanes, planar technology, microelectronic packaging, etc.

Nanoscopic Investigation of Magnetic Thin Films by Means of Magnetic Force Microscopy Technique

“…If we expect that domain structure will have very complex shape, it can be useful to describe it that way [25]. Figure 7 presents the normalized S dfn parameter based on fractal dimension, related to the thickness of the films.…”

Semi-Alicyclic Polyimides: Insights into Optical Properties and Morphology Patterning Approaches for Advanced Technologies

“…Moreover, the Epiclon-based PIs have the Str parameter higher than 0.3, revealing the isotropic character of the morphology (the surface has the same characteristics in every direction). AFM studies reveal that the enhancement of roughness is generated by the structural peculiarity of these polyimides which contain bulky, alicyclic dianhydride moieties and aromatic diamine residues with different flexibility [57]. The functional and spatial properties obtained for the discussed PI films indicate that these materials present good adhesion with circuit inorganic components, being suited as interlevel dielectric layers.…”

The enrichment of surface passive film on stainless steel during biofilm development in coastal seawater

“…The topographical and three-dimensional features of the surfaces were captured by a computer. As roughness parameters are generally affected by scan size, choosing a size that offers the best illustration of surface features is important for statistical evaluation of the parameters (Stoica et al 2013). Therefore, scan sizes ranging from 5 μm × 5 μm to 100 μm × 100 μm were analysed initially.…”

“…The mean percentage cover and roughness profiles were calculated from triplicate images of biofilms for each test condition. For roughness profiles of surface passive films, images from several 10 μm × 10 μm areas were firstly collected at different sample locations and the homogeneity of the film surface ascertained (Stoica et al 2013). The mean profile parameters for either biofilm or passive film were obtained by positioning the cross hair across 20 random locations each on triplicate pixels (n = 60).…”