Small-Angle X-Ray Scattering Study on Nanostructures of Polyimide Films

Abstract

Inorganic nanohybrid polyimide (PI) is widely applied in electrical and electronic devices for its outstanding insulating properties. Samples 100CR and 100NH are made in Dupont. Among them, 100NH is a kind of pure PI films; however, 100CR is a kind of inorganic nanohybrid PI films with excellent corona-resistance. The nanostructure of PI films is investigated with small-angle x-ray scattering technique and transmission electron microscopy (TEM). The normalized volume fractions of the scatterers in the specimens are obtained with a tangent-by-tangent data analysis for the small-angle x-ray scattering data. The multi-hierarchical scatterers of 100NH can be divided into two dominant components, i.e., the sharp component and the wide component. The sharp component is corresponding to the contribution of PI molecular chains, and the wide component includes the aggregates formed by PI molecular chains and the film has nested dual-fractal characteristics, nevertheless the 100CR film possesses three types of scale scattering made up of inorganic nanoparticles, molecular chains and aggregates. The present films have multi-fractal structures. The distribution and structure of scattering body of two kinds of PI films are analyzed. The results of SAXS agree well with those of TEM methods.

Review about the Application of Fractal Theory in the Research of Packaging Materials

“…In the prepared colloidal suspension, the fractal aggregates with size of about 31 nm were observed, as shown in Figure 7. In order to understand the growth mechanism of nano agglomerates and reveal the correlation between microstructure and macroscopic properties, Liu et al [66] tested and analyzed the multifractal structures of pure polyimide (PI) film and inorganic nano hybrid PI film, and studied the spatial distribution and mass uniformity of the scatterers. The materials prepared by self-assembly technology have fractal characteristics.…”

“…In the process of preparing layer-by-layer self-assembled antibacterial films of hyaluronic acid (HA) and chitosan (CHI) biopolymers at two pH values (5 and 3), the fractal dimension of the pH 5 series was about 2.2, and the irregularity of the initial random adsorption process was the least. When the pH value was reduced to 3, the fractal dimension increased to 2.5, indicating that the random adsorption process was in the transition of diffusion limited aggregation [ 66 ]. In the electrospinning process, the length of the electrospinning needle is controlled to realize the structural control of materials at the molecular scale, which shows that the hierarchical structure of macromolecules in the self-assembly process has fractal characteristics [ 67 ].…”

Nanostructured oxyhydroxide niobium (NbO2OH) as UV radiation protector for polypropylene

“…6, will show linear relation with a negative or a positive slope representing a negative or positive deviation from Porod's law. 26 The presence of either thermal electronic movement or compositional heterogeneity within scattering elements causes positive deviations, 19 and the presence of the diffuse phase boundary results in a negative slope of Porod's plot. 14 The minor positive and the negative deviation coexist in NbO 2 OH, Fig.…”

“…Because the scattering from the different phases has been separated, further analysis of data are possible. 26,27 The Table 1 presents the results. At Table 1, the equidistant peaks indicate the presence of lamellar structures in the samples (for lamellar morphology, the q value of the Bragg's show relationships 1 : 2 : 3 : 4 : 5).…”

Research of Trap and Electron Density Distributions in the Interface of Polyimide/Al 2 O 3 Nanocomposite Films Based on IDC and SAXS

“…[8] Liu et al also proposed the multi-fractal nanostructures of polyimide films based on SAXS tests. [9] The traps in the interface of polymers can influence the distribution and transport of space charges in nanodielectrics. The distribution of electron density in the interface of polymers is closely related to space charge distribution, which can reflect the characteristics of trap distribution and carrier transport.…”