화학공학소재연구정보센터
Journal of Polymer Science Part B: Polymer Physics, Vol.57, No.17, 1105-1114, 2019
Collapse Transition-Assisted Crystallization in P3HT Solution
Understanding the multiple phase transitions such as collapse transition, phase separation, and crystallization in solutions is of fundamental importance to control the solution structure of conjugated polymers in device processing. Combining in situ synchrotron radiation small and wide-angle X-ray scattering, ultrasensitive differential scanning calorimetry, ultraviolet-visible absorption spectroscopy, and polarized optical microscopy, we investigate the order-disorder transitions in poly(3-hexylthiophene)/toluene solutions during cooling and heating processes. We demonstrate the occurrence of collapse transition of polymer chains from a random coil state to a lower dimensional network prior to the onset of crystallization during cooling in solution. This conformational preordering can lead to the formation of a lyotropic liquid crystalline phase, which is of great significance to the crystallization and ordering in polymer films, and further to promote its electric performance. It is examined that the mobility of films cast from chain-collapsed solutions can be one order of magnitude higher than that from isotropic solutions with random-coiled conformations. Thus, the conformational preordering in solutions is proposed to be a more efficient way than the postannealing of films to improve the electric performance of conjugated polymer films. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1105-1114