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Supercritical CO2 extraction of porogen phase: An alternative route to nanoporous dielectrics

Publication Type : Journal Article

Publisher : Cambridge University Press

Source : Journal of Materials Research, Cambridge University Press, Volume 19, Number 11, p.3224–3233 (2004)

Campus : Coimbatore

School : School of Engineering

Department : Electronics and Communication

Year : 2004

Abstract : We present a supercritical CO2 (SCCO2) process for the preparation of nanoporous organosilicate thin films for ultralow dielectric constant materials. The porous structure was generated by SCCO2 extraction of a sacrificial poly(propylene glycol) (PPG) from a nanohybrid film, where the nanoscopic domains of PPG porogen are entrapped within the crosslinked poly(methylsilsesquioxane) (PMSSQ) matrix. As a comparison, porous structures generated by both the usual thermal decomposition (at approximately 450 °C) and by a SCCO2 process for 25 and 55 wt% porogen loadings were evaluated. It is found that the SCCO2 process is effective in removing the porogen phase at relatively low temperatures (200 °C) through diffusion of the supercritical fluid into the phase-separated nanohybrids and selective extraction of the porogen phase. Pore morphologies generated from the two methods are compared from representative three-dimensional (3D) images built from small-angle x-ray scattering (SAXS) data.

Cite this Research Publication : J. A. Lubguban, Gangopadhyay, S., Lahlouh, B., Dr. T. Rajagopalan, Biswas, N., Sun, J., Huang, D. H., Simon, S. L., Mallikarjunan, A., Kim, H. - C., and al., et, “Supercritical CO2 extraction of porogen phase: An alternative route to nanoporous dielectrics”, Journal of Materials Research, vol. 19, pp. 3224–3233, 2004.

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