Fabrication of polymer-apatite composites by using a novel alternate soaking process

Recently, we developed a novel alternate soaking process for the purpose of the fabrication of polymer-apatite composites. Using this method, bone-lik e apatite could be formed on/in the hydrogel matrix in normal condition in vitro. This research work deals with the apatite formation by the alternate soaking process using model substrates, such as poly(vinyl alcohol) (PVA) hydrogels and poly(acrylic acid) -or polyacrylamide-grafted polyethylene (P AAc-or PAAm-graft-PE) films. Bone like apatite with low crystallinity was f ormed on these substrates. Apatite formation on/in PVA gels accelerated wit h an increase in the swelling ratio of the gels. The crystallinity of apati te that was formed on/in PVA gels could be controlled by changing the react ion temperatures. On the other hand, the amount of apatite on PAAm-graft-PE films increased with increasing grafting density of PAAm. Specific behavio r of apatite formation and morphology were observed on PAAc-graft-PE films. Apatite formation by this novel alternate soaking process on a polymer sub strate was accomplished about 100-fold faster than that by a biomimetic pro cess. It is expected that this novel alternate soaking process is useful fo r the industrial fabrication of polymer-apatite composites.