Dhaval A. Doshi

Silicone-Containing Surfactants as Templates in the Synthesis of Mesostructured Silicates

Well defined amphiphilic block copolymers containing a polydimethyl siloxane (PDMS) and a poly(ethylene oxide) block (PEO) were synthesized by ring opening polymerization of hexamethylcyclotrisiloxane, followed by chain extension with a PEO block of a defined length. These amphiphilic molecules were used as templates in a solvent-evaporation driven synthesis approach to self-assembled mesostructured silica films. Thin films and powders were prepared, and the resulting material was characterized by X-ray diffraction, transmission electron microscopy, and 29Si and 13C solid state NMR. The behavior of the PEO-b-PDMS block copolymer during heat treatment up to 600°C was followed in detail by solid state NMR.

Time-resolved in situ grazing incidence small angle x-ray scattering experiment of evaporation induced self-assembly

Abstract A time-resolved in-situ grazing incidence small angle x-ray scattering (GISAXS) experiment combined to gravimetric measurements of the slow evaporation of a liquid film of CTAB surfactant molecules dissolved in a mixture of TEOS and ethanol is presented. The complete investigation of the film formation, starting from the very beginning when the film is still in a liquid state to its final dried state is reported.