Poly alkanesulfonates

Alkanesulfonates are widely used as an internal antistatic agent for poly(vinyl chloride) (PVC). Since alkanesulfonates cause hazing of unplasticized PVC in the normally used quantities of 1.0 to 1.5 parts per hundred parts resin (phr), its main use is in the manufacture of opaque PVC-calendered film. To produce transparent unplasticized articles, the addition of alkanesulfonates should not exceed 0.3 phr. Figure 40 shows the antistatic effect of alkanesulfonates in PVC. 

Arroyovillan, M.I. et ah, Poly(N-(3-thienyl)alkanesulfonates) Synthesis, regioregu-larity, morphology, and photochemistry. Macromolecules 28, 975-984, 1995. 

Wudl and Heeger et al. prepared the self-dopable polymers poly(n-(3 -thienyl)alkanesulfonic acids) (P3TASH) and their sodium salts with alkane chain lengths ranging from 2 to 4 [127-129]. In an extension of this study, Ikenoue et al. found that poly(3-(3 -thienyl)propanesulfonic acid) (P3TPSH), which was obtained by exchanging the sodium ions in poly(sodium-3-(3 -thienyl)propanesulfonate) (P3TPSH) with protons... 

Figure 1.31 Basic units of poly(n-(3 -thienyl)alkanesulfonic acid). (Reprinted with permission from Macromolecules, 26, 7108. Copyright (1993) American Chemical Society.)...

S. A. Chen, M. Y. Hua, Structure and doping level of the self-acid-doped conjugated conducting polymers - poly(n-(3 -thienyl)alkanesulfonic acid)s, Macromolecules 1993, 26, 7108. 

Wudl and Heeger et al, [17] electrochemically synthesized the sodium salts and acid forms of poly(3-thiophene ethanesulfonate) and poly(3-thiophene butanesulfonate). The monomers 3-thiophene ethanesulfonate and 3-thiophene butanesulfonate were prepared by the route shown in Figure 4.1. However, attempts to electropolymerize these monomers or their sulfonic acid derivatives were not successful. Therefore, the monomers, 3-thiophene alkanesulfonate methyl esters, were polymerized first, followed by conversion of the ester to the sodium salt via the sulfonyl chloride derivative. The sodium salts of poly (3-thiophene ethanesulfonate) and poly( 3-thiophene butanesulfonate) are reportedly soluble in water in their neutral (insulating) and doped (conducting)... 

Chen et al. [24] studied the structure and effect of the side chain length on the doping level of self-doped poly(n-(3 -thienyl)alkanesulfonic acid)s with alkanes of carbon numbers 2, 6 and 10. They suggested that self-doping of poly(n-(3 -thienyl)alkanesulfonic acid)s is dependent on the side chain length (for details see Chapter 1 Section 1.4.3). In subsequent work, Chen et al. reported the irreversible thermal dedoping... 

Holdcroft et al. [38] prepared the sodium salt and acid forms of poly(n-(3 -thienyl)alkanesulfonates) following the Ikenoue et al. chemical synthesis method mentioned above [21]. The aim of this study was to... 

The conductivities of the self-doped acid forms of poly(n-(3 -thienyl)-alkanesulfonates) were in the range of 5 x 10 -10 S/cm. The sodium salt and acid forms of poly(n-(3-thienyl)alkanesulfonates are reportedly completely water soluble. The absorption spectra of aqueous solution of sodium salt of poly(n-(3 -thienyl)alkanesulfonates) containing propane-sulfonate, hexanesulfonate and octanesulfonate substituents show n-n transitions at 436, 446, and 466 nm, respectively. It was suggested that the red shift in absorption spectra with increasing side-chain length is... 

The same applies to the ion-pair chromatographic separation of cations, which is performed either with long-chain alkanesulfonic acids or, in the simplest manner, with mineral acids. A survey of the most commonly used reagents is listed in Table 6.1 in the order of increasing hydrophobicity. A comparison by Cassidy and Elchuk [18] of chemically bonded reversed phases with organic divinylben-zene-based (Dionex lonPac NSl) versus phases with poly(styrene-co-divinylben-zene)-based polymers (Hamilton PRP-1) revealed that the latter have a lower... 

Figure 20.1. Oxidation of poly(oj-(3-thienyl)alkanesulfonates) illustrating the mechanism of self-doping.

Preliminary investigations of self-doped polythiophenes did not specify whether the cation species associated with the sulfonate group was expelled or whether an additional anion was incorporated during electrochemical oxidation of the polymer. Using cyclic voltammetry, pH measurements, and atomic absorption spectroscopy, it was established that the hydrogen ion associated with poly(cu-(3-thienyl)alkanesulfonic acids... 

Ikenoue et al. were the first to offer an explanation of auto-doping [11]. They observed that poly(o>-(3-thienyl)alkanesulfonic acids) are extremely hygroscopic and thus films of the polymer contain moisture. In the presence of moisture, the acidic proton is solvated by water molecules. When water is removed by heating, the next most basic unit able to coordinate acidic protons is the polythiophene backbone itself as shown in Figure 20.11. Protonation of the backbone creates a polaronic residue on the polymer chain. This phenomenon is obviously not observed for the sodium salt, and hence the sulfonic acid form of the polymers exhibits a higher conductivity in its electrochemically neutral state than the corresponding sodium salt. 

X-ray diffraction analysis shows that poly(co-(3-thienyl)alkanesulfonates) (P3TASs) are amorphous. Amorphology in poly(3-alkylthiophenes) can result... 

Figure 20.23. Photolithographic scheme for obtaining negative images of poly(c )-(3-thienyl)alkanesulfonates). (Reprinted by permission of ref. 9)...

Havinga et al. prepared a series of poly(o)-(pyrrol-3-yl)alkanesulfonates) for electrochemical study [7] (Figure 20.34). Their synthetic route involved protecting the A-position with benzenesulfonyl chloride to form the A-phenylsulfonyl derivative. The pyrrole was then acylated at the 3-position of pyrrole with a o>-haloacid chloride under Freidel-Crafts conditions, followed by a Clemmensen reduction to yield the... 

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