Poly 3- -2,2 -bithiophene

Fig. 1 Building units of conducting polymers, (1) polyacetylene (PA) (2) polypyrrole (PPy), polythiophene (PTh), polyfurane (PFu) (3) polyphenylene (PP) (4) polyaniline (PANI) 5 polyindole (PIND) (6) polycarbazole (PCaz) (7) polyazulene (Paz) (8) polynaphthalene (PNa) (9) polyanthracene (PAnth) (10) polypyrene (PPyr) (11) polyfluorene (PFiu) (12) poly(isothionaphthalene) (PITN) (13) poly(dithienothiophene) (14) poly(thienopyrrole) (15) poly(dithienylbenzene) (1G) poly(3-alkylthiophene) (17) poly(phenylene vinylene) (18) poly(bipyrrole) (PBPy), poly(bithiophene) (PBT) (19) poly(phenylenesulfide) (20) 4-poly(thienothiophene) (21) poly(thienyl vinylene), poly(furane vinylene) (22) poly(ethylenedioxythiophene) (PEDOT).

Thickness of the barrier layer, optimized at 220 nm [133], played a crucial role with respect to the chemosensor sensitivity, selectivity and LOD. So, eventually, the chemosensor architecture comprised a gold-film electrode, sputtered onto a 10-MHz resonator, coated with the poly(bithiophene) barrier layer, which was then overlaid with the MIP film. This architecture enabled selective determination of the amine at the nanomole concentration level. LOD for histamine was 5 nM and the determined stability constant of the MIP-histamine complex, XMn> = 57.0 M 1 [131], compared well with the values obtained with other methods [53, 136, 137]. Moreover, due to the adopted architecture, the dopamine chemosensor could determine this amine with the stability constant for the MIP-dopamine complex, XMip = (44.6 4.0) x 106 M-1 and LOD of 5 nM [133], which is as low as that reached by electroanalytical techniques [138]. The MIP-QCM chemosensor for adenine [132] also featured low, namely 5 nM, LOD and the stability constant determined for the MIP-adenine complex, XMIP = (18 2.4) x 104 M, was as high as that of the MIP-adenine complex prepared by thermo-induced co-polymer-ization [139]. The linear concentration range for determination of these amines extended to at least 100 mM. 

Poly(bithiophene) films from these two ionic liquids are morphologically similar (Figure 7.14), even though the redox behavior (Figure 7.9) is markedly different, suggesting that the dominant differences in the films produced are on an atomic or sub-micron rather than macroscopic level. The morphology ofthe poly (bithiophene) films appears to be similar to that described by Roncali et al. [74] who reported a thin film on the surface of the electrode, covered by a thick brittle powdery deposit, from the galvanostatic polymerization of bithiophene in acetonitrile. The nodular structures are smaller in the poly (bithiophene) films than in the poly (thiophene), which is consistent with the formation of shorter chain polymers [73], but this does not... 

Fig. 7.14 SEM images of poly(bithiophene) ((a) and (b), 10pm, (c) and (d) 2pm edge-view) and poly(terthiophene) ((e) and (f), 10pm) grown from [C2mim][NTf2] (a), (c), (e) and [C4mpyr][NTf2]...

Sarac et al. [98] for poly(terthiophene) grown in acetonitrile, but without the large amount of powdery deposit observed in the poly(bithiophene) films (Figure 7.14(a, b)). Again, the film from the pyrrolidinium ionic liquid appears to be slightly more compact. 

Table I. Chemical Analysis for Poly Bithiophene Perchlorate...

M. Baibarac, I. Baltog, and S. Lefrant, Raman spectroscopic evidence for interfacial interactions in poly(bithiophene)/single-walled carbon nanotube composites. Carbon, 47, 1389-1398 (2009). 

Photoelectrochemical measurements (introduced in Chapter 9) corroborate and extend capacitance measurements. Photocurrent spectra of poly-bithiophene are shown in Figure 11.23. The spectra are shown for different solvents. The highest photocurrents (largest quantum-chemical efficiency) were observed in acetonitrile, which decreased with an increasing amount of water. 

Figure 11.24 Dependence of the photocurrent of a poly-bithiophene film on the potential (at 2.5 eV), 0.1 mol-dm LiBp4, 2 = 500 nm, and light intensity 120 mW-cm . ...

Figure 11.30 CycUc voltammograms of (a) polypyrrole, (b) poly-bithiophene, (c) the copolymer formed at 1.1 V versus SCE in acetonitrile, monomer ratio Py BTH = 1 10, and (d) the copolymer formed at 1.1 V versus SCE in acetonitrile, monomer ratio Py BTH = 1 20. ...

Preformed polymers bearing a reactive or activated group that can react with a functional group of an enzyme have been reported. Schuhmann described the synthesis of polymers 130 and 131 derived from dithienylpyrrole containing a pendant amino group that can fix a glucose oxidase [244]. Bauerle and coworkers have developed poly(bithiophene) 132 and the related poly(terthio-phene) substituted with easily replaceable N-hydroxysuccinimide ester [245] for the immobilization of glucose oxidase [246]. 

Another interesting example of well-structured 3D ECPs is provided by Bartlett et al., who used PS latex beads as colloidal templates to electrosynthesize highly ordered macroporous PPy, PANI, and poly(bithiophene) [304]. 

M. Schaferling and P. Bauerle, Synthesis and properties of porphyrin-functionalized poly(bithiophenes), Synth. Met., 101, 38-39 (1999). 

Alternating copolymers of thieno[2,3-6]thiophene and 4,4 -dialkyl-2,2 -bithiophene, referred to as pBTCT [poly(Bithiophene-crossconjugated thiophene)] were also designed and synthesized (Table 17.1,8) [52]. The most stable backbone conformation for these polymers requires that, where possible, the sulfurs in adjacent backbone units arrange in an anti configuration in order to maximize the spatial separation... 

Mesopores Poly(bithiophene), poly (3 -dodecylthiophene) Electrochemical Pore filling Schultze and Jimg (1995), Errien et al. (2005)... 

As stated earlier, polymer deposition occurs by precipitation of the oligomers when their chain length attains a value of critical solubility [38]. The growth of PT and poly(bithiophene) has been studied by time-resolved ultraviolet visible (UV-vis) spectroscopy. Comparison of the spectra of the reaction solution with those of authentic neutral thiophene oligomers has led to the conclusion that oligomers formed by 7-12 monomer units are formed in solution during electropolymeriza-... 

Hence we see that this scheme provides a very convenient method for isolating the rate-determinint step in the redox-switching process. The analysis has been applied to redox switching in poly(bithiophene) films " and poly(vinylferrocene) layers. " The reader is referred to these papers for further details. 

The same approach has been successfully used to interprete voltammo-grams of poly(bithiophene) at various temperatures/ ... 

Two main factors have motivated the use of these compounds as starting monomers in the polymerization of thienyl oligomers. One is the lower polymerization potential of bithiophene and a-terthienyl. The second is that poly(bithiophene) and poly(a-terthienyl) are ex-... 

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