title: Microcrystalline composite particles of carbon nanotubes and calcium carbonate.
abstract: Coprecipitation of urea-melt modified carbon nanotubes and calcium carbonate from an aqueous solution by two methods yielded microcrystalline composite particles. Powders obtained by colloidal crystallization from a supersaturated solution that were isolated and dried soon after precipitation were a mixture of raspberry-shaped and rhombohedral particles. These were shown by infrared and X-ray diffraction analyses to be mainly calcite. Particles that were kept wet for 1 day or longer before being isolated were typically entirely rhombohedral with edge lengths in the range of 5-30 microm. Scanning electron microscopy investigations revealed that the nanotubes were adsorbed on the particle surface and also incorporated into the interior matrix. Removal of the calcium carbonate component by treating the particles with acid yielded nanotube shells whose size and shape reflected those of the original particles.
authors.affiliation: Materials Science Laboratory, Stuttgart Technology Center, Sony Deutschland GmbH Hedelfingerstrasse 61, D-70327 Stuttgart, Germany. ford@sony.de
authors.forename: William E
authors.initials: WE
authors.lastname: Ford
authors.forename: Akio
authors.initials: A
authors.lastname: Yasuda
authors.forename: Jurina M
authors.initials: JM
authors.lastname: Wessels
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D011232:Chemical Precipitation; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010316:Particle Size; D014961:X-Ray Diffraction
chemical_list: D037742:Nanotubes, Carbon; D002119:Calcium Carbonate