Acquisition of an Electron Microscope (Materials Research)

将获得用于研究复杂流体和聚合物体系的透射电子显微镜。新的冷冻断裂技术将使用电子显微镜直接检测聚丙烯酰胺凝胶，聚二乙炔溶液的棒线圈转变和表面活性剂-油水微乳液。这些系统的快速冷冻可以保持微观结构，没有伪影。固化后的液体被压裂，并涂上一层铂和碳，以复制裂缝表面。然后用分子分辨率的电子显微镜检查这些复制品。复制品也可以用扫描隧道显微镜检查，以评估高分辨率的三维轮廓。单个聚合物链可以以前所未有的分辨率可视化，并且可以测量凝胶中间隙流体的分布。第一次，直接反馈外部扰动对凝胶结构的影响是可能的。由等体积的油和水经表面活性剂共溶而成的中程微乳的三维结构也可以用分子分辨率来考察。可以检测导电聚合物复合材料的溶液浇铸膜，以确定复合材料的性质和导电部分的形态。生物和其他非导电材料可以同时成像扫描隧道和透射电子显微镜。

A transmission electron microscope for use in investigations of complex fluid and polymer systems will be acquired. Novel freeze-fracture techniques used will directly examine polyacrylamide gels, rod-coil transitions of polydiacetylene solutions, and surfactant-oil-water microemulsions using electron microscopy. Rapid freezing of these systems can preserve the microstructure without artifact. The solidified fluid is fractured and coated with layers of platinum and carbon to replicate the fracture surfaces. These replicas are then examined in the electron microscope with molecular resolution. The replicas can also be examined with the scanning tunneling microscope to assess three dimensional contours with high resolu1tion. Individual polymer chains can be visualized with unprecedented resolution and the distribution of interstitial fluid in gels can be measured. For the first time, direct feedback about the influence of external perturbations on the gel structure is possible. The three dimensional structure of mid- range microemulsions consisting of equal volumes of oil and water cosolubilized by surfactant can also be examined with molecular resolution. Solution cast films of conducting polymer composites can be examined to determine the nature of the composite and the morphology of the conducting fraction. Biological and other non-conducting materials can be imaged simultaneously with scanning tunneling and transmission electron microscopy.