Apatite coating on poly(acrylic acid) grafted poly(ethylene) films by using an alternate soaking process

摘要

Recently, we developed a novel alternate soaking process for apatite formation on/in organic 3-D matrix. This process is based on the widely-known wet process for hydroxyapatite preparation in which it is done by alternately soaking in CaCl_2/Tris-HCl and Na_2HPO_4 aqueous solutions. In the present study, we report apatite coating on poly(acrylic acid) grafted poly(ethylene) films (PAAc-PE) with various PAAc densities. The amount of apatite formed on PAAc-g-PE films increased with an increase in the grafting density of PAAc when the grafting densities of PAAc were up to 30 mu g/cm~2. Interestingly, the amount of apatite coated on PAAc-g-PE decreased when the grafting densities of PAAc were more than 30 mu g/cm~2. From SEM observation, porous apatite crystals were observed on PAAc-g-PE of 30 mu g/cm~2. On the other hand, plate-like apatite layer was found on PAAc-g-PE of more than 30 mu g/cm~2. These results suggest that an alternate soaking process can be applied on polymer substrates for apatite coating, and that apatite crystal growth can be controlled by changing the grafting densities of PAAc. We think that these results also indicate new considerations of biomineralization.