Investigation of the surfactant type effect on characteristics and bioactivity of new mesoporous bioactive glass in the ternary system SiO2–CaO–P2O5: Structural, textural and reactivity studies

Abstract

In this study, a mesoporous bioactive glass 92S6 (92% SiO2, 6% CaO, and 2% P2O5), was successfully prepared using two different surfactants. The template was further removed by calcination to generate unorganized or well-ordered pores. The bioactive glass was characterized by wide angle X-ray diffraction (WAXRD) analysis, small angle X-ray diffraction (SAXRD) analysis, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). From the isotherm desorption branch, the surface area was determined using the Brunauer–Emmett–Teller (BET) method, while pore volume and pore size distribution were determined by the Barrett–Joyner–Halenda (BJH) method. The in vitro bioactivity tests were also conducted in simulated body fluid (SBF). Finally, the samples were analyzed to quantify the apatite formation ability when soaked in SBF solution. The evolutions of silicon (Si), phosphorus (P) and calcium (Ca) concentrations in SBF were evaluated by inductively coupled plasma optical emission spectrometry (ICP-OES).The SAXRD and TEM studies evidence the influence of the structure-directing agent (ionic surfactant CTAB or non-ionic P123) in the generation of unorganized or well ordered pores in the sol–gel synthesis of a bioactive glass in the ternary system SiO2–CaO–P2O5.As observed from small-angle XRD patterns and TEM images, the presence of non-ionic surfactant and subsequent calcination lead to the formation of highly ordered mesoporous glass.The better textural properties observed in the “ordered mesoporous glasses” compared to those of “non-ordered mesoporous glasses” lead to a faster in vitro bioactivity kinetics.