Influence of the polymer–polymer miscibility on the formation of mesoporous SiC(O) ceramics for highly efficient adsorption of organic dyes

In this paper, we use methyl-terminated polydimethylsiloxane (PDMS) as a pore-former and allylhydridopolycarbosilane (AHPCS) as a preceramic precursor to fabricate mesoporous SiC(O) ceramics by using liquid-liquid phase separation combined with cross-linking and emulsion processing. The influence of the polymer-polymer miscibility on the formation of mesoporous SiC(O) ceramics was investigated, with PDMS (350 cP) as porogen and AHPCS and polysiloxane (PSO) as preceramic precursors, respectively. Mesoporous SiC(O) with a specific surface area of 87.83 m 2g−1 and an average pore size of ca. 5 nm was produced by pyrolysis of a polymeric gel obtained from AHPCS/PDMS blends. In contrast, with PSO/PDMS blend as the starting material, mesopores were not formed in the final ceramics. In case of the AHPCS/PDMS blends, the polymer-to-ceramic transformation, the formation and the characteristic features of the mesopores were investigated by FT-IR, TGA, OM, SEM and N2 sorption isothermal analysis. The polymer-polymer miscibility between the preceramic polymer and the porogen polymer significantly influences the formation of the mesoporous ceramics. The final mesoporous SiC(O) ceramic obtained at 900 °C can withstand up to 1400 °C without significant change of the porosity. The resultant mesoporous SiC(O) shows highly efficient adsorption towards a model organic dye, namely Rhodamine B.