3. |
- Knaapila, Matti, et al.
(författare)
-
An effect of side chain length on the solution structure of poly(9,9-dialkylfluorene)s in toluene
- 2008
-
Ingår i: Polymer. - : Elsevier BV. - 0032-3861. ; 49:8, s. 2033-2038
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of side chain length of pi-conjugated poly(9,9-dialkylfluorene)s has been studied in semi-dilute (10 mg/mL) toluene solutions using small-angle neutron scattering (SANS) and H-1 and H-2 NMR spectroscopies. Under these conditions, SANS data indicate that poly(9,9-dinonylfluorene) and poly(9,9-dioctylfluorene) are dissolved down to the molecule level and appear as elongated one-dimensional chains (length >20-30 nm). In contrast, the shorter side chain polymers exhibit a self-association so that poly(9,9-diheptylfluorene) forms thin sheet-like (similar to 1 nm) and poly(9,9-dihexylfluorene) thin (similar to 1 nm) and thick sheet-like (>6 nm) aggregates. H-1 NMR data, together with the density functional theory (DFT) calculations, however, show that this occurs without changes in the conformation of the polymer backbone.
|
|