Evaluation of Polyimide Coatings Integrity by Positron Annihilation Lifetime Spectroscopy and Electrochemical Impedance Spectroscopy

Abstract

the LPDO nitrides. This result is very different to the conventional APDO nitrides, in which only the N/O structure is obtained. The distinct O/N/O structure is conjectured to result in the good electrical properties for the LPDO nitrides. Finally, the oxidation mechanisms of the LPDO, APDO, and APWO of nitride films are also depicted.

Palladium nanoparticles encapsulated in polyimide nanofibers: An efficient and recyclable catalyst for coupling reaction

“…Table 4 shows that the thermal condensation process has reduced the size of free volume holes and raised its concentration, which could be attributed to the formation of polyimide. [38] After reuse, the concentration of free volume holes was ascended, which indicated the degradation of polyimide in the nanofibers. Thus, it can be concluded that the increment of free F I G U R E 1 0 (a) X-ray diffraction (XRD) pattern and (b) X-ray photoelectron spectroscopy (XPS) of the recovered palladiumencapsulated polyimide (Pd@PI) catalyst after recycling for 10 times (Heck reaction) volume holes in Pd@PI catalyst might be the main reason responsible for the leaching of palladium species, which in turn reduced its catalytic activity.…”

Structure and Transport in Coatings from Multiscale Computed Tomography of Coatings—New Perspectives for Eelectrochemical Impedance Spectroscopy Modeling?

“…The larger the inhibitor molecule then the less likely it will be able to diffuse through the polymer matrix. At the atomic level the polymer matrix has porosity between the polymer chains called the molecular pore volume which can be probed directly using positron techniques [21][22][23].…”

“…Local variation in density of the polymer itself such as with the LDE components mentioned above, v. Mixed pore networks particularly those that are not connected to the external surface but reach the metal/coating interface or vice versa Summarising with respect toFigure 5, the types of pore networks mentioned in the literature have a range of scales from that of molecular pore volume (case (i)) to microporous defects (case (ii)). For example, penetrative pathways through the polymer itself may range in scale from micropores 41 or domains with different polymer density (LDE) [1,2] down to pathways through the intramolecular volume [22,35]. There is also likely to be a strong dependence on the chemistry of the polymer and the cross linking agent [22,23].…”

“…For example, penetrative pathways through the polymer itself may range in scale from micropores 41 or domains with different polymer density (LDE) [1,2] down to pathways through the intramolecular volume [22,35]. There is also likely to be a strong dependence on the chemistry of the polymer and the cross linking agent [22,23].…”