Orientational ordering within semiconducting polymer fibrils

Published

May 2, 2021

Author(s)

Subhrangsu Mukherjee, Eliot Gann, Masrur M. Nahid, Terry McAfee, Andrew Herzing, Dean DeLongchamp, Harald W. Ade

Abstract

Due to a general paucity of suitable characterization methods, the internal orientational ordering of polymer fibrils has rarely been measured despite its importance particularly for semi-conducting polymers. An emerging tool with sensitivity to bond orientation is polarized resonant soft X-ray scattering (P-RSoXS). Here, P-RSoXS reveals the molecular arrangement within fibrils (if type I or type II fibrils), the extent of orientation in the fibril crystal, and an explicit crystal-amorphous interphase. Neat films as well as binary blends with a fullerene derivative are characterized for three different polymers, that are prototypical materials widely used in organic electronics applications. Anisotropic P-RSoXS patterns reveal two different fibril types. Analysis of the q-dependence of the anisotropy from simulated and experimental scattering patterns reveal that neat polymer fibrillar systems likely comprise more than two phases, with the third phase in addition to crystal and amorphous likely being an interphase with distinct density and orientation. Intriguingly, the fibril type correlates to the H- or J-aggregation signature in ultraviolet-visible (UV–vis) spectroscopy, revealing insight into the fibril formation. Together, the results will open the door to develop more sophisticated structure-function relationships between chemical design, fibril type, formation pathways and kinetics, interfacial ordering, and eventually device functions.

Citation

Advanced Functional Materials

Pub Type

Journals

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DOI Link

Keywords

Resonant Soft X-ray scattering, scattering anisotropy, fibrils, chain alignment, aggregates, polymorphs

Citation

Mukherjee, S. , Gann, E. , Nahid, M. , McAfee, T. , Herzing, A. , DeLongchamp, D. and Ade, H. (2021), Orientational ordering within semiconducting polymer fibrils, Advanced Functional Materials, [online], https://doi.org/10.1002/adfm.202102522 (Accessed April 18, 2024)