PDF(Pubmed)
Abstract：
Investigation of chiroptical polymers in the solution phase is paramount for designing supramolecular architectures for photonic or biomedical devices. This work is devoted to the case study of poly(propylene oxide) (PPO) optical activity in several solvents: benzonitrile, carbon disulfide, chloroform, ethyl acetate, and p-dioxane. To attain information on the interactions in these systems, rheological testing was undertaken, showing distinct variations of the rheological parameters as a function of the solvent type. These aspects are also reflected in the refractive index dispersive behavior, from which linear and non-linear optical properties are extracted. To determine the circular birefringence and specific rotation of the PPO solutions, the alternative method of the channeled spectra was employed. The spectral data were correlated with the molecular modeling of the PPO structural unit in the selected solvents. Density functional theory (DFT) computational data indicated that the torsional potential energy-related to the O1-C2-C3-O4 dihedral angle from the polymer repeating unit-was hindered in solvation environments characterized by high polarity and the ability to interact via hydrogen bonding. This was in agreement with the optical characterization of the samples, which indicated a lower circular birefringence and specific rotation for the solutions of PPO in ethyl acetate and p-dioxane. Also, the shape of optical rotatory dispersion curves was slightly modified for PPO in these solvents compared with the other ones.
摘要：
研究溶液相中的手性聚合物对于设计光子或生物医学器件的超分子结构至关重要。这项工作致力于研究聚（环氧丙烷）（PPO）在几种溶剂中的光学活性：苄腈，二硫化碳,氯仿,乙酸乙酯,和p-二恶烷。为了获得这些系统中相互作用的信息，进行了流变测试，显示作为溶剂类型的函数的流变参数的不同变化。这些方面也反映在折射率色散行为，从中提取线性和非线性光学性质。为了确定PPO溶液的圆双折射和比旋度，采用了通道光谱的替代方法。光谱数据与所选溶剂中PPO结构单元的分子模型相关。密度泛函理论（DFT）计算数据表明，与聚合物重复单元的O1-C2-C3-O4二面角相关的扭转势能在具有高极性和通过氢键相互作用的能力的溶剂化环境中受到阻碍。这与样品的光学表征一致，这表明PPO在乙酸乙酯和对二恶烷中的溶液具有较低的圆形双折射和比旋度。此外，与其他溶剂相比，PPO在这些溶剂中的旋光色散曲线的形状略有变化。
