BACKGROUND: MESOPOROUS NON-SILICEOUS OXIDES HAVE ATTRACTED GREAT INTEREST DUE TO THEIR UNIQUE PROPERTIES SUCH AS HIGH SURFACE AREAS, HIGHLY ORDERED CRYSTALLINE FRAMEWORK AND HIGH THERMAL STABILITY [1] AND THEIR POTENTIAL APPLICATIONS IN ENVIRONMENTAL CATALYSIS SUCH AS CO OXIDATION AND ELIMINATION OF ORGANIC POLLUTANTS AND OTHER APPLICATIONS IN BATTERIES, SENSORS, ENERGY CONVERSION AND STORAGE [2]...

IN THIS WORK A NOVEL METHOD IS PRESENTED FOR THE ELECTROCHEMICAL MODIFICATION OF MESOPOROUS SILICA AND PREPARATION OF ORDERED POROUS ELECTRODES. PREPARATION OF AMINE FUNCTIONALIZED THIN FILMS AT THE ELECTRODE SURFACE WAS ACHIEVED BY THE REPORTED METHODS AS ELECTRO ASSISTED SELF ASSEMBLY (EASA) UNDER POTENTIOSTATIC OR GALVANOSTATIC CONDITIONS. EASA WERE APPLIED ON GLASSY CARBON (GC) SUBSTRATES IN THE PRESENCE OF CETRIMONIUM BROMIDE (CTAB) AS STRUCTURE DIRECTING AGENT AND TETRAETHOXYSILANE AS SILICA PRECURSOR. [1] THE POROSITY OF FILM AND ITS MORPHOLOGY HAVE BEEN CHARACTERIZED BY TRANSMISSION ELECTRON MICROSCOPY (TEM). VOLTAMMETRIC BEHAVIOR OF SOME ELECTROACTIVE PROBES SUCH AS POTASSIUM HEXACYANOFERRATE (III), HEXAAMINE RUTHENIUM CHLORIDE AND CATECHOL HAVE BEEN STUDIED AT THE DESIRED MODIFIED ELECTRODE. NEXT ELECTROCHEMICAL OXIDATION OF A BUFFERIC SOLUTIONS OF CATECHOL HAVE BEEN CARRIED OUT ON MODIFIED ELECTRODE WITH AMINE FUNCTIONALIZED SILICA FILM IN ORDER TO FORMATION OF C-N BOND FORMATION BETWEEN CATECHOL AND AMINE GROUPS. [2] THE CATECHOL CONCENTRATION, PH OF SOLUTION, THE ELECTROCHEMICAL TECHNIQUES AND THE TIME OF FUNCTIONALIZATION HAVE BEEN OPTIMIZED FOR THE PREPARED FILMS. THE RESULTS SHOW THAT A POROUS AND ELECTROACTIVE ELECTRODE IS OBTAINED BY ELECTROCHEMICAL GENERATION OF REACTIVE O-QUINONE AT THE SURFACE OF ELECTRODE WITH WELL-ORGANIZED AND AMINE FUNCTIONALIZED MESOPOROUS SILICA THIN FILM.FINALLY THE ELECTROCHEMICAL BEHAVIOR OF THE PRESENTED ELECTROACTIVE POROUS ELECTRODES HAVE BEEN STUDIED BY CYCLIC AND HYDRODYNAMIC VOLTAMMETRY AND THE LOADING OF AMINOCATECHOLS IN STRUCTURE HAVE BEEN CONFIRMED BY THERMOGRAVIMETRIC AND ELEMENTAL ANALYSIS.

THIS STUDY HAS BEEN FOCUSED ON TWO TYPES OF MESOPOROUS SILICA NANOPARTICLES AS INSULIN DELIVERY SYSTEMS WHICH WERE SYNTHESIZED VIA SOL-GEL AND HYDROTHERMAL PROCESS. THE MORPHOLOGY AND STRUCTURE OF THE SILICA NANOPARTICLES WERE CHARACTERIZED BY DIFFERENT ANALYTICAL TECHNIQUES SUCH AS SCANNING ELECTRON MICROSCOPE (SEM), X-RAY DIFFRACTION ANALYSIS (XRD), FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR) AND BRUNAUER-EMMETT-TELLER (BET). THE RESULTS SHOWED THE AMORPHOUS STRUCTURE OF MCM-41 AND SBA-15 IN MESOPOROUS SILICA PARTICLES WHICH BOTH OF THEM HAVE A NARROW PORE SIZE DISTRIBUTION. ALSO, MORPHOLOGY OF MCM-41 WAS ROUND AND SBA-15 WAS NEARLY WHEAT-LIKE WITH ALMOST HOMOGENEOUS SIZE DISTRIBUTION.

SINCE THE DISCOVERY OF MCMS (MOBIL COMPOSITION OF MATTER) APPLICATION OF MESOPOROUS MATERIALS IN GENERAL AND MESOPOROUS SILICAS IN PARTICULAR, CONTINUES TO THRIVE. IN SPITE OF HIGH PROFILE OF THIS IMPORTANT CLASS OF COMPOUNDS, INCLUDING LARGE SURFACE AREA, UNIFORM PORE SIZE AND WELL DEFINED MORPHOLOGY, THEIR APPLICABILITY...