| Abstract |
This work reports on the preparation and textural characterization of SiO2-CaO and SiO2-CaO-P2O5 sol-gel derived samples, with potential applications as scaffolds for bone regeneration, exhibiting a nano/macro bimodal pore size distribution, including pores of both similar to 100s of micrometres (mu m) and a few to 10s of nanometrcs (nm) in size. Interconnected macropores (similar to 10-200 mu m) have been obtained by polymerisation-induced phase separation along with the sol-gel transition, when a water soluble polymer (poly(ethylene oxide)) or a triblock copolymer (poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide)) was added to the sol-gel solution. On the other hand, the nanopore (similar to 5-40 nm) structure of such macroporous gel skeletons could be easily tailored by solvent exchange procedures. The morphology and texture of the gel-glassy scaffolds were observed by high resolution scanning electron microscopy, specific surface areas, pore volumes and pore size distributions have been determined by nitrogen adsorption techniques. The influence of factors that affect the porosity, such as glass composition, polymer added to the sol-gel solution, presence of pore expander additives and solvent exchange conditions has been assessed. |
