Temperature‐rise fractionation of poly(3‐alkyl thiophenes)

This is the authors' abstract. We don't add key points for this paper.

In this article, we have investigated a temperature‐rise fractionation procedure for poly(3‐hexyl thophene) (P3HT) and poly(3‐octyl thophene) (P3OT) that provides well‐defined molecular weight (MW) fractions with improved molecular weight distributions (MWD) when compared with Soxhlet extraction. This process involves dispersing the material over C18‐boned silica stationary phase in a jacketed column and using incremental rises in column temperature ( T col ) to gradually improve solvent quality and selectively dissolve higher molecular weight samples with a narrow polydispersity (PDI). Fractionation of P3HT with Δ T col = 5 °C in methylene chloride (MC) yielded 7 fractions ranging from M p of 20 to 53 kg/mol with an average PDI of 1.80 compared with a mother sample of 3.10. Predominant recovery of P3HT was acquired for fractions with T col > 20 °C (30 wt %). Subsequent separation of P3OT in methylene chloride, with a reduced Δ T col of 3 °C per fraction, due to increased solubility from the longer alkyl chain, generated 8 fractions with a weight range of M n = 22 to 57 kg/mol with an mean PDI of 1.23 with the mother sample having PDI = 2.34, demonstrating the tunability of this method.