Copolymers of PEDOT

which has reactive methacrylate endgroups, is dispersible in an organic solvent such as nitromethane or propylene carbonate. Films cast from these solutions are smooth and scratch resistant and have good adhesion properties on many substrates. And thin films appear transparent blue with an optical transmittance up to 75 /o.i 4 

Depending on what anion is used to dope these copolymers, bulk conductivity is measured in the O.l-l.O S/cm range (Aedotron -C) or 10-60 S/cm (Aedotron -C3) (Fig. 3.24 Table 3.3).  

Cast films can exhibit a wide range of sheet resistance, depending on film thickness, preparation method, and material choice. 

The graph in Fig. 3.25 shows a plot of the visible transmittance of cast thin films of Aedotron -C that were dip-coated on polycarbonate from a propylene carbonate dispersion and dried at 80°C. The sheet resistance of each film is also shown in the graph. 

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Figure 3.23 Block copolymers of PEDOT with flexible polymers.

In the meantime, this phenomenon has also been observed by other groups for thermosensitive polymer-based metal nanoparticles [77, 78]. Pich et al. have used microgel particles based on the copolymer of A-vinylcaprolactam (VCL) and ace-toacetoxyethyl methacrylate (AAEM) (PVCL/PAAEM) as the carrier system for the deposition of metal nanoparticles. The microgels were first modified with poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods through an in situ oxidative polymerization process. Microgels with PEDOT nanorods in the shell were then used for the... 

Other studies in 2000 by Drew et al. reported that it is very difficult to spin fibers of PANI complexed to sulfonated polystyrene (PANFSPS), even when solutions containing sodium chloride and dodecyl benzene sulfonic acid sodium salt were used to lower the surface tension and thereby enhance electrospinning [16,17]. However, PANFSPS nanofibers can be produced by adding a carrier polymer such as PEO, polyacrylonitrile, or polyurethane. Also reported was the use of electrostatically layered sulfonated polystyrene as a template for the surface polymerization of conjugated polymers in their conducting form. Enzymatic synthesis of PANI and a copolymer of pyrrole and PEDOT was done on electrospun nanofiber... 

Spencer, H.J., P.J. Skabara, M. Giles, I. McCullough, S.J. Coles, and M.B. Hursthouse. 2005. The first direct experimental comparison between the hugely contrasting properties of PEDOT and the all sulfur analogues PEDTT by analogy with well-defined EDTT-EDOT copolymers. /Mater Chem 15 4783-4792. 

A regioregular homopolymer of 3-nonylthieno[3,2-Z>]thiophene was also prepared (Table 17.1, 10) however the molecular weight was low and no evidence of thermal transitions was observed by DSC [51]. Charge transport characteristics were not reported. The homopolymer of 3,6-dimethoxythieno[3,2-f>]thiophene [53] and copolymers of 3,4-dialkoxythieno[2,3-f>]thiophene [54] have recently been reported as a possible alternative to the conducting polymer ethylenedioxythiophene (PEDOT). Co-polymers of thieno[3,2-Z>]thiophene [55-57] and thieno[2,3-f>]thiophene [58] with 9,9-dialkyl fluorene have also been reported for both transistor and OLED applications. In the case of the thieno[3,2-b]thiophene copolymer, the polymer exhibited thermotropic liquid crystalline behavior with a nematic phase at high temperature [59]. p-Type field effect mobilities in transistor devices were on the order of 1 x 10 cm V s . Although the value is on the low side of acceptable performance, a comparison to the well-studied... 

Poly (thiophene)s are of particular interest as electfochromic materials owing to their chemical stability, ease of synthesis and processability. For the most part, current research has been focused on composites, blends and copolymer formations of several conjugated polyheterocyclics, polythiophene and its derivatives, especially PEIX)T. In one example, poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(2-acrylamido-2-methyl-l-propanesulfonate) (PAMPS) composite films were prepared by Sonmez et al. for alternative electrochromic applications [50]. Thin composite films comprised of PEDOT/PAMPS were reported to switch rapidly between oxidized and neufial states, in less than 0.4 s, with an initial optical contrast of 76% at A.max. 615 nm. Nanostructured blends of electrochromic polymers such as polypyrrole and poly(3,4-ethylenedioxythiophene) were developed via self-assembly by Inganas etal. for application as an electrochromic window [26]. Uniir etal. developed a graft-type electrochromic copolymer of polythiophene and polytetrahydrofuran for use in elecfiochromic devices [51]. Two EDOT-based copolymers, poly[(3,4-ethylenedioxythiophene)-aZ/-(2,5-dioctyloxyphenylene)] and poly[(3,4-ethylenedioxythiophene)-aft-(9,9 -dioctylfluorene)] were developed by Aubert et al. as other candidates for electrochromic device development [52],... 

Dual-type polymer electrochromic devices based on copolymers of 2-benzyl-5,12-dihydro-27f-pyrrolo [3, 4 2,3] [1, 4]dioxocino[6,7-6]quinoxaline (DPOQ) and 5,12-dihydrothieno[3, 4 2,3] [1, 4]dithiocino [6,7- >]quinoxaline (DTTQ) with bithiophene were developed. P (DPOQ-co-BT) and P(DTTQ-co-BT) were used as the anodically coloring and PEDOT as the cathodically coloring electrochromic materials [81]. Each device performed with a favorable switching time, optical contrast, open-circuit memory and stability. 

The carboxylic acid moiety is not sufficient to give— after neutralization— water soluble, so-called self-doping PEDOT derivatives. Copolymers of EDOT-CH2O-CH2-COOH (the carboxylic acid in Figure 12.6) with EDOT and... 

SCHEME 2.15 Dependence of the electroluminescence of alkoxyphenyl-PPV copolymers on the comonomers ratio (PLED configuration ITO/PEDOT or PANI/polymer/Ca or Yb/Ag). 

Likewise, copolymers 90 have higher EL efficiency than homopolymers DHF-PPV 57 or MEH-PPV 13, due to more balanced charge injection and transport properties. Copolymer 90 with 7.5 wt% loading of dialkoxyphenylene comonomer gave the highest QE. The device with an ITO/PEDOT/90/Ca configuration showed remarkably higher efficiency (2.4cd/A) than devices fabricated with other copolymers in the series (0.65-1.0cd/A) [141],... 

The diphenylamino-substituted PPV107, with solubilizing alkoxy groups, was synthesized by Shi and Zheng [150] via Wittig-Horner reaction (Chart 2.23). Its PL (555 nm) is very similar to that of diamino-PPV 64 and dialkoxy-PPV 14 homopolymers. The PLQY is rather high in solution (80%), but it drops to only 8% in films. Consequently, only a moderate EL efficiency of 0.6cd/A was obtained with this material (device ITO/PEDOT/107/Mg/Al) [150]. Almost simultaneously, Kido and coworkers [151] reported a similar diphenylamino-substituted PPV copolymer 108, which affords very efficient PLEDs. The device ITO/PEDOT/108/Ca/Al... 

Neumann and coworkers [165] synthesized tetrafluorinated-PPV copolymer 133 and studied its light-emitting properties. However, this material was quite unsuccessful for LED applications increasing the amount of fluorinated comonomer resulted in a dramatic decrease of the PLQY and the turn-on voltage of the devices was above 30 V (which could only be realized in ac mode due to device shorting). The quenching was less pronounced for an analogous copolymer with MEH-PPV (134), which showed an EL efficiency of up to 0.08 cd/A (in ITO/PEDOT/134/Ca diode) [166] (Chart 2.26). 

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