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 NTf2– 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.