Made to order

日期:2017-11-18 04:16:50 作者:阮光 阅读:

DESIGNER polymer chains that can be shortened to order have been made by researchers in the Netherlands. In time they hope to be able to shorten or lengthen polymers at will, possibly leading to products such as reversible glue. Conventional polymers consist of hundreds or thousands of molecules linked by covalent bonds to form long chains. Last year, Rint Sijbesma and his colleagues at Eindhoven University of Technology produced a polymer in which the links are weak hydrogen bonds. Now the team has found that they can disrupt the chains by adding “stopper” molecules. When irradiated with ultraviolet light, these step in for some of the molecules in the chain and force it to end, decreasing the viscosity of the material (Chemical Communications, 1998, p 1847). Such a polymer could be used as a glue,