Feasibility study of pyromellitic diimide acceptor for electrochromic applications

• Main Author: Lim, Jovan Jun Long
• Other Authors: Lu Xuehong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Ecomaterials; Engineering::Materials::Material testing and characterization
• Online Access: https://hdl.handle.net/10356/166419
• Institution: Nanyang Technological University

Polymeric electrochromic (EC) materials are attractive due to their lower cost, vibrant colours, and solution processibility. Potential applications include smart windows, flexible displays, and thermal camouflage. Donor-acceptor (D-A) polymers further expand the possibilities by enabling extensive structural modification to fine-tune polymer properties. In this work, Pyromellitic Diimide (PMDI) was studied as a potential acceptor species in alternating D-A polymers. Seven novel polymers were synthesised via Stille or Sonogashira cross-coupling polymerisation at the 3,6- position. Alkylation at the N,N' - positions was performed to aid in solvent solubility. Subsequent characterisation revealed varying structural, thermal, optical, and electrochemical properties. The polymers were incorporated into EC devices where spectroelectrochemistry analyses were conducted to determine electrochromic activity. Shortlisted polymers were further subjected to cyclic stability testing. The results demonstrated the possibilities afforded by D-A polymers. Further donors and acceptors pairing can be explored to potentially yield high-performing and stable EC polymers.