A2 + B4-type hyperbranched polyamides with multiple redox sites designed for self-adaptive electrochromic application

A 2 +B 4 -type hyperbranched PAs with multi-electroactive nitrogen centers feature multicolor switching and significant optical contrast, promising applications in energy-saving windows and self-adaptive camouflage. • A 2 + B 4 -type HPAs containing multiple redox centers and methyl piperazine groups are synthesized • HPAs exhibit excellent EC properties such as rich color variation, low E onset , long term cyclic stability and remarkable optical contrast • ECDs based on MP3TPA-CA with good cycling stability have promising applications in smart window and self-adaptive camouflage Electrochromic (EC) materials have great potential in display technology, smart windows, and camouflage fields. However, there are some obstacles impede the advance of application, such as color, stability and processibility. Herein, we have developed a high-performance EC hyperbranched polymers (HPs) based on a novel polytriphenylamine monomer. A series of novel A 2 + B 4 -type hyperbranched polyamides (HPAs) containing multi-electroactive nitrogen centers were synthesized using a facile one-pot method which exhibit good processability, as well as EC properties, including significantly reduced onset voltage, ultra-long stability, high optical contrast (ΔT), and excellent coloring efficiency (CE). Among them, MP3TPA-CA exhibits a high ΔT of 77 %, and a high CE of 368 cm 2 /C at 1166 nm. And MP3TPA-SA exhibits excellent switching stability, maintaining 80 % ΔT after the 3720th switching cycle. Furthermore, MP3TPA-CA -based EC device model is demonstrated in smart window and self-adaptive camouflage. The HP materials will pave the way for the exploitation high-performance EC materials.