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DOE OSTI · 1903847

Improved Self-Assembly of P3HT with Pyrene-Functionalized Methacrylates

Pathiranage, Taniya N. S. K.·Ma, Ziyuan·Udamulle Gedara, Chinthaka M.·Pan, Xiangcheng·Lee, Youngmin·Gomez, Enrique D.·Biewer, Michael C.·Matyjaszewski, Krzysztof·Stefan, Mihaela C.
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Abstract

A block copolymer with discotic liquid crystalline behavior was synthesized using Grignard metathesis polymerization (GRIM) and initiators for continuous activator regeneration atom transfer radical polymerization (ICAR-ATRP). A novel discotic liquid crystalline mesogen, 6-(pyren-1-yloxy)hexyl methacrylate (PyMA), comprises a block that is attached to regioregular poly(3- hexylthiophene) (rr-P 3 HT) generated by GRIM and subjected to end-group modification. Due to the continuous regeneration of Cu + in the reaction mixture in ICAR-ATRP compared to conventional methods, the synthesis was successfully performed with less catalyst. The purity and yield of the final product are increased by eliminating rigorous post-synthesis purification. Stacked pyrene units have contributed to the enhanced long-range π-π interactions and aligning of the P 3 HT block as observed in thin-film X-ray diffraction (XRD). Furthermore, field-effect mobilities in the order of 10 -2 cm 2 V -1 s -1 in bottom-gate, top-contact organic field-effect transistors (OFETs) suggest an enhancement in charge transport due to the discotic electron-rich pyrene units that help mitigate the insulating effect of the methacrylate backbone. The formation of uniform microdomains of P 3 HT-bpoly(PyMA) observed with tapping mode atomic force microscopy (TMAFM) on the channel regions of OFETs indicates the unique packing of the block copolymer in comparison to pristine P 3 HT. Thermotropic properties of the novel discotic mesogen in the presence and absence of P3HT were observed with both the poly(3-hexylthiophene)-b-poly(6-(pyren-1-yloxy)hexyl methacrylate) (P3HT-b-poly(PyMA)) block copolymer and poly(6-(pyren-1-yloxy)hexyl methacrylate) (poly(PyMA)) homopolymer using polarized optical microscopy (POM) and differential scanning calorimetry (DSC).

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYaromatic compoundscopolymershydrocarbonsorganic compoundsorganic polymers

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Pathiranage, Taniya N. S. K., Ma, Ziyuan, Udamulle Gedara, Chinthaka M., Pan, Xiangcheng, Lee, Youngmin, Gomez, Enrique D., Biewer, Michael C., Matyjaszewski, Krzysztof, Stefan, Mihaela C.. 2021-10-08. Improved Self-Assembly of P3HT with Pyrene-Functionalized Methacrylates. https://doi.org/10.1021/acsomega.1c04176

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