Rationalizing the self-assembly of poly-(3-hexylthiophene) using solubility and solvatochromic parameters

Abstract

The assembly of poly(3-hextylthiophene) (P3HT) in solvent mixtures is studied using solubility and solvatochromic parameters. Correlations between the excitonic coupling of P3HT assemblies and the Kamlet–Taft (α, β, π*) and solvent scales reveal that lower excitonic coupling values are observed in binary mixtures characterized by low β values (0 < β ≤ 0.25) and low polarity (0.1 ≤ ≤ 0.3). Hansen solubility theory is revisited by evaluating the directionality of the solubility distance, Ra. Relationships between the excitonic coupling and the Δδh and Δδp vector components indicate that the polarity of the solvent (Δδp) and the specific solvent-solvent interactions reflected by the Δδh component direct the formation of well-ordered P3HT aggregates. The complementary results of the solubility and solvatochromic parameter analyses are in agreement with one another. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 841–850