Copolymers cyclic voltammetry

The step 1 product and 2,2, 5,2"-terthiophene were reacted to form the copolymer using cyclic voltammetry and electro-copolymerizalion. Cyclic voltammetry in CH2CI2 containing 0.1 M tetrabutylammonium perchlorate supporting electrolyte indicated that the co-monomer oxidation began at approximately 0.70 V vs. Ag/Ag+. 

A summary of UV -Vis measurements and cyclic voltammetry testing results for silafluorenyl copolymers are provided in Tables 1 and 2, respectively. 

Cyclic voltammetry revealed that the N-atoms of 86a, 88a and 91a are oxidized at lower potentials than the trivalent P atoms. Comparison of these data with those observed with model compounds shows a very weak electronic delocalization via the P centers for copolymers 86a and 91a. In contrast, the low first oxidation potential observed for 88a (Table 4.5) is assumed to result from an electronic communication between the N moieties through the connecting P centers [59b]. The equivalence of the oxidation potentials for the oxidized polymers (Table 4.5) suggests the presence of electronically isolated triarylamine fragments in these derivatives. Note that the involvement of the P lone pair in jt-delocalization... 

Kapui et al. prepared a novel type of polypyrrole films [168]. The film was impregnated by spherical styrene-methacrylic acid block copolymer micelles with a hydrophobic core of 18 nm and a hydrophilic corona of 100 nm. The properties of the micelle-doped polypyrrole films were investigated by cyclic voltammetry and SECM. It was found that the self-assembled block copolymer micelles in polypyrrole behave as polyanions and the charge compensation by cations has been identified during electrochemical switching of the polymer films. 

Xia and Advincula have prepared copolymers 58 containing hole-transporting carbazole units by Yamamoto copolymerisation (Scheme 25) [165]. Cyclic voltammetry showed that the HOMO energy level increased from 5.8 eV to 5.6 eV with 10mol% carbazole and to 5.5 eV with 30 mol % car-... 

Figure 3.9 Shell-cross-linked nanotubes of PFS48-h-PMVS300 block copolymers (a) TEM image for the sample prepared for THF solution (b) cyclic voltammetry in dichloromethane benzonitrile (2 1) with 0.1M [Bu4N][PFg] as supporting electrolyte. (From Wang and Manners.26 Reproduced with permission.)...

Another hybrid MIP example is represented by the copolymerization of phenol with a covalently constructed complex between 3-hydroxyphenyl boronic acid (functional monomer) and monosaccharide (template). The copolymer was deposited on a gold electrode by cyclic voltammetry using two successive scans [46]. The obtained polymer presented an irregular morphology with an average thickness of 36 nm. 

The determination of the type of copolymers formed in the preparation process is an important characterization step. One method of characterization is cyclic voltammetry as shown, e.g., by Yohannes et Cyclic voltammograms of copolymerization of pyrrole and bithiophene is shown in Figure 11.30. 

Steel PM-ABA Cyclic voltammetry Tafel polarisation and EiS in IN HCl The protection efficiency of copolymer coating is three times higher than that of pure PANI. [20]... 

Copolymers with fluorene and 1,3,4-oxadiazole show highly efficient photoluminescence [105]. A double-layer device consisting of PVK and an alternating copolymer of 9,9 -didodecylfluorene-2,7-diyl and (l,4-bis-(l,3,4-oxadiazole)-2,5-di(2-ethylhexyloxy)phenylene)-5,5 -diyl exhibits a narrow blue electroluminescence with a maximum at 430 nm. Electrochemical analysis of the polymers using cyclic voltammetry suggests that they can be used both as electron transport materials and as blue emission materials for LEDs. 

FIGURE 18.11 Comparison of cyclic voltammetry (full Une) and in situ conductivities (dotted line) of (a) regioregular alternate copolymer of aniline derivative (b) with the random analogous copolymer. (Reprinted from Pullen, A.E., and T.M. Swager. Macromolecules, 34, 812—816, 2001. With permission.)... 

