Liou Sz-Chian, Chen San-Yuan, Liu Dean-Mo
Department of Materials Science and Engineering, National Chiao-Tung University, 1001 Ta-hsueh Road, Hsinchu, Taiwan 300, ROC.
Biomaterials. 2003 Oct;24(22):3981-8. doi: 10.1016/s0142-9612(03)00303-x.
Calcium-deficient apatitic (cd-HA) crystals with core-shell nanostructure with needlelike shape, 5-10nm in diameter and 20-80nm in length, were prepared via an in situ formation in the presence of polyacrylic acid (PAA) under aqueous solution of different pH values, ranging from 9 to 11. Nanostructure of the resulting crystals showing a core-shell configuration with a thin layer of PAA shell of about 1nm thickness was investigated. Aspect ratio (AR) of the needlelike composite was found to depend on the concentration of the PAA and solution pH. At lower solution pH, crystal growth was inhibited, i.e., leading to a decreased AR, with increase of PAA concentration, while an increased AR was detected at higher solution pH, suggesting a preferential growth of the cd-HA nanocrystals. Mechanism of such preferential growth was tentatively proposed and is suggested to correct PAA adsorption along the long axis of the needlelike nanoparticles.
通过在不同pH值（9至11）的水溶液中，在聚丙烯酸（PAA）存在下原位形成，制备了具有核壳纳米结构的缺钙磷灰石（cd-HA）晶体，其呈针状，直径为5-10nm，长度为20-80nm。研究了所得晶体的纳米结构，其呈现出具有约1nm厚度的PAA壳薄层的核壳构型。发现针状复合材料的长径比（AR）取决于PAA的浓度和溶液pH值。在较低的溶液pH值下，晶体生长受到抑制，即随着PAA浓度的增加，长径比降低，而在较高的溶液pH值下检测到长径比增加，表明cd-HA纳米晶体优先生长。初步提出了这种优先生长的机制，并建议沿针状纳米颗粒的长轴校正PAA吸附。
