Influence of backbone structure on orientation of conjugated polymers in the dynamic casting of thin floating-films

• Published in: Thin solid films Vol. 619; pp. 125 - 130
• Main Authors: Pandey, Manish, Pandey, Shyam S., Nagamatsu, Shuichi, Hayase, Shuzi, Takashima, Wataru
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.11.2016
• Subjects: Conjugated polymer; Floating-film; Lyotropic liquid-crystalline phase; Molecular orientation; Polarized spectra; Floating-film; Conjugated polymer; Lyotropic liquid-crystalline phase; Molecular orientation; Polarized spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2016.11.015

Dynamic casting of conjugated polymer films on liquid-substrate is a unique method which provides thin floating-film and can be easily transferred on a desired substrate by stamping. The important feature in this procedure is associated with the formation of thin polymeric film during compression and solidification controlled by viscous drag of liquid substrate and solvent evaporation of the polymer, respectively. Lyotropic liquid-crystalline (LC) characteristics of conjugated polymer possibly assist to orient the polymer chain in one direction. It is found that this method produce highly oriented thin films (dichroic ratio >5) of thiophene-based conjugated polymers such as PBTTT-C14, PQT-C12 and non-regiocontrolled poly(3-hexylthiophene) NR-P3HT. On the other hand, weak orientation intensity in regioregular poly(3-hexylthiophene) RR-P3HT was found. The mechanism for this diverse orientation in thiophene-based conjugated polymers is discussed in correlation with the backbone chemical structure and lyotropic LC phase transition during the floating-film formation. •Orientation of different thiophene based conjugated polymers processed by dynamic-FTM.•Orientation intensity is related to the thiophene backbone structure.•PQT C-12 exhibited the highest optical anisotropy with dichroic Ratio of 6.4.•Correlation between the orientation and lyotropic LC behavior has been demonstrated.