Electrochemical homopolymerization of poly(aniline-N-alkylsulfonates) (alkyl = propyl, butyl and pentyl) in acetonitrile containing 0.1 M NaC104 and 5 % (v/v) 0.3 M HCIO4 was carried out by Rhee et al. [144]. The polymers were prepared on a platinum electrode by cyclic voltammetry (0.0 to 1.0 V vs Ag/AgCl) or potentiostatic techniques (1.0 V). These polymers were found to form liquid crystalline solutions in water. The conductivity of poly(aniline-N-propanesulfonic acid) and poly(aniline-N-butanesulfonic acid) was reportly 9 x 10 and 6 x 10 S/cm, respectively. Electrochemical polymerization of orthanilic acid, metanilic acid and sulfonic acid and their copolymerization with aniline in dimethyl sulfoxide containing tetrabutyl ammonium perchlorate were carried out by Sahin et al. [145]. These polymers and copolymers were found to be soluble in water, dimethyl sulfoxide and N-methylpyrrolidinone. The conductivity of orthanilic acid, metanilic acid and sulfonic acid was reportly 0.052,0.087 and 0.009 S/cm, respectively. The conductivity of copolymers for these three isomers of aminobenzene-sulfonic acid was reported as 0.094, 0.26 and 0.033 S/cm, respectively. Sahin et al. [146] have also prepared the copolymers of these three isomers with aniline in acetonitrile containing fluorosulfonic acid (FSO3H). The copolymers were found to be soluble in water, dimethyl sulfoxide and N-methylpyrrolidinone. 

SCE). The ion exchange properties of these sulfonated copolymer films were evaluated for binding of cations like RufNHs) or U02 . The cyclic voltammetry and radiochemical measurements clearly showed the permanent cation exchange properties allowing efficient incorporation of cations like Ru(NH3)6 + or U02 . 

In 1995, Swager et al. synthesized the first calixarene-coupled diiodinated bithiophene, which afforded copolymer 2.166 (Chart 1.36) by Stille-type cross-coupling with distannylated 3,3 -bis(methoxyethoxy) bithiophene [263]. Selective recognition of Na+ ions was studied by UV-Vis spectroscopy and cyclic voltammetry. After addition of 0.5 mMNa+, cyclic voltammetric measurements showed a positive shift of the oxidation potential of about -1-100 mV with a simultaneous dramatic decrease in conductivity. This finding was attributed to an electrostatic effect of the Na+ ions and reduced electron-donating ability of the sodium bound oxygen atoms of the calixarene. 

Cyclic voltammetry (CV) is often used to determine the electrochemical properties of D-A copolymers. Usually, the CV setup consists of a Ag/AgNOs reference electrode, a platinum wire counterelectrode and a glassy carbon electrode with a drop-cast polymer film. First, the CV curve of ferrocene/ ferrocenium redox couple (Fc/Fc ) should be measured to calibrate the reference electrode. The polymer s HOMO energy level in electron volts is calculated from the onset of the oxidation peak ( ox) according to eqn (15.4). If the reduction peak of polymer is not clearly visible, the LUMO level can be approximated from the HOMO measured by CV and the bandgap measured by UV-vis. 

Andrieux, C. R, and Audebert, R, Synthesis and cyclic voltammetry of pyrrole copolymers substituted by anthraquinone, phenothiazine or anthracene moieties, J. Elec-troanal. Chem., 285, 163-175 (1990). 

Using cyclic voltammetry, Wei et al. [63] established that the materials obtained are really the copolymers of aniline with toluidine rather than a mixture of the... 

Cyclic voltammetry of the copolymer shows three anodic peaks, two matching the oxidation potentials of the parent homopolymers and a third which is intermediate. Authors attributed the data to the formation of blocks of polypyrrole and polythiophene cormected by blocks of random alternating groups of pyrrole and bithiophene. Increasing the amount of bithiophene in the copolymer produced a strong drop in the final conductivity of the materials, from 17 S cm at 1 mol% to I S cm at 14 mol%. 

Forced Rayleigh scattering can be used to measure the z-average diffusion coefficient of a PAT in dilute solution. For POT in trichlorobenzene, the diffusion coefficient D = 8 x 10 cm s" and hence the hydrodynamic radius of POT is about 130 A [156]. For copolymers of bithiophene and pyrrole, cyclic voltammetry (cf. Sect. 3.2.1) and UV/vis data support the formation of copolymers, which consist of three distinct oxidizable (dopable) units (i) short blocks of bithiophene units, (ii) short blocks of pyrrole units, (iii) random and alternating groupings of bithiophene and pyrrole [157]. 

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