Bioactive glass-mesoporous silica coatings on Ti6Al4V through enameling and triblock-copolymer-templated sol-gel processing

The combination of thick glass coatings that can protect Ti6Al4V from corro sion in the body fluids, and mesoporous silica films able to readily induce the formation of apatite when immersed in a simulated body fluid (SBF), ha s been investigated in this work as a possible route towards more resistant and long-lasting implants. Glasses in the system Si-Ca-Mg-Na-K-P-O with th ermal expansion coefficients close to that of Ti6Al4V were prepared and use d to coat this alloy by an enameling technique. However, the glasses apt to coat Ti6A14V exhibited a very limited capacity to induce apatite formation in SBF. In order to enhance their bioactivity, a thin film of mesoporous s ilica was applied on the exterior of the specimens by spin coating a sol-ge l solution. When tested in SBF, these coatings induced apatite formation af ter 7 days. The mesoporosity of the silica film was created through a tribl ock-copolymer-templating process. The diameters of the mesochannels could b e adjusted by changing the size of the directing agent. A preferred alignme nt of the mesostructure was observed. The removal of the organic templates could be achieved through a photocalcination treatment, which, compared to conventional thermocalcination, offered several advantages. (C) 2001 John W iley & Sons, Inc.