Mesocellular silica foam (MCF) was synthesized and modified by grafting polyacrylamide (PAAm) onto its surface. Grafting process was carried out by free radical polymerization using vinyltrimethoxysilane (VTMS) as coupling agent. The dependence of the final PAAm content with respect to monomer and initiator concentrations, reaction time, and temperature was evaluated. The PAAm contents in the hybrid material were determined by thermogravimetric analysis (TGA) and ranged from 15 to 64%. Diverse characterization techniques confirmed the grafting processes including small-angle X-ray scattering (SAXS), infrared spectroscopy, (FT-IR), nitrogen adsorption-desorption analyses, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According with SAXS and N-2 adsorption- desorption studies, the grafting of polymer may cause pore blockage of mesopores channels being more evident for MCF silica with high content of PAAm. (C) 2017 Elsevier B.V. All rights reserved.