PEDOT nanorods

The unique property of conjugated polymers to uptake/release the anions upon transformation from oxidized to reduced state can be used for the targeted deposition of NPs. To demonstrate the principal viability of such approach, VCL/AAEM/PEDOT microgels have been used as templates for the incorporation of AuNPs [148], Figure20 shows the procedure of AuNP deposition into microgels filled with PEDOT nanorods. 

Fig. 20 Selective AuNPs deposition on PEDOT nanorods in microgel structures (a) PEDOT nanorods are not fully oxidized and attract a small amount of counterions (green circles). The small amount of positively charged groups (red circles) are due to the incorporation of initiator residues into polymer chains of microgel. (b) After addition of H+, [AuCU]- PEDOT nanorods become oxidized in acidic pH and [AuCLt]" anions (yellow circles) are drawn into the microgel to compensate for a charge on the nanorod surface (white circles), (c) After addition of NaBH4 and a reduction process, AuNPs are predominantly formed on the PEDOT nanorod surface. Taken from [148], Copyright Wiley-VCH. Reproduced with permission...

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... 

Figure 19 TEM images of microgel particle, microgel filled by PEDOT nanorods, and microgel/PEDOT/AuNPs composite. Reproduced with permission from Main, J. Schrinner, M. Lu, Y. Small, P. A. 2008,4,2016-2024 Main, J. Eckert, F. Pich, A. Adler, H. J. Macromol. RapidCommun. 2008,29,472-47 8 234.235 Copyright Wiley-VCH Verlag GmbH Co. KGaA.

Shinkai et al. used the superstructures of anionic porphyrin (5-, 10-, 15-, 20-tetrakis(4-sulfonatophenyl)porphyrin, TPPS) as the template, because porphyrins tended to aggregate into a 1-D rod-like structure [372], J-aggregates of TPPS immobilized on ITO substrates were confirmed by UV-vis absorption at 489 nm. They also demonstrated the influence of TPPS on the formation mechanism of PEDOT nanorod. PEDOT films were prepared after 10, 30 and 60 cycles in the presence of TPPS and after 10 cycles in the absence of TPPS. When TPPS was not applied into solution, nanorodlike morphology was not found. Therefore, it could be concluded that TPPS played an important role in forming J-aggregates as the template. The dimension of PEDOT nanorod was 300-500 nm in length and 30-50 nm in diameter. Slow scan rate led the PEDOT nanorod to form less ordered structure in the film layer. 

Fig. 6 The sensitivity change of PEDOT nanorods and conventional PEDOT films as a function of a NH3 and b HCl vapor concentration, and the reversible and reproducible response of PEDOT nanorods upon periodic exposure to c NH3 and d HCl vapor (reproduced with permission from [369])...

P3HT ITO/PEDOT PSS/P3HT Ti03(nanorods, oleic acid)/ TiOj(nanorods)/Al 0.64 2.73 56 0.98 2008 [107]... 

It was shown that the Seebeck coefficient of the PEDOT PSS/Te hybrid is significantly larger than that of the pure PEDOT PSS polymer. Besides, electrical conductivity of the hybrid films is also higher than those of both the Te nanorods and PEDOT PSS polymer, indicating that the PEDOT PSS protects the Te from oxidation and improves inter particle contact. By varying the Te content, it was found the electrical conductivity and the TE power factor of the composite exhibit a peak at an intermediate nanowire mass fraction, whereas the Seebeck coefficient increases monotonically with increasing Te, as shown in Figure 6.37 [17]. 

Fabrication methods for 1-D PEDOT structures such as nanorod, tube and wire have been proposed via various synthetic routes microemulsion polymerization, template synthesis, electrochemical polymerization, and so forth. In the case of the template synthesis, various commercial templates were produced and available currently such as track-etched PC and AAO membranes, and mesoporous sihca. 

Recently, PEDOT nanomaterials have been fabricated in the shape of rods, tubes, thimbles, and belts through chemical polymerization in the pore of AAO membrane [368]. EDOT-fiUed AAO membrane was employed to overcome the poor solubility of EDOT monomer in water and the difficulty in controlling the reaction time. Chemical polymerization has been accom-pUshed by transferring EDOT-fiUed AAO membrane into an aqueous oxidant solution. EDOT monomer was retained in the pore of the AAO due to the extremely low solubility of EDOT in the aqueous solution. The elevated polymerization temperature and high concentrated FeCb solution increased the rate of polymerization, which resulted in the augment of wall thickness. Under these conditions, different nanostructures of PEDOT such as belt-like structure, thimble-like structure and nanorod were reaUzed by different FeCU concentration and polymerization temperatures. 

Souze et al. have fabricated the solid electrolyte-based supercapacitor based on SWCNTs/PANI on polyethylene terephthalate-PET substrates. They have used H2SO4-PVA gel electrolyte and measured the pseudocapacitive properties and estimated the coulometric specific capacitance of 76.7 F cm [87]. The poly (3,4-ethylenedioxypyrrole) and PEDOT wrapped Sb2S3 nanorods were synthesized hydrothermally by Reddy et al. [88] and 1008 F/g specific capacitance, 504 W/kg power density, and 88 % capacitance retention over 1000 cycles were estimated in the fabricated supercapacitor. Further, the supercapacitor was fabricated using semisolid electrolyte using PMMA in ionic liquid. 

Single crystalline LiFeP04 nanorods of length 1 pm and width 40 nm with orthorhombic crystal structure a = 10.320 A, b = 6.000 A, c = 4.697 A was synthesised by Murugan et al. [46]. Since LiFeP04 have poor electronic and ionic conductivities, these nanoparticles were subsequently coated by a mixed ionic-electronic conducting polymer, PEDOT (p-toluenesulphonic acid doped... 

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