National Deuteration Facility, Australian Nuclear Science & Technology Organisation , Lucas Heights, NSW Australia.
Biomacromolecules. 2014 Feb 10;15(2):644-9. doi: 10.1021/bm4017012. Epub 2014 Jan 8.
Infrared (IR) microspectroscopy has the capacity to determine the extent of phase separation in polymer blends. However, a major limitation in the use of this technique has been its reliance on overlapping peaks in the IR spectra to differentiate between polymers of similar chemical compositions in blends. The objective of this study was to evaluate the suitability of deuteration of one mixture component to separate infrared (IR) absorption bands and provide image contrast in phase separated materials. Deuteration of poly(3-hydroxyoctanoate) (PHO) was achieved via microbial biosynthesis using deuterated substrates, and the characteristic C-D stretching vibrations provided distinct signals completely separated from the C-H signals of protonated poly(3-hydroxybutyrate) (PHB). Phase separation was observed in 50:50 (% w/w) blends as domains up to 100 μm through the film cross sections, consistent with earlier reports of phase separation observed by scanning electron microscopy (SEM) of freeze-fractured protonated polymer blends. The presence of deuterated phases throughout the film suggests there is some miscibility at smaller length scales, which increased with increasing PHB content. These investigations indicate that biodeuteration combined with IR microspectroscopy represents a useful tool for mapping the phase behavior of polymer blends.
红外（IR）微光谱技术有能力确定聚合物共混物中相分离的程度。然而，该技术的一个主要限制是它依赖于 IR 光谱中的重叠峰来区分混合物中具有相似化学组成的聚合物。本研究的目的是评估氘化一种混合物成分以分离红外（IR）吸收带并在相分离材料中提供图像对比的适用性。通过使用氘代底物进行微生物生物合成，实现了聚（3-羟基辛酸酯）（PHO）的氘化，并且特征 C-D 伸缩振动提供了完全与质子化聚（3-羟基丁酸酯）（PHB）的 C-H 信号分离的独特信号。在 50:50（%重量/重量）共混物中观察到相分离，通过膜横截面达到高达 100μm 的域，与通过扫描电子显微镜（SEM）观察到的质子化聚合物共混物的相分离的早期报告一致。氘化相存在于整个薄膜中表明在较小的长度尺度上存在一定的混溶性，随着 PHB 含量的增加而增加。这些研究表明，生物氘化与 IR 微光谱学相结合是一种用于绘制聚合物共混物相行为的有用工具。
