Xu Shuyu, Bruce Chase D, Rabolt John F, Noda Isao
Department of Materials Science and Engineering, University of Delaware, Newark, DE, USA.
Danimer Scientific, Bainbridge, GA, USA.
Appl Spectrosc. 2019 Sep;73(9):1012-1018. doi: 10.1177/0003702819848501. Epub 2019 May 20.
Raman spectra of a series of binary solution mixtures, including chloroform (CHCl), ethanol (EtOH), and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), were analyzed using the two-dimensional correlation spectroscopic (2D-COS) technique in the low frequency region. Numerous asynchronous cross-peaks ubiquitously appeared in the concentration-dependent Raman spectra of these organic solvent mixtures. The result clearly demonstrated a deviation from ideal solution behavior, reflecting the presence of specific molecular interactions causing a subtle nonlinear spectral intensity response of Raman bands to the concentration changes. Furthermore, the combination of 2D-COS and low frequency Raman spectroscopy was extended to poly[(R)-3-hydroxybutyrate--(R)-3-hydroxyhexanoate] (PHBHx) copolymer solutions in CHCl-HFIP co-solvents. The results suggest the existence of hydrogen bonding interaction between the PHBHx and HFIP, which is consistent with the previous infrared spectroscopic study of PHBHx solutions.
使用二维相关光谱（2D-COS）技术在低频区域分析了一系列二元溶液混合物的拉曼光谱，这些混合物包括氯仿（CHCl）、乙醇（EtOH）和1,1,1,3,3,3-六氟-2-丙醇（HFIP）。在这些有机溶剂混合物的浓度依赖性拉曼光谱中普遍出现了大量异步交叉峰。结果清楚地表明偏离了理想溶液行为，反映出存在特定的分子相互作用，导致拉曼谱带对浓度变化产生微妙的非线性光谱强度响应。此外，将2D-COS和低频拉曼光谱的组合扩展到了在CHCl-HFIP共溶剂中的聚[（R）-3-羟基丁酸酯-（R）-3-羟基己酸酯]（PHBHx）共聚物溶液。结果表明PHBHx与HFIP之间存在氢键相互作用，这与之前对PHBHx溶液的红外光谱研究结果一致。
