Multi-Scale Assembly of Polythiophene-Surfactant Supramolecular Complexes for Charge Transport Anisotropy

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• 作者：David Bilger ; Amrita Sarkar ; Cameron Danesh ; Manesh Gopinadhan ; Gregory Braggin ; Jose Figueroa ; Thanh Vy Pham ; Danielle Chun ; Yashas Rao ; Chinedum O. OsujiMorgan Stefik ; Shanju Zhang
• 刊名：Macromolecules
• 出版年：2017
• 出版时间：February 14, 2017
• 年：2017
• 卷：50
• 期：3
• 页码：1047-1055
• 全文大小：629K
• ISSN：1520-5835

文摘

Multiscale assembly of poly(3-alkylthiophene)s complexed with various alkyl-chain surfactant architectures has been investigated in dilute and concentrated solutions by means of ultraviolet–visible absorption and fluorescence spectroscopy, polarized optical microscopy, small-angle X-ray scattering, and four-point probe conductivity measurements. Supramolecular complexation occurs via ionic interactions between poly(3-alkylthiophene)s electrolytes and ionic surfactants. In dilute solutions, the supramolecular complex undergoes a coil-to-rod conformational transition as evidenced by a time-dependent chromism. Spectroscopic studies on transition kinetics reveal an inverse first-order rate law. While surfactant architectures significantly affect the persistence length of the complexes, the inverse first-order rate law is maintained. When concentrated above a critical value, the supramolecular complex exhibits an isotropic-to-liquid crystalline transition yielding hexagonally ordered microstructures. The liquid crystalline phase boundaries are largely dependent on polymer and surfactant architectures. The correlations between the intrinsic rigidity of conjugated polymers, optoelectronic properties, and liquid crystalline formation are presented. The dried films made from the sheared liquid crystalline solutions inherit liquid crystalline monodomains and display four times faster charge transport along the backbone alignment direction than the perpendicular direction.