Two new conjugated polymers (P1 and P2), containing a bithiophene donor unit coupled with either a triphenylene donor unit or an imide-functionalized triphenylene acceptor unit in the backbone, have been synthesized, structurally characterized, and comparatively studied by using ¹H NMR, FT-IR, gel permeation chromatography, differential scanning calorimetry, cyclic voltammetry, ultraviolet-visible absorption, and fluorescence spectroscopy. Both polymers are amorphous in nature and thermally stable up to 450°C. The inclusion of the imide functionalization in the triphenylene unit significantly lowered the lowest unoccupied molecular orbital energy level and thus the bandgap of the donor-acceptor polymer P2 over the donor-donor polymer P1. P1 and P2 show very different optical properties in hexane and other solvents. P1 shows a broad emission in hexane but vibronically structured emissions in other solvents; in contrast, P2 exhibits a vibronically resolved emission in hexane, while exhibiting redshifted, broad, and featureless emissions in other solvents. P1 takes a random coil conformation in good solvents like p-xylene, benzene, toluene, anisole, chloroform, THF, and o-dichlorobenzene, whereas in hexane, it may adopt a helical folding conformation. In the poor solvent DMSO, interchain aggregates dominate. P2, on the other hand, adopts a random coil conformation in hexane but possibly the helical folding conformation in other good solvents. The opposite conformations of the two polymers may be responsible for their opposite solvent-dependent fluorescence properties. By virtue of the very different fluorescence properties of these two polymers in nonpolar solvents such as hexane and in polar solvents, the potential of using the polymers to detect the trace amount of ethanol content that is added to gasoline has been revealed with high sensitivity.

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三亚苯基供体-供体和供体-受体共轭聚合物的合成及其光学性质的比较研究

通过¹ H NMR合成了两种新型共轭聚合物（P1和P2），其骨架中包含联噻吩供体单元，联苯亚苯基供体单元或酰亚胺官能化的联苯亚苯基受体单元，并进行了结构表征和比较研究， FT-IR，凝胶渗透色谱，差示扫描量热法，循环伏安法，紫外可见吸收法和荧光光谱法。两种聚合物本质上都是无定形的，并且在高达450°C的温度下具有热稳定性。在亚苯撑单元中包含酰亚胺官能化可显着降低最低的未占据分子轨道能级，从而降低供体-受体聚合物P2的带隙在施主-施主聚合物P1之上。P1和P2在己烷和其他溶剂中显示出非常不同的光学性质。P1在己烷中显示出较宽的发射，但在其他溶剂中显示了纤维结构的发射；相比之下，P2在己烷中呈现出经纤维分解的发射，而在其他溶剂中则呈现出红移，宽泛且无特征的发射。P1在对二甲苯，苯，甲苯，茴香醚，氯仿，THF和邻二氯苯等优质溶剂中呈无规卷曲构象，而在己烷中，P1可能呈螺旋折叠构象。在不良溶剂DMSO中，链间聚集体占主导地位。P2另一方面，在己烷中采用无规卷曲构象，但在其他良好溶剂中也可能采用螺旋折叠构象。两种聚合物的相反构象可能是其相反的溶剂依赖性荧光性质的原因。由于这两种聚合物在非极性溶剂（如己烷）和极性溶剂中的荧光性质非常不同，因此以高灵敏度显示了使用聚合物检测添加到汽油中的痕量乙醇含量的潜力。