Electrosyntheses and characterizations of a new soluble conducting copolymer of 5-cyanoindole and 3,4-ethylenedioxythiophene

Electrochemical copolymerization of 3,4-ethylenedioxythiophene and dithienothiophene: influence of feed ratio on electrical, optical and electrochromic properties

Designing a copolymer is an efficient and alternative method to generate new chemical and physical properties compared to parent homopolymers without complex synthesis and structural modification. We herein report the electrochemical deposition of copolymer using two monomers 3,4-ethylenedioxythiophene (EDOT) and dithieno[3,2-b:2',3'-d]thiophene (DTT). Three different copolymers P[EDOT-co-DTT] were synthesized by using different feed ratios of monomers (EDOT and DTT molar ratios in solution are 2 : 1, 1 : 1 and 1 : 2) in acetonitrile containing 0.1 M tetrabutylammonium perchlorate (TBAClO4) as a supporting electrolyte. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and UV-vis-NIR spectroscopy were employed to characterize the obtained copolymers. Energy dispersive X-ray spectroscopy (EDX) analysis was used to estimate the composition of EDOT and DTT units in copolymers. The electrochemical and morphological properties were analyzed using cyclic voltammetry (CV) and field emission scanning electron microscopy (FESEM). In situ spectroelectrochemistry and electrochromic studies were performed to investigate the optical and switching properties of the resultant copolymers. The homopolymers poly(3,4-ethylenedioxythiophene) (PEDOT) and polydithieno[3,2-b:2',3'-d]thiophene (PDTT) were also prepared using similar electrochemical conditions and made comparisons where applicable. Computational calculations were done to understand the structure and energy levels of these polymers. It was found that these copolymers P[EDOT-co-DTT] show new properties as compared to homopolymers PEDOT and PDTT for organic electronic applications. Interesting to note that the resultant copolymers display the property of tunable electrochromism with improved transmittance and redox color change between the neutral and oxidized states.

The Different Outcomes of Electrochemical Copolymerisation: 3-Hexylthiophene with Indole, Carbazole or Fluorene

Electrochemical polymerisation is reported to be a method for readily producing copolymers of various conjugated molecules. We employed this method for mixtures of indole, carbazole or fluorene with 3-hexylthiophene (HT), in order to obtain their soluble copolymers. Although polymer films were obtained, infrared (IR) and Raman investigations showed that instead of the expected linear copolymers, polyindole and polycarbazole N-substituted with HT, as well as a poly(3-hexylthiophene) (PHT)/polyfluorene blend were produced instead. Boron trifluoride diethyl etherate was also used in an attempt to promote copolymerisation, but the produced deposits were found to be highly degraded.

Combined use of breath figures process and microphase separation of PS-b-P4VP to produce stable porous nanomaterials

Among various templating strategies available for the preparation of porous polymer films, Breath Figures (BFs) as a fast, low-cost and versatile method has aroused extensive interest.

Applications of Tris(4-(thiophen-2-yl)phenyl)amine- and Dithienylpyrrole-based Conjugated Copolymers in High-Contrast Electrochromic Devices

Tris(4-(thiophen-2-yl)phenyl)amine- and dithienylpyrrole-based copolymers (P(TTPA-co-DIT) and P(TTPA-co-BDTA)) were electropolymerized on ITO electrode by applying constant potentials of 1.0, 1.1, and 1.2 V. Spectroelectrochemical investigations revealed that P(TTPA-co-DIT) film displayed more color changes than P(TTPA-co-BDTA) film. The P(TTPA-co-DIT) film is yellow in the neutral state, yellowish-green and green in the intermediate state, and blue (1.2 V) in highly oxidized state. The ∆T_max of the P(TTPA-co-DIT) and P(TTPA-co-BDTA) films were measured as 60.3% at 1042 nm and 47.1% at 1096 nm, respectively, and the maximum coloration efficiency (η) of P(TTPA-co-DIT) and P(TTPA-co-BDTA) films were calculated to be 181.9 cm²·C⁻¹ at 1042 nm and 217.8 cm²·C⁻¹ at 1096 nm, respectively, in an ionic liquid solution. Dual type electrochromic devices (ECDs) consisting of P(TTPA-co-DIT) (or P(TTPA-co-BDTA)) anodic copolymer, ionic liquid-based electrolyte, and poly(3,4-(2,2-diethylpropylenedioxy)thiophene) (PProDOT-Et₂) cathodic polymer were constructed. P(TTPA-co-BDTA)/PProDOT-Et₂ ECD showed high ΔT_max (48.1%) and high coloration efficiency (649.4 cm²·C⁻¹) at 588 nm. Moreover, P(TTPA-co-DIT)/PProDOT-Et₂ and P(TTPA-co-BDTA)/PProDOT-Et₂ ECDs displayed satisfactory optical memory and long term switching stability.

Electrochemical synthesis, optical, electrochemical and electrochromic characterizations of indene and 1,2,5-thiadiazole-based poly(2,5-dithienylpyrrole) derivatives

PBDTA/PProDOT-Et₂ ECD showed high ΔT_max (43.8%) and satisfactory cyclic voltammetry stability, whereas P(BDTA-co-DTP)/PProDOT-Et₂ ECD showed high ΔT_max (44.0%) and coloration efficiency (504.6 cm² C⁻¹).

Synthesis and electro-optical properties of new conjugated hybrid polymers from EDOT end-capped dibenzothiophene and dibenzofuran

Two novel EDOT end-capped dibenzo five-membered ring-heterocycle hybrid polymers were synthesised and their optoelectronic properties were explored.

Electropolymerized three-dimensional randomly branched EDOT-containing copolymers

The potential of 2,2';3,2″-terthiophene (3T) as branching units in 3D copolymers is presented with EDOT as an example comonomer. Branched EDOT/3T polythiophenes were prepared by electropolymerization, and their electrochemical and optical properties are discussed. Two different approaches were employed: (i) the direct electropolymerization of a novel branched thiophene monomer (3TE3) consisting of a 3T core that contains three outer EDOT end groups and (ii) the electrochemical copolymerization of a EDOT/3T mixture in different ratios from [1:1] to [1:10]. Cyclic voltammetric and vis spectrometric experiments show that the EDOT content within the polymer has a strong influence on the electronic properties of the material: with increasing EDOT content, the HOMO-LUMO gap is decreased. To prove copolymer formation of EDOT and 3T, chemically synthesized reference copolymers of EDOT and 3T were prepared by oxidative coupling using FeCl3, and their optical and electronic properties were compared to those of the electrodeposited films. In addition, the copolymer formation is indicated by the comparison of the electrochemical and spectroscopic results with those of the homopolymers P3T and PEDOT.

An Improved Procedure for the Synthesis of 3,4-ethylenedioxythiophene

An improved procedure for the synthesis of 3,4-ethylenedioxythiophene is reported starting from ethyl chloroacetate. Reaction with sodium sulfide gave diethyl thiodiglycolate which was then reacted with diethyl oxalate, and then 1,2-dibromoethane to give 2,5-dicarbethoxy-3,4-ethylenedioxythiophene. Hydrolysis, and decarboxylation gave 3,4-ethylenedioxythiophene in 16% overall yield. The structures of the key intermediates in synthetic routes were confirmed, and every step was optimised, to give a procedure suitable for large-scale industrial production.