Creation and Characterization of Carbon Nanotube Foams and Related Materials Pulickel Ajayan & Ravi Kane, Rensselaer Polytechnic Institute, DMR The research created 2-D and 3-D foams from carbon nanotubes utilizing as-grown organized nanotube architectures and using capillary induced condensation, for example by using solvent evaporation or etching, to assemble foams. Colloidal silica templates were used to fabricate porous three-dimensional architectures of multiwalled carbon nanotubes. Nanotubes grown on monolayer and multilayered assemblies of colloidal silica micro-particles, using chemical vapor deposition (CVD), were assembled into 3-D foams after silica removal by etching. SEM images of a) monolayer of silica spheres, b) the “Buckled” nanotube-silica membrane obtained after CVD, c) multilayered template of silica spheres and d) nanotube foams obtained after CVD growth on template (shown in c) and subsequent silica removal. The mechanical stability and structural integrity of these foams have been studied. The properties of the foams under tension and compression as well as electrical properties are under investigation. The applications of such lightweight, chemically and mechanically stable nanotube foams with high surface area could range from scaffolds in tissue engineering to electrodes for energy storage devices. Kaur et al. “Design and Characterization of three-dimensional Carbon Nanotube Foams.” J. Phys. Chem. B, 110, (2006) a d c b

Broad Impact of Research: The research on carbon nanotube foams have benefited other research projects in the laboratory. The work on foams has resulted in the creation of fascinating new architectures, using new kinds of templates, leading to structures that could be used in biology, bio-medical engineering and chemical engineering. Basic mechanisms of capillarity induced collapse in nanostructures, highlighted in this work, could shed light on pattern formation during wet assembly of various groups of nanostructures. Interdisciplinary work and collaboration with groups working in biomedical engineering has been one of the key outcomes of the project. Undergraduate Participation: Undergraduate students, as part of the project, received excellent training in areas of synthesis, processing and characterization of nanotube materials. Two undergraduates, from Materials Science & Engineering and Chemistry departments (Nicholas Renna and Csaba Vajtai), participated in the project last year. Some results from the project have been introduced in the undergraduate class room, via the “Materials for Engineers” core course taught by one of the investigators. Outreach: International collaboration has been a key accomplishment. The graduate student (Sumanjeet Kaur) was involved in a joint research work with her Mexican counterpart, with additional suuport from the NSF International program with Mexico ( DMR Inter America Materials Collaboration), contributing to the project. The analysis of samples exchanged between Mexico and our laboratory, resulted in two areas related to the project; foam formation in dense arrays of nitrogen doped nanotubes and growth of organized patterns of nitrogen doped nanotubes on various templates. A collaborative publication is being finalized. Creation and Characterization of Carbon Nanotube Foams and Related Materials Pulickel Ajayan & Ravi Kane, Rensselaer Polytechnic Institute, DMR