The award will support the investigation of metal electrodeposition mechanisms on carbon nanofiber surfaces so that multi-functionalized materials with desired physico-chemical properties can be produced and evaluated for large scale engineering applications. Carbon nanofibers have comparable sizes and unique properties as multiwall carbon nanotubes but are available in large quantity with a competitive cost. Incorporating metallic coatings or particles onto the nanofiber surface can further improve its electric/thermal conductivity, magnetic field response, electromagnetic wave absorption, and catalytic activity. After being assembled into a paper sheet form, the carbon nanofibers can be reproducibly handled and used as electrodeposition electrodes. Electrodeposition provides an effective approach to introduce surface functionalization. Yet the metal nucleation, growth and bonding on these carbon nanomaterials remain largely unknown. This research will fill this critical gap by exploring the relationship between the synthesis parameters and the coating morphology and microstructures. The research can lead to the cost-effective handling and functionalizing carbon materials for their assembly into specific architectures in a reproducible fashion. This can help utilizaion of carbon nanofiber structures in applications such as lightning strike prevention, reinforced composites, electromagnetic shielding materials, static discharge, vibration/acoustic dampers, catalyst substrates, supercapacitors and bio/chemical sensors development. The broader impact on society will also be accomplished through education outreach efforts to show the opportunities and rewards of a career in science and engineering. In addition to support undergraduate and graduate research and modernize materials engineering curriculum, special emphasis will be placed on high school teacher and student education and training.
The award supported four year research on developing effective carbon nanomaterials handling techniques and modifying carbon nanofiber surface by electrodeposition of metallic coating for multi-functionalization and thus lead to large scale engineering applications. This project directly or partially supported and graduated 2 Phd students, 2 MS students, 4 undergraduate (through RET and research projects). Project led to 5 journal publications and three conference proceedings. One provisional US patent has been submitted and one is under development. The project lead to a collaborative research project with GE Oil and Gas and a three year grant (2011-2013, $195,000) was awarded. This award supported collaborative research efforts with the Advanced Photon Source (APS) at the Argonne National Laboratory to develop in situ synchrotron micro-diffraction and florescent technique to study metal nucleation and growth during electrochemical process. Traditionally, due to the existence of multiple phases and complicated transport and reaction process, there are few real time high resolution electrochemistry characterization techniques. Our study successfully demonstrated the use of synchrotron x-ray to characterize the structural and chemical properties of nanoscale metal deposits on the carbon surface. Control of the metal nucleation, growth mode, morphology and stability of Ni, Cu, Fe and Zn-Ni alloy during electrochemical synthesis have been realized. Build up on our 2-inch diameter carbon nanofiber papers synthesis capability, we successfully fabricate CNF nanopapers with diameters upto 8 inches. By incorporating these CNF papers into PDMS, we have fabricated nanocomposites with much improveed mechanical strength and thermal conductance, more importantly, significant electromechanial effects and dynamic damping characteristics have been observed. Application of these nanocomposites in bio-sensing, EMI shield and vibration/noise reduction applications are under development. In addition, based on the research supported by this award, we developed collaboration with GE Oil and Gas in exploring a liquid phasing mixing technique manufacturing carbon nanofiber reinforced HNBR nanocomposites for sealing applications. Compared to traditional industry manufacturing of HNBR compounds using mechanical mixing techniques, the solution based treatment improves CNF dispersion with concentrations upto 30phr. Initial mechanical tensile tests show much high compositie elastic modulus than conventional samples with same amount of carbon black and silica addtions. For broad education and outreach, we developed collaboration with Houston Harmony Science Academy (85% minority students), we developed long term collaboration to support high school teacher and student education and research activities. One Black and one Hispanic high school student team working on "Active functionalized carbon nanofiber demonstrator" has won the Special award from the 51th Houston Science and Engineering Fair (March 12-14, 2009). PI also volunteered to give one hour lecture on nanotechnology related to current project to freshman ME students every semester in the Introduction to Mechanical Engineering course (enrollment over 100). Starting from 2012, PI serve as the faculty advisor for the UH ASME student chapter and helping members to develop research/development and outreach activities.
