Self-Assembly of Ionizable “Clicked” P3HT-b-PMMA Copolymers: Ionic Bonding Group/Counterion Effects on Morphology
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- 作者：Eunkyung Ji ; Virginie Pellerin ; Laurent Rubatat ; Eric Grelet ; Antoine Bousquet ; Laurent Billon
- 刊名：Macromolecules
- 出版年：2017
- 出版时间：January 10, 2017
- 年：2017
- 卷：50
- 期：1
- 页码：235-243
- 全文大小：590K
- ISSN：1520-5835
文摘
A novel methodology used to overcome the predominance of π–π interactions on the organization of rod–coil copolymer is reported in this paper. We demonstrated changes in the self-assembly morphology of poly(3-hexylthiophene)-b-poly(methyl methacrylate) (P3HT-b-PMMA) block copolymer BCP, by introducing an ionic group to the linking unit between the two blocks. A neutral polymer precursor was synthesized from ethynyl-terminated P3HT and azido-terminated PMMA via Huisgen’s 1,3-dipolar cycloaddition. Then two 1,2,3-triazolium-based block copolymers with different counteranions were obtained by a quaternization of 1,2,3-triazole groups with methyl iodide, and subsequent anion exchange was observed with a fluorinated salt, bis(trifluoromethane) sulfonimide salt. Atomic force microscopy, modulated differential scanning calorimetry, and X-ray scattering were used to prove that the crystallization of the conjugated block is disrupted by the additional ionic interactions imposed to the system. The 1,2,3-triazolium-based BCP with iodide as the counterion exhibited highly organized well-defined fibrils, as the diblock phase segregation χ becomes predominant over the rod–rod interaction μ. When the more stable and larger NTf2p>– p> was used as counterion, P3HT phase was disrupted and no crystallization was observed. This methodology could be a useful strategy to open the range of nanomorphologies reachable with a semiconducting polymer for electronic or photovoltaic applications.