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• 634591-75-6 3,3-bis[[(2-ethylhexyl)oxy]methyl]-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin 

Relevant academic research and scientific papers

Tuning the painter's palette: Subtle steric effects on spectra and colour in conjugated electrochromic polymers

A series of vibrantly coloured π-conjugated electrochromic polymers (ECPs) were designed and synthesized with the goal of extracting structure-property relationships from subtle changes in steric strain or relaxation. These are soluble all donor, electron rich, alternating polymers based on repeat units of 3,4-ethylenedioxythiophene (EDOT), 3,4-propylenedioxythiophene (ProDOT), and an acyclic dioxythiophene (AcDOT) in varying combinations to tune steric interactions and the subsequent optical absorption for fine colour control. Two families of polymers were formed where ProDOT2-EDOT, ProDOT-EDOT, and ProDOT2-EDOT2 constitute new shades of blues while AcDOT2-ProDOT, AcDOT-ProDOT, and AcDOT-EDOT yield new hues of magentas with the homopolymers of ProDOT and AcDOT and the copolymer AcDOT2-EDOT2 serving as comparisons. The polymers were synthesized using direct (hetero)arylation polymerization. Examinations of the optoelectronic properties via cyclic voltammetry, spectroelectrochemistry, and colorimetry show that by subtly varying the level of steric relaxation or strain in the form of EDOT or AcDOT content, lower or higher energy absorption transitions are produced respectively. This increase in relaxation or strain allows more short or long wavelength light to transmit, giving new shades of blues or magentas respectively. Since these are all donating polymers, they exhibit changes in contrast no less than 70% at the λmax with the exception of AcDOT-EDOT. The most desirable electrochromic properties were achieved with ProDOT2-EDOT2 and AcDOT2-ProDOT, with band gaps (Eg) and neutral state Lab colour values (-a and +a correspond to green and red and -b and +b correspond to blue and yellow respectively and L represents the lightness) of 1.74 eV, 37, 12, -63 and 2.01 eV, 56, 59, -16 respectively. The highly transmissive oxidized state colour values for ProDOT2-EDOT2 and AcDOT2-ProDOT are 92, -3, -3 and 91, -2, -1 respectively. These structure-property relationships grant a greater ability to tune light absorption across the visible, with colour properties similar to ECPs made through other methods without using donor-acceptor effects. This all donor steric tuning method leads to considerably higher levels of transparency when the polymers are fully oxidized.

Reversible full-color generation with patterned yellow electrochromic polymers

A different light: The yellow electrochromic copolymer, propylenedioxythiophene phenylene P(ProDOT-Ph) is patterned by the micromolding in capillaries (MIMIC) process to fabricate line gratings. Under illumination by white light, colors are generated by diffraction and can be changed by applying an external voltage (see picture). The diffracted color is blue shifted by electrochemical doping, a process that is completely reversible. Copyright

Spray coatable electrochromic dioxythiophene polymers with high coloration efficiencies

Four new disubstituted propylenedioxythiophene polymers have been synthesized by Grignard metathesis on the 1-5 g scale. All polymers were found to be soluble in chloroform, methylene chloride, toluene, and tetrahydrofuran and were fully structurally characterized having GPC determined number-average molecular weights ranging from 33000 to 47000 g mol-1. Dilute polymer solutions in toluene exhibited strong red fluorescence with moderate quantum efficiencies from 0.38 to 0.50. Homogeneous thin films were formed by electropolymerization and spray casting polymer solutions onto ITO coated glass slides at thicknesses of ca. 150 nm. The films were electroactive, switching from a dark blue-purple to a transmissive sky blue upon p-doping, often with subsecond switching times, and high electrochromic contrast luminance changes (% ΔY) of 40-70%. These studies revealed that the branched derivatives, [poly(3,3-bis(2-ethylhexyl)-3,4-dihydro-2H-thieno[3,4-o] [1,4]dioxepine)] and [poly(6,8-dibromo-3,3-bis(2-ethylhexyloxymethyl)-3,4-dihydro-2H-thieno[3,4-b][1, 4]dioxepine)], gave an electrochemical response and associated color change over a much smaller voltage range in comparison to the linear chain substituted derivatives, [poly(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-o][1,4]dioxepine)] and [poly(3,3-bis(octadecyloxymethyl)-3,4-dihydro-2H-thieno[3,4-b] [1,4]dioxepine)]. Composite coloration efficiency values were found up to 1365 cm2/C; this was considerably larger than values obtained from previously studied alkylenedioxythiophene based polymers (～375 cm2/C).