Structural Study of Doped and Undoped Polythiophene in Solution by Small-Angle Neutron Scattering

Polaron‐induced conformation change in single polypyrrole chain: An intrinsic actuation mechanism

“…This suggests a possible single-chain actuation mechanism driven by oxidation and reduction processes. The mechanism is intrinsic since interchain interactions or counterions are not required; it offers a physical interpretation of the large conformation changes observed in doped single poly-3-butylthiophene chain by small-angle neutron scattering [6]. (Conjugated polymers are widely studied for their actuation properties, but in the devices demonstrated to date the actuation has been primarily due to ion and solvent insertion [30,31].)…”

“…(Conjugated polymers are widely studied for their actuation properties, but in the devices demonstrated to date the actuation has been primarily due to ion and solvent insertion [30,31].) Because it does not involve ion intercalation, the actuation process could be extremely fast; namely, this mechanism may add to our repertoire of molecular machines, such as molecular elevator [6] and single carbon nanotube [32]. Strain measurements in single nanotubes using a conducting AFM tip suggest an approach for experiments on helical oligomers.…”

“…© 2005 Wiley Periodicals, Inc. Int J Quantum Chem 102: 980 -985, 2005 Key words: polypyrrole; conjugated polymer; polaron; conformation; actuation mechanism; helix H elical structures have recently attracted much interest in the field of -conjugated polymers [1][2][3][4][5]. Helices may arise for a variety of reasons, such as hydrogen bonding [4], steric interactions between sidechains [5], twisting with a polymeric dopant, or polymerization in a chiral medium [2,3].It was observed via small-angle neutron scattering that upon oxidation, single poly-(3-alkylthiophene) chains undergo large conformational changes from coils to rods [6]. Two questions are of interest: i) How does a single conjugated polymer chain form coils or even helices?…”

Model of a polymer chain twisted inside a statistical segment. Poly(3‐hexylthiophene) in chloroform solutions

“…along the direction of extension of the molecule as a whole) is almost twice as high as the linear mass density of a molecule ( M 0 / λ ) along the direction of its backbone, i.e. along the main axis of the polymer molecule ( M L /( M 0 / λ ) = 1.833), where M 0 = 166 is the molecular mass of P3HT monomer unit and λ = 3.9 × 10 −8 cm is the monomer unit length . Thus, it is to be concluded that the backbone direction does not coincide with the spherocylinder axis.…”

On the Helical Motif of the Complexes Created by Association of Helix‐Forming Schizophyllan (SPG) and Helix‐Forming Polythiophene Derivatives

“…Recent experimental evidence showed, however, that a certain 3-substituted polythiophene adopts a fairly flexible coil structure. [8] In addition, calculations published by Cui and Kertesz indicated that the energy difference between anti and syn conformations is rather small and two possible helical backbone conformations (anti-type rod helix and syn-type coil helix) ( Figure 1) can be present. [9] More recently, Nilsson et al achieved the construction of left-and right-handed syn type helical polythiophenes, that is, poly(3-A C H T U N G T R E N N U N G [(R or S)-5-amino-5-carboxyl-3-oxapentyl]-2,5-thiophene hydrochloride) (d-or l-POWTs) by the introduction of free amino acid groups (Figure 2).…”