**1. Introduction**

Polyimides are advanced polymeric materials that are well known for their excellent thermal, electrical, mechanical, and chemical properties [1]. Polyimides are particularly interesting for microelectronics as well as for high voltage electrical engineering industry, thanks to their high thermal stability, high glass transition temperature, low dielectric constant, and overall very good electrical insulation properties (high breakdown field, low dielectric loss factor, and low conductivity). Polyimides present also an ease of processability making them patternable for many types of integrated electronic devices [2]. In the last 20 years, with the emergence of a wide range of novel electronic applications, polyimides have regained an increasing interest from both fundamental researches and applicative research and development sides, as shown in **Figure 1** where the publication map across the scientific fields and the total number of publications in Electrical Engineering and Electronics edited journals between 1975 and 2019 are presented.

Thus, one can observe that two publication thresholds occurred in 1999 and 2011 leading now to an annual dissemination activity on polyimides close to 4,000 publications for only the Electrical Engineering and Electronics domains. This clearly proves the large interest that these polymeric materials arouse and this trend should still progress over the next coming years.

Polyimides are present in different ways (from substrates to thin coatings) and for different purposes (purely mechanical one to advanced electrical insulation) in
