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  • Title: Highly ordered mesoporous carbonaceous frameworks from a template of a mixed amphiphilic triblock-copolymer system of PEO-PPO-PEO and reverse PPO-PEO-PPO.
    Author: Huang Y, Cai H, Yu T, Sun X, Tu B, Zhao D.
    Journal: Chem Asian J; 2007 Oct 01; 2(10):1282-9. PubMed ID: 17685375.
    Abstract:
    A series of highly ordered mesoporous carbonaceous frameworks with diverse symmetries have been successfully synthesized by using phenolic resols as a carbon precursor and mixed amphiphilic surfactants of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) and reverse PPO-PEO-PPO as templates by the strategy of evaporation-induced organic-organic self-assembly (EISA). The transformation of the ordered mesostructures from face-centered (Fd3m) to body-centered cubic (Im3m), then 2D hexagonal (P6mm), and eventually to cubic bicontinuous (Ia3d) symmetry has been achieved by simply adjusting the ratio of triblock copolymers to resol precursor and the relative content of PEO-PPO-PEO copolymer F127, as confirmed by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and nitrogen-sorption measurements. The blends of block copolymers can interact with resol precursors and tend to self-assemble into cross-linking micellar structures during the solvent-evaporation process, which provides a suitable template for the construction of mesostructures. The assembly force comes from the hydrogen-bonding interactions between organic mixed micelles and the resol-precursor matrix. The BET surface area for the mesoporous carbonaceous samples calcined at 600 degrees C under nitrogen atmosphere is around 600 m2 g(-1), and the pore size can be adjusted from 2.8 to 5.4 nm. An understanding of the organic-organic self-assembly behavior in the mixed amphiphilic surfactant system would pave the way for the synthesis of mesoporous materials with controllable structures.
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