Substitution and isomeric effects of triarylamine polyamides for electrochromic supercapacitors and heat-shielding applications

Abstract

The development of dual-functional electroactive polymers remains a pivotal and imperative strategy for advancing energy and optical modulation devices. Herein, we report a series of scalable yet straightforward triarylamine-based polyamides featuring substitutional isomerism and backbone engineering to simultaneously enable electrochromic supercapacitors (ECS) and heat-shielding (HS) applications. By integrating ortho- and meta-substituted methyl groups with phenyl ether or cyclohexyl (CH) linkages, we achieve tunable porosity, redox behavior, and intervalence charge transfer (IVCT) responses. Notably, o-TPB-CH exhibits well-separated two-stage oxidation, a high optical contrast (ΔT = 86.7%) with short coloration time (t_c = 4.5 s), and a specific capacitance of 122.2 F g⁻¹ at 1 A g⁻¹, attributed to synergistic effects of ortho-substitution and backbone twisting. The ECS device offers a visible charge-storage state transition from colorless (neutral) to reddish-brown (oxidized), benefiting practical smart-window readability. In heat shielding, o-TPB-CH effectively attenuates 93.3 W m⁻² of near-infrared (NIR) irradiance and gratifyingly reduces thermal gain by 61.8%, retaining 84.9% of its performance after 4 hours. This work underscores the impact of isomeric substitution on electro-optical performance and offers a viable design route for up-and-coming multifunctional polymer platforms.