Crystallization and Melting Behavior of Poly(3-butylthiophene), Poly(3-octylthiophene), and Poly(3-dodecylthiophene)

• Published in: Macromolecules Vol. 38; no. 2; pp. 409 - 415
• Main Authors: Causin, Valerio, Marega, Carla, Marigo, Antonio, Valentini, Luca, Kenny, Josè Maria
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 25.01.2005
• Subjects: Applied sciences; Crystallization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization; Substituent effect; Conducting polymers; Melt crystallization; Melting; Thiophene derivative polymer; Crystallization; Aromatic polymer; Kinetics; Experimental study; Isothermal crystallization
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma048159+

The crystallization and melting behavior of poly(3-butylthiophene) (P3BT), poly(3-octylthiophene) (P3OT), and poly(3-dodecylthiophene) (P3DDT) were studied. The equilibrium melting temperatures (T m 0) of these polymers were measured and resulted equal to 321, 230, and 175 °C for P3BT, P3OT, and P3DDT, respectively. The crystallization kinetics was evaluated by the Avrami equation:  it proceeds by heterogeneous nucleation with one-dimensional linear growth (n = 1.1−1.8). The effects of the length of the alkyl side chain and of the undercooling were investigated. Phase I, Phase II, and a nematic mesophase were detected in P3BT and P3DDT. In P3BT, Phase I was differentiable from the mesophase on the basis of wide-angle X-ray scattering (WAXS) patterns. This study gives insight, in particular, on the crystallization and melting behavior of P3BT, a polymer not yet well studied. WAXS, small-angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC) were employed as experimental techniques.