Fanta Gada Muleta, Jarka Pawel, Szeluga Urszula, Tański Tomasz, Kim Jung Yong
Institute of Engineering Materials and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, 44-100 Gliwice, Poland.
School of Materials Science and Engineering, Jimma Institute of Technology, Jimma University, Post Office Box 378 Jimma, Ethiopia.
Polymers (Basel). 2020 Jul 31;12(8):1726. doi: 10.3390/polym12081726.
We report the phase behavior of amorphous/semicrystalline conjugated polymer blends composed of low bandgap poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']dithiophene) --4,7(2,1,3-benzothiadiazole)] (PCPDTBT) and poly{(,'-bis(2-octyldodecyl)naphthalene -1,4,5,8-bis(dicarboximide)-2,6-diyl)--5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)). As usual in polymer blends, these two polymers are immiscible because Δ ≈ 0 and Δ > 0, leading to Δ > 0, in which Δ, Δ, and Δ are the entropy, enthalpy, and Gibbs free energy of mixing, respectively. Specifically, the Flory-Huggins interaction parameter () for the PCPDTBT /P(NDI2OD-T2) blend was estimated to be 1.26 at 298.15 K, indicating that the blend was immiscible. When thermally analyzed, the melting and crystallization point depression was observed with increasing PCPDTBT amounts in the blends. In the same vein, the X-ray diffraction (XRD) patterns showed that the π-π interactions in P(NDI2OD-T2) lamellae were diminished if PCPDTBT was incorporated into the blends. Finally, the correlation of the solid-liquid phase transition and structural information for the blend system may provide insight for understanding other amorphous/semicrystalline conjugated polymers used as active layers in all-polymer solar cells, although the specific morphology of a film is largely affected by nonequilibrium kinetics.
我们报道了由低带隙聚[2,6-(4,4-双(2-乙基己基)-4H-环戊并[2,1-b;3,4-b']二噻吩)-4,7(2,1,3-苯并噻二唑)]（PCPDTBT）和聚{(2,2'-双(2-辛基十二烷基)萘-1,4,5,8-双(二甲酰亚胺)-2,6-二基)-5,5'-(2,2'-联噻吩)}（P(NDI2OD-T2)）组成的非晶态/半晶态共轭聚合物共混物的相行为。与聚合物共混物中的常见情况一样，这两种聚合物是不相容的，因为Δ≈0且Δ>0，导致Δ>0，其中Δ、Δ和Δ分别是混合熵、混合焓和混合吉布斯自由能。具体而言，PCPDTBT/P(NDI2OD-T2)共混物在298.15 K时的弗洛里-哈金斯相互作用参数（）估计为1.26，表明该共混物是不相容的。进行热分析时，随着共混物中PCPDTBT含量的增加，观察到熔点和结晶点降低。同样，X射线衍射（XRD）图谱表明，如果将PCPDTBT掺入共混物中，P(NDI2OD-T2)片晶中的π-π相互作用会减弱。最后，尽管薄膜的具体形态在很大程度上受非平衡动力学影响，但共混体系的固液相转变与结构信息之间的相关性可能为理解用作全聚合物太阳能电池活性层的其他非晶态/半晶态共轭聚合物提供思路。
