We fabricated porous organogels of poly(methyl methacrylate) (PMMA) using nonsolvents as porogens. In contrast to the use of inorganic materials, surfactants, etc., as porogens, we used the nonsolvents for PMMA such as water, methanol, propanol, and cyclohexane. This offers the advantage of not having to extract the porogen after gel formation. The nonsolvent simply evaporates. We find that the pore size can be controlled by matching the solubility parameters of the solvent/nonsolvent mixtures and that of PMMA. Incorporation of CNT itself does not lead to porous morphology in this case, unless a nonsolvent is added. Introducing carbon nanotubes during the addition of nonsolvent for gelation enhances the elongation ratio of the PMMA gel. We show that the CNT forms a network around the pores. Infrared and Raman spectra show no specific interaction between the CNT and PMMA. Hence, the former simply acts as a reinforcing filler.
Composite particles, i.e. PMMA nanoparticles trapping one to a few nanotubes in their core, were prepared by a derivative process of the solvent shifting technique, also called the ''Ouzo effect''. Particles were converted by simple annealing into nanocomposite films, the thermal resistance of which was evidenced by microcalorimetry and thermogravimetry.Scheme 1 Principle of entrapping of CNTs by the Ouzo-effect driven nanoprecipitation technique.
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