Predicting the Plateau Modulus from Molecular Parameters of Conjugated Polymers.
ACS Cent Sci
; 8(2): 268-274, 2022 Feb 23.
Article
in En
| MEDLINE
| ID: mdl-35233458
ABSTRACT
The relationship between Kuhn length l k , Kuhn monomer volume v 0, and plateau modulus G N 0, initially proposed by Graessley and Edwards for flexible polymers, and extended by Everaers, has a large gap in experimental data between the flexible and stiff regimes. This gap prevents the prediction of mechanical properties from the chain structure for any polymer in this region. Given the chain architecture, including a semiflexible backbone and side chains, conjugated polymers are an ideal class of material to study this crossover region. Using small angle neutron scattering, oscillatory shear rheology, and the freely rotating chain model, we have shown that 12 polymers with aromatic backbones populate a large part of this gap. We also have shown that a few of these polymers exhibit nematic ordering, which lowers G N 0. When fully isotropic, these polymers follow a relationship between l k , v 0, and G N 0, with a simple crossover proposed in terms of the number of Kuhn segments in an entanglement strand N e.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Type of study:
Prognostic_studies
/
Risk_factors_studies
Language:
En
Journal:
ACS Cent Sci
Year:
2022
Document type:
Article
Affiliation country:
United States