Imaging the volume transition in thermosensitive core-shell particles by cryo-transmission electron microscopy

被引:84
作者
Crassous, JJ
Ballauff, M
Drechsler, M
Schmidt, J
Talmon, Y
机构
[1] Univ Bayreuth, D-95440 Bayreuth, Germany
[2] Technion Israel Inst Technol, Dept Chem Engn, IL-32000 Haifa, Israel
关键词
D O I
10.1021/la053198f
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
We report a study of colloidal thermosensitive core-shell particles by cryo-transmission electron microscopy (cryo-TEM). The particles consist of a solid core of poly(styrene), onto which a network of cross-linked poly(N-isopropylacrylamide) (PNIPAM) is affixed. In water, the shell of these particles swells when the temperature is low. Raising the temperature above 32 degrees C leads to a marked shrinking of the shell. In this letter, we present the first study of these core-shell particles by cryo-TEM in situ, that is, in aqueous solution. We demonstrate that the core-shell particles are well-defined and exhibit a narrow size distribution. In particular, the PNIPAM shell is compact and has a defined outer surface of a slightly irregular shape. The micrographs show that there are density fluctuations within the network. Cryo-TEM of the system above and below the transition temperature furnishes information about the thermosensitive particles that had not been available through other methods employed in previous investigations.
引用
收藏
页码:2403 / 2406
页数:4
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