A Raman Spectroscopy Study on Single-Wall Carbon Nanotube/ Polystyrene Nanocomposites: Mechanical Compression Transferred from the Polymer to Single-Wall Carbon Nanotubes

摘要

Single-wall carbon nanotube/polysryrene (SWCNT/PS) nanocomposites were prepared by solution coagulation. Characterization was performed using Raman and infrared spectroscopy to elucidate the interactions between the SWCNTs and PS inside the nanocomposites. It was found that the G~-, G~+, and G' SWCNT bands shifted to higher wavenumbers when incorporated into the nanocomposites. We determined that this upshift was induced exclusively by a mechanical compression transfer from PS to the SWCNTs. From the magnitude of the upshift, the mechanical compression transfer was estimated to be ～518 MPa. Interestingly, we found that the upshift of the radial breathing mode was dominated by two factors: a van der Waals effect due to separation of the SWCNTs and mechanical compression from the PS system. A comparison of the laser heating effects on pristine SWCNTs and on the nanocomposites showed that thermal expansion of the SWCNTs in the nanocomposites was suppressed by the mechanical comr of the SWCNTs in the nanocomposites was suppressed by the mechanical compression from the PS system. The combination of Raman and infrared spectroscopy enabled detailed characterization of the interactions occurring the nanocomposites, which cannot be achieved using other conventional methods.