Surface Modification of PTMS Particles with Organosilanes: TEOS-, VTMS-, and MTMS-Modified PTMS Particles

초록

Phenyltrimethoxysilane (PTMS) hollow particles were prepared in an aqueous solution by two-step process that separates hydrolysis and condensation with controlling the pH of the medium. PTMS monomers were mainly hydrolyzed in acidic condition and condensed to form particles in basic condition. The obtained particles have a peculiar feature as of solubility in organic solvents such as acetone, benzene, chloroform, etc. The surface modification of PTMS particles was performed in an alcoholic solution with tetraethyl orthosilicate (TEOS) and in an aqueous solution with other organoalkoxysilane monomers such as vinyltrimethoxysilane (VTMS) and methyltrimethoxysilane (MTMS). The surface-modified PTMS particles were prepared with the variation of silane monomer concentration, ammonium hydroxide concentration, reaction temperature, and reaction time. Among the obtained particles, VTMS- and MTMS-modified PTMS particles could be changed into channeled hollow particles with the treatment of acetone. The changes in size and morphology of resultant PTMS particles and surface-modified PTMS particles were determined by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composition of surface-modified particles was characterized with infrared spectroscopic analysis (IR), solid-state nuclear magnetic resonance spectroscopy (NMR), and thermogravimetric analysis (TGA). The changes in isoelectric point (IEP) of the modified particles were observed with zeta potential analyzer.