title: Tunable solubility parameter of poly(3-hexyl thiophene) with hydrophobic side-chains to achieve rubbery conjugated films.
abstract: A highly π-conjugated nanofibrillar network of poly(3-hexyl thiophene) (P3HT) embedded in polydimethylsiloxane (PDMS) elastomer films on SiO2 dielectrics was facilely developed via solution-blending of an ultrasound-assisted dilute P3HT solution with a PDMS precursor followed by spin-casting and curing. In contrast, simple blending without ultrasonication against the dilute P3HT solution yielded large agglomerates in cast films owing to a great difference in solubility parameter (δ) values (P3HT = 9.5 cal(1/2) cm(-3/2), PDMS = 7.3 cal(1/2) cm(-3/2)). In the ultrasound-assisted 0.1 vol % P3HT solutions, the π-conjugated polymer could develop crystalline nanofibrils surrounded by nonpolar hexyl side chains with the same δ value as that of PDMS, yielding homogeneously dispersed 10 wt % loaded P3HT/PDMS blend films. Spun-cast P3HT/PDMS blend films could yield high electrical properties in organic field-effect transistor, including mobilities of up to 0.045 cm(2) V(-1) s(-1) and on/off current ratios of >5 × 10(5), as well as excellent environmental stability owing to the outer PDMS layer.
authors.affiliation: Department of Applied Organic Materials Engineering, Inha University , Incheon 402-751, Korea.
authors.forename: Seulyi
authors.initials: S
authors.lastname: Lee
authors.forename: Hyeonyeol
authors.initials: H
authors.lastname: Jeon
authors.forename: Mi
authors.initials: M
authors.lastname: Jang
authors.forename: Kyung-Youl
authors.initials: KY
authors.lastname: Baek
authors.forename: Hoichang
authors.initials: H
authors.lastname: Yang
keywords: ultrasonication, solubility parameter, miscibility, directed self-assembly, poly(3-hexyl thiophene), organic field-effect transistor