Novel synthesis route of porous clay heterostructures via mixed surfactant template and their dielectric behavior

摘要

Porous clay heterostructures (PCHs) have been developed for a decade now especially for adsorbent and catalytic support applications because of their high specific surface area with uniform small pore size. PCHs have been prepared through the surfactant-directed assembly of organosilicate in the galleries of montmorillonite (MMT), generally, single surfactant was applied. Challenge of using mixed surfactant template derived PCH is proposed to obtain higher surface area aiming for dielectric application. In this study, BC-PCH synthesized from mixed CTAB and CTAC surfactant systems was named and compared with B-PCH and C-PCH that synthesized from CTAB and CTAC surfactant system, respectively. The results revealed that the structure of MMT changed after modification and calcination process, as confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD) analyses. Textural properties characterization showed that the BC-PCH samples exhibited higher specific surface area (S-BET) 644-738 m(2)/g than that of B-PCH and C-PCH sample and slightly smaller pore size because the size of micelles in solution system from mixed surfactant decreases, which was confirmed by Dynamic Light Scattering analysis (DLS). Field Emission Scanning Electron Microscopy analysis (FE-SEM) illustrated the rough surface structure of mesoporous BC-PCH samples. The dielectric properties were measured by using the Inductance-Capacitance-Resistance meter (LCR). The dielectric constant (at 10(3) Hz) increased from 9 and 10 of single CTAB and CTAC surfactant template B-PCH and C-PCH to 15-17 of mixed surfactant series BC-PCHs, almost two-fold was obtained. The improvements of dielectric constant in BC-PCH samples are achieved by the increasing of interfacial polarization. Considering these results, BC-PCH materials can be further applied as candidates for an attractive filler to enhance the dielectric properties of polymer nanocomposite.