| 查看: 303 | 回复: 2 | |||
| 当前主题已经存档。 | |||
[交流]
美化学家发现金纳米棒自发地将自己组装成一种环状超结构
|
|||
|
Transmission electron microscopy (TEM) image of a circular superstructure of hybrid nanorods templated by a water microdroplet (Credit: Bishnu Khanal: Rice University)Ads by Google Advertise on this site Science Daily — Rice University chemists have discovered that tiny building blocks known as gold nanorods spontaneously assemble themselves into ring-like superstructures. This finding, which will be published the chemistry journal Angewandte Chemie, could potentially lead to the development of novel nanodevices like highly sensitive optical sensors, superlenses, and even invisible objects for use in the military. “Finding new ways to assemble nano-objects into superstructures is an important task because at the nanoscale, the properties of those objects depend on the arrangement of individual building blocks,” said principal investigator Eugene Zubarev, the Norman Hackerman-Welch Young Investigator and assistant professor of chemistry at Rice. Although ring-like assemblies have been observed in spherical nanoparticles and other symmetrical molecules, until now such structures had not been documented with rod-shaped nanostructures. Like many nanoscale objects, gold nanorods are several billionths of a meter, or 1,000 times smaller than a human hair. Zubarev used hybrid nanorods for this research because attached to their surface are thousands of polymer molecules, which are flexible chainlike structures. The central core of the nanorods is an inorganic crystal, but the polymers attached to the outside are organic species. The combination of the inorganic and organic features resulted in a hybrid structure that proved to be critical to the study. Working with Rice graduate student Bishnu Khanal, Zubarev placed the nanorods in a solution of organic solvent called chloroform. As the chloroform evaporated, its surface temperature dropped low enough to cause condensation of water droplets from the air, much like how dew forms. As thousands and thousands of microdroplets of water formed on the surface of the liquid chloroform, the nanorods that had been suspended in the solution started to press up against the round droplets and form rings around them. The polymer coating prevented the rods from being absorbed into the droplets because it is insoluble in water. After the droplets evaporated, the nanorods remained in their ring formation. “When nanorods are organized into a ring, significant changes in their optical and electromagnetic properties occur,” Zubarev said. “These can have technological applications in the area of metamaterials, which have enormous potential in opto-electronics, communications and military applications.” Zubarev said thousands of well-defined rings can be produced in a matter of seconds using the approach from his study. “This method is surprisingly simple and can be used for organizing nanocrystals of various shapes, size and chemical composition into circular arrays.” The research was funded by the National Science Foundation and the Welch Foundation. 来源:http://www.sciencedaily.com/releases/2007/03/070310145606.htm [ Last edited by luo.henry on 2008-4-11 at 13:55 ] |
回复此楼» 猜你喜欢
土木水利调剂，速码！错过等一年！
已经有0人回复
-
东北石油大学土木工程、土木水利专业招收调剂
已经有0人回复
-
建筑环境与结构工程论文润色/翻译怎么收费?
已经有193人回复
-
土木水利调剂
已经有0人回复
-
293 调剂
已经有1人回复
-
西京学院土木水利研究生调剂
已经有0人回复
-
招收调剂研究生——西京 土木水利
已经有0人回复
-
293求调剂
已经有2人回复
-
293求调剂
已经有6人回复
-
西京学院-结构工程-2026研究生调剂
已经有0人回复
-
南通大学-交通与土木工程学院 招调剂学生
已经有13人回复
» 本主题相关商家推荐: (我也要在这里推广)
