Nanostructure Manipulation Device for Transmission Electron Microscopy: Application to Titania Nanoparticle Chain Aggregates Yong J. Suh, 1 Sergey V. Prikhodko, 2 and Sheldon K. Friedlander 1 * 1 Department of Chemical Engineering, University of California, Los Angeles, CA 90095, USA 2 Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, USA Abstract: Experimental difficulties in studying nanostructures stem from their small size, which limits the use of traditional techniques for measuring their physical properties. We have developed a nanostructure manipu- lation device to apply tension to chain aggregates mounted in a transmission electron microscope. A 1-mm-long slit was cut in the center of a lead–tin alloy disc, measuring 3 mm in diameter and 200 mm in thickness. The disc was heated to about 1408C before it was pressed between two quartz slides. The disc was then thinned by mechanical dimpling and ion milling until holes developed around the slit. The edges of the slit were 0.2 to 3 mm in thickness while the gap between them was up to a few microns. This disc was bonded to the two plates of a cartridge. The slit could be widened or narrowed at controlled speeds of 0.5 to 300 nm/s. The system was tested using titania ~TiO 2 ! nanoparticle chain aggregates ~NCA! deposited across the slit. The ends of the NCA remained attached to the edges of the slit, which was widened at about 0.7 nm/s. In this way, the NCA was stretched up to 176% of its initial length before breaking. Key words: nanostructure, specimen support, cartridge, specimen holder, titania chain aggregates I NTRODUCTION Chain aggregates of nanoparticles are important industrial products serving as reinforcing fillers for rubber and other polymeric materials. Examples of the fillers are carbon black and fumed silica, which are manufactured in large quantities. Nanoparticle chain aggregates ~NCA! are also generated unintentionally at combustion sources such as diesel engines and in high-temperature processes involving metals such as welding and smelting. Experimental difficulties in studying nanostructures arise because of their small size, which limits the use of tradi- tional techniques for measuring their physical properties. In recent studies in our laboratory, NCA stretching was pro- duced by the movement of the edges of holes that formed in the Formvar ~polyvinyl formal! film on the transmission electron microscope ~TEM! grid ~Friedlander et al., 1998; Ogawa et al., 2000!. Figure 1a shows the initial shape of a titania NCA deposited on the TEM film. The holes resulted from weakening of the film by the electron beam. The application of tension “unraveled” some of the aggregate substructures present along the length of the chain ~Fig. 1b!; when the tension was relaxed, the substructures tended to reform while the NCA contracted rapidly ~Fig. 1c!. How- Received November 6, 2001; accepted March 12, 2002. *Corresponding author. E-mail: skf@seas.ucla.edu Microsc. Microanal. 8, 497–501, 2002 DOI: 10.1017/S1431927602010437 MicroscopyAND Microanalysis © MICROSCOPY SOCIETY OF AMERICA 2002