Chromic effects and molecular weight in poly(3-alkylthiophenes)
01 Jun 1999-Journal of Materials Science Letters (Kluwer Academic Publishers)-Vol. 18, Iss: 12, pp 971-973
About: This article is published in Journal of Materials Science Letters.The article was published on 1999-06-01. It has received 5 citations till now. The article focuses on the topics: Solvent effects & Conductive polymer.
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33 citations
TL;DR: In this article, the yield and molecular weight of CHCl 3 poly(3,3″-didodecyl-2,2′:5′,2″-terthiophene) in the presence of FeCl 3 were shown to depend strongly on quality and addition rate of the reagents, and on temperature.
15 citations
Dissertation•
12 Jul 2017
TL;DR: In this paper, a methode de dosage des alcaloides par MALDI dans des extraits vegetaux and without pretraitement prealable a ete etudiee.
Abstract: Mon travail de these a consiste a poursuivre le developpement et l’application des matrices bithiopheniques specifique aux alcaloides. Apres l’optimisation d’un protocole efficace d’analyse, adapte a l’objectif de l’etude, la mise au point d’une methode de dosage des alcaloides par MALDI dans des extraits vegetaux et sans pretraitement prealable a ete etudiee. Cette methode a pu etre validee en etudiant des alcaloides existant dans differents extraits des plantes toxiques. Ensuite, la synthese et l’evaluation de nouveaux composes bithiopheniques ont ete presentes de maniere a evaluer les facteurs favorisant l’interaction avec les alcaloides. Ulterieurement, cinq nouvelles matrices interessantes furent l’objet d’une etude plus detaillee. Sur la base des resultats obtenus, le derive fluore F T3 s’avere le plus efficace. ll presente une meilleure selectivite que la matrice courante CHCA vis-a-vis des alcaloides et plus performant pour analyser les alcaloides dans differents melanges complexes tels que des extraits bruts de plantes, des insectes, et des solutions bio-actives commerciales (medicament et repulsif). A la fin, ces sont regroupes les resultats de l’etude des parametres thermodynamiques de la matrice MT3P, ce qui permettra de proposer des hypotheses expliquant la selectivite de la matrice bithiopheniques fonctionnalisee pour les alcaloides.
8 citations
References
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TL;DR: In this paper, a light scattering analysis of the colloidal solution of HT-P3HexTh in a 2:1 solution of CHCl3 and CH3OH reveals that the aggregated poly(3-alkylthiophene)s P3RThs and poly(4-alklythiazole) P4RTzs are aggregated in a parallel style.
Abstract: Stacking of poly(3-alkylthiophene)s P3RThs and poly(4-alkylthiazole)s P4RTzs has been studied. Light scattering analysis indicates that head-to-tail (HT) type HT-P3HexTh (R = n-C6H13) gives a degree of depolarization (ρv) of 0.26 in CHCl3, which reveals that HT-P3HexTh takes a stiff structure even in the good solvent. Addition of CH3OH to CHCl3 solutions of HT-P3HexTh and head-to-head (HH) type HH-P4HepTz (R = n-C7H15) leads to π-stacking of the polymer molecules to form stable colloidal particles. The light scattering analysis of the colloidal solution of HT-P3HexTh in a 2:1 solution of CHCl3 and CH3OH reveals that HT-P3HexTh is aggregated in a parallel style. Results of filtration experiments using membranes with 0.20 and 0.02 μm pores agree with the degree of the aggregation. P3HexThs with irregular structures (P3HexTh (Fe) and P3HexTh (Ni) with HT/HH ratios of about 7/3 and 1/2, respectively) show a weaker trend to aggregate; however, P3HexTh (Fe) is considered to stack in a surface region of a stretc...
484 citations
TL;DR: In this article, a series of cast films of poly(3-alkylthiophenes) (P3ATs, A = hexyl, octyl, dodecyl, and hexadecyl) with different head-to-tail (HT) diad content (70−100%) was studied.
Abstract: Thermochromism of a series of cast films of poly(3-alkylthiophenes) (P3ATs, A = hexyl, octyl, dodecyl, and hexadecyl) with different head-to-tail (HT) diad content (70−100%) was studied. The thermochromic behavior is found to be controlled by the HT diad content and the side chain length. P3ATs with moderate HT diad content give rise to a clear thermochromic isosbestic point irrespective of the length of the alkyl side chain. Regioregular polymers possessing a >90% HT diad content exhibit either a continuous thermochromic blue shift or an isosbestic point, depending on the alkyl side chain length. The different thermochromic characteristics are attributed to subtle morphological differences between the polymers. DSC and X-ray diffraction studies indicate that P3AT samples with moderate HT regularity are formally amorphous with a quasi-ordered phase dispersed in continuous disordered domains. P3ATs with high HT regularity consist of crystalline, quasi-ordered, and disordered phases. For polymers with short...
203 citations
TL;DR: The dependence of the intrinsic viscosity and the radius of gyration upon molecular weight M w (40000-220000) for poly(3-hexylthiophene) in THF dilute solution was found to be characteristic of a moderately good solvent as discussed by the authors.
Abstract: The dependence of the intrinsic viscosity and the radius of gyration upon molecular weight M w (40000-220000) for poly(3-hexylthiophene) in THF dilute solution was found to be characteristic of a moderately good solvent. Similar solution characteristics were observed in CHCl 3 . Macromolecular dimensions determined by different techniques indicate that this polymer exist as isolated flexible-coil chains in dilute THF solution with a persistance length of 2.4±0.3 nm.
167 citations
TL;DR: In this article, temperature-dependent optical absorption measurements have revealed important thermochromic effects in poly(3-dodecylthiophene) and poly( 3-octyloxythiophene), which are related to a planar to non-planar transition of the main polymer chain.
Abstract: Temperature-dependent optical absorption measurements have revealed important thermochromic effects in poly(3-dodecylthiophene) and poly(3-octyloxy-4-methylthiophene) between 25 and 150°C which are related to a planar to non-planar transition of the main polymer chain. This conformational transition is caused by an increase of the repulsive intrachain steric interactions upon heating, which then force the thiophene backbone to adopt a non-planar conformation. On the other hand, as observed with poly(3-octyloxythiophene), if the side chains do not lead to large steric interactions, the polymer can maintain a highly conjugated structure even at high temperatures while, if the steric interactions are too strong (e.g. poly(3,3′-dihexyl-2,2′-bithiophene)), no co-planar conformation can be adopted.
106 citations
TL;DR: In this article, temperature-dependent UV-visible absorption measurements have revealed reversible thermochromic effects (a 0.95-eV shift in the maximum of absorption) in amorphous poly[3-(octyloxy)-4-methylthiophene] (POMT).
Abstract: Temperature-dependent UV-visible absorption measurements have revealed reversible thermochromic effects (a 0.95-eV shift in the maximum of absorption) in amorphous poly[3-(octyloxy)-4-methylthiophene] (POMT). The presence of a solid-state «phase» transition was also confirmed by IR and DSC analyses. All these experimental results are consistent with a conformational transition of the conjugated polymer chain from a coplanar (rod) structure at room temperature to a nonplanar (coil) form at 150°C.
91 citations