Paper Number
PO94 

Session
Poster Session

Title
Regio regularity effects on chain mobility and entanglement for poly(3-hexylthiophene)

Presentation Date and Time
October 14, 2015 (Wednesday) 6:05

Track / Room
Poster Session / Atrium/Harborview

Authors (Click on name to view author profile)

1. Xie, Renxuan (Penn State University, Chemical Engineering)
2. Gomez, Enrique D. (Penn State University, Chemical Engineering)
3. Colby, Ralph H. (Penn State University, Chemical Engineering and Materials Science and Engineering)

Author and Affiliation Lines (in printed abstract book)
Renxuan Xie¹, Enrique D. Gomez¹, and Ralph H. Colby^2
1Chemical Engineering, Penn State University, University Park, PA 16802; ²Chemical Engineering and Materials Science and Engineering, Penn State University, University Park, PA 16802

Speaker / Presenter 
Xie, Renxuan

Text of Abstract
Poly(3-hexylthiophene-2,5-diyl) (P3HT) is a conjugated polymer that can serve as the active layer in a variety of electronic devices, such as solar cells and thin-film transistors. However, fundamental properties of P3HT, including the glass transition temperature (Tg) and the entanglement molecular weight (Me), are still in dispute. These parameters play a central role in the microstructures of P3HT, such as intercrystalline connectivity and tie chains, which are believed to ultimately influence bulk electrical charge transport. In addition, P3HT can serve as an example to verify recently proposed scaling relationships for semiflexible polymers. A wide range of molecular weights of both regiorandom (RRa) and regioregular (RRe) P3HT have been studied using oscillatory and steady shear rheology. Coupled with the molecular weight distribution from GPC, Me was extracted by fitting the linear viscoelastic data of multiple molecular weight samples using BoB software. Furthermore, by using low-temperature oscillatory shear, two Tgs for both RRe and RRa P3HT were identified, which correspond to the segmental backbone motion and the side chain glass transition at lower temperature. RRe P3HT has a significantly larger Me than RRa P3HT, which might originate from the difference in side chain packing evidenced by their different lower Tg values. Thus, further investigation on their packing lengths through dilute solution light scattering will be crucial to understand entanglement in these semiflexible polymers.