Fabrication of Mesoporous Hydroxycarbonate Apatite/Polyaniline Composite Coatings on Ti6Al4V Substrates

摘要:

采用电泳沉积法在Ti6Al4V基体上形成碳酸钙/聚苯胺复合涂层，然后经磷酸缓冲溶液37 ℃下浸泡处理得到介孔碳酸根型羟基磷灰石/聚苯胺复合涂层。无裂纹的碳酸钙/聚苯胺复合涂层通过溶解-沉积反应转化成具有片状结构的碳酸根型羟基磷灰石/聚苯胺复合涂层，介孔和大孔分别存在于片状磷灰石内部和之间。模拟体液浸泡实验表明，多孔结构可以提高涂层的体外磷灰石形成活性，类骨型磷灰石首先沉积在介孔上，然后随着浸泡时间的延长逐渐覆盖所有大孔。此外，碳酸根型羟基磷灰石/聚苯胺复合涂层的体外磷灰石形成活性与聚苯胺纳米线有关，聚苯胺上的官能团（H2PO4-）不仅可以提高局部过饱和度，而且可以促进类骨型磷灰石的形核和生长。

Abstract:

Hydroxycarbonate apatite/polyaniline composite coatings (HCp/PANI coatings) with mesoporous structure were fabricated by the electrophoretic deposition of calcium carbonate particles and polyaniline (PANI) nanofibers on Ti6Al4V substrates followed by treatment with phosphate buffer solutions (PBS) at 37 ○C. After soaking in PBS, the perfect crack-free CaCO3/PANI coatings are converted to HCp/PANI coatings with platelet-like structure via a dissolution-precipitation reaction. The mesopores and the macropores (or apertures) are formed within and among the platelets, respectively. Simulated body fluid (SBF) immersion tests reveal that the porous structure can improve the in vitro apatite forming ability of coatings. In SBF, the bone-like apatite nanocrystals are firstly deposited around the mesopores, and then fill the macropores with the increase of immersion time. Moreover, the superior in vitro apatite forming ability of HCp/PANI coatings is related to the PANI nanofibers. The functional groups () in PANI not only increase the local supersaturation, but also induce the heterogeneous nucleation and the growth of bone-like apatites.