3-butylthiophene

Against this background of infusible conducting polymers, the development of the soluble polythiophenes is most interesting. Glass transition temperatures have been reported as 48 °C for poly(3-butylthiophene) and 145 °C for poly(3-methyl-thiophene) 261). These polymers also show crystallinity in films and can be crystallized from solution. Solution studies indicate that there are two chain conformations 262) and the availability of a non-conjugated conformation may be a key to the low transition temperatures and solubility, when compared to the stiff-chain conjugated polymers. 

Despite the fact that optical applications require thin films of poly(3-alkylthiophene)s, the photochemistry of these materials has been characterized in solution but only scarcely in the solid state. The UV/Vis spectra of these films of poly(3-butylthiophene) show an absorption band in the visible range corresponding to a n—n transition whose energy depends on 7r-electron delocalization. 

To improve the perpendicular orientation of the film, 5-cyano-2-(butyl-4-phosphonic acid)-3-butylthiophene (CNBTPA) (Scheme 5.1) was also designed to work as a template layer in order to promote a defined orientation of the oligothiophene layer. Compared to other concepts using a template layer... 

Parashkov, R. et al.. All-organic thin-fihn transistors made of poly(3-butylthiophene) semiconducting and various polymeric insulating layers, J. Appl. Phys. 95, 1594-1596, 2004. 

Alkyl- or aryl substituents in the 3-position do not have a directing influence and metallation in the 2- and 5-position occurs with comparable rates [1]. 3- -Butylthiophene however, is metallated exclusively at C-atom 5 [139]. 

Several modified phthalocyanine compounds have been found to effectively stabilise rubber/ Other unusual stabilisers include piperylene-methyl-styrene in poly(ethylene), dioxynaphthylpropane in polyfethylene), ketones and anilines for poly(3-butylthiophene), thioglycerol for wood pulp and dibutylphthalate for PMMA/ N-Arylphthalimides are self stabilising due to their donor-acceptor energy transfer properties/ ... 

Figure 4.1. H NMR spectrum of poly(3-butylthiophene) in CDCI3. (Reproduced from Synih. Mel. 58, 295 (1993), B. Krische, M. Zagorska and J, Hellberg, Copynght 1993, with kind permission from Elsevier Science S.A., Lausanne. Switzerland.)...

Results obtained with poly(3-octylthiophene) and poly(3-butylthiophene) mixed with poly(ethyl-vinyla-cetate are given in Figure 8.15. although the samples of Figure 8.15(a) and (b) have conductivity levels similar to the polyaniline of Figure 8.13, the maximum of M" and the saturation of M are not observed. In fact, due to a very large distribution of relaxation times and then... 

Elemental analyses of the materials obtained were in good agreement with theoretical results. A residual amount of Fe was found in materials synthesised by FeCl3 oxidation. This leads to an atomic radio [Fe]/[S] of 0.011 for poly(3-butylthiophene) and of 0.029 for poly(3-octylthiophene) for the as-synthesised polymers. 

Y. Wang, Z. Chen, J. Chen, Y. Qu, X. Yang, Miscibility, crystallization, and morphology of the double-crystalline blends of insulating polyethylene and semiconducting poly (3-butylthiophene). J. Macromol. Sci. Part B Phys. 52, 1388-1404 (2013)... 

K. Poly(3-butylthiophene) (PBT), poly(3-octylthiophene) (POT), and poly(3-decylthiophene) (PDT) have so far been characterized only at room temperature. 

A regiorandom copolymer of 3-methylthiophene and 3-butylthiophene possessed a conductivity of 50 S/cm, while a more regioregular copolymer with a 2 1 ratio of HT to HH couplings had a higher conductivity of 140 S/cm. Films of regioregular poly[3-(4-octylphenyl)thiophene] (POPT) with greater than 94% HT content possessed conductivities of 4 S/cm compared to 0.4 S/cm for regioirregular POPT. 

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