Chain conformation of rod-like polymers in the melt: Small-angle neutron scattering of poly(benzoyl paraphenylene)

Vaia, Richard A.; Krishnamoorti, Ramanan; Benner, Charles L.; Trimer, Mark

doi:10.1002/(sici)1099-0488(19980930)36:13<2449::aid-polb19>3.0.co;2-3

Cited by 4 publications

(4 citation statements)

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“…It is unclear what the source of this large low-q scattering is; however, it must be caused by correlations over large length scales and probably has origins similar to the low-q scattering seen in rodlike or liquid crystalline polymers. 25…”

Section: ■ Discussionmentioning

confidence: 99%

“…Efforts were made to study these materials in the melt; however, low- q scattering prevented analysis even for P3AT samples which were isotropic melts. It is unclear what the source of this large low- q scattering is; however, it must be caused by correlations over large length scales and probably has origins similar to the low- q scattering seen in rodlike or liquid crystalline polymers …”

Section: Discussionmentioning

confidence: 99%

“…Studying the chain shape using small-angle neutron scattering for polythiophenes in the melt, as well as other rodlike or conjugated polymer systems, has been difficult because these polymers suffer from a large amount of low-q scattering caused by long-range correlations which overwhelms single chain scattering. 25 Previous studies have shown that there is a wide range of measured and predicted persistence lengths for P3ATs. This may be caused by effects from regioregularity, synthetic defects, side chains, and experimental difficulties measuring the persistence length.…”

Section: ■ Introductionmentioning

confidence: 99%

“…It is also important to note that P3ATs have strong intermolecular interactions which can cause polymer chain aggregation, even at low concentrations, which can make it difficult to extract single chain statistics. Studying the chain shape using small-angle neutron scattering for polythiophenes in the melt, as well as other rodlike or conjugated polymer systems, has been difficult because these polymers suffer from a large amount of low- q scattering caused by long-range correlations which overwhelms single chain scattering …”

Section: Introductionmentioning

confidence: 99%

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Polymer Chain Shape of Poly(3-alkylthiophenes) in Solution Using Small-Angle Neutron Scattering

et al. 2013

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The chain shape of polymers affects many aspects of their behavior and is governed by their intramolecular interactions. Delocalization of electrons along the backbone of conjugated polymers has been shown to lead to increased chain rigidity by encouraging a planar conformation. Poly(3-hexylthiophene) and other poly(3-alkylthiophenes) (P3ATs) are interesting for organic electronics applications, and it is clear that a hierarchy of structural features in these polymers controls charge transport. While other conjugated polymers are very rigid, the molecular structure of P3AT allows for two different planar conformations and a significant degree of torsion at room temperature. It is unclear, however, how their chain shape depends on variables such as side chain chemistry or regioregularity, both of which are key aspects in the molecular design of organic electronics. Small-angle neutron scattering from dilute polymer solutions indicates that the chains adopt a random coil geometry with a semiflexible backbone. The measured persistence length is shorter than the estimated conjugation length due to the two planar conformations that preserve conjugation but not backbone correlations. The persistence length of regioregular P3HT has been measured to be 3 nm at room temperature and decreases at higher temperatures. Changes in the regioregularity, side chain chemistry, or synthetic defects decrease the persistence length by 60–70%.

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Section: ■ Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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