Electrochromic Linear and Star Branched Poly(3,4-ethylenedioxythiophene−didodecyloxybenzene) Polymers

• Published in: Macromolecules Vol. 33; no. 6; pp. 2083 - 2091
• Main Authors: Wang, Fei, Wilson, Michael S, Rauh, R. David, Schottland, Philippe, Thompson, Barry C, Reynolds, John R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21.03.2000
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Linear copolymer; Phenylene derivative copolymer; Solution polycondensation; Electrochromism; Experimental study; Thermal stability; Thermochromism; Star copolymer; Electrochemical properties; Grignard reaction; Conjugated copolymer; Optical properties; Preparation; Switching time; Time curve; Alternating copolymer; Thiophene derivative copolymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma9918506

New linear and star structured poly(3,4-ethylenedioxythiophene−didodecyloxybenzenes) (PEBs) have been prepared which exhibit thermochromism and multicolor electrochromism as they are able to produce the three basic colors in the RGB system:  red, green, and blue. The star polymer features a conjugated hyperbranched poly(triphenylamine) core with PEB arms ca. 8−10 repeat units (16−20 rings) in length. Red in solution, the optical spectra of both polymers exhibit a maximum absorption at 455 nm in the neutral state. Linear and star PEB are thermally stable up to 300 °C as demonstrated by TGA. The presence of an EDOT-phenylene repeat in the conjugated backbone results in a relatively low half-wave potential of +0.20 V vs Fc/Fc+, which is lower than regioregular poly(3-hexylthiophene) by 0.4 V and only slightly higher than PEDOT. As a result, star PEB is the first representative of a new class of star-shaped polymers where it is possible to address the electroactive arms independently from the conjugated core. The redox switching properties of these star PEBs are quite stable with a 90% retention of electroactivity after 4500 double potential switches. These properties are of particular importance for electrochemically based display applications where highly stable processable electrochromic polymers are needed.