Hydroxyapatite Thin Films with Giant Electrical Polarization

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• 作者：Cong Fu ; Keith Savino ; Paul Gabrys ; Aibin Zeng ; Baohong Guan ; Diana Olvera ; Chenggong Wang ; Boao Song ; Hani Awad ; Yongli Gao ; Matthew Z. Yates
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：February 24, 2015
• 年：2015
• 卷：27
• 期：4
• 页码：1164-1171
• 全文大小：412K
• ISSN：1520-5002

文摘

It is demonstrated that hydroxyapatite, a type of calcium phosphate commonly found in bone tissue, retains surprisingly large stored charge when synthesized electrochemically from aqueous solution. Thin films of hydroxyapatite formed on titanium and stainless steel electrodes were found to display giant polarization with quasi-permanent stored charge in excess of 70鈥?00 microcoulombs per square centimeter. The polarization of the hydroxyapatite film develops during synthesis as a result of field-induced changes in concentration of ionic reactants in the electrical double layer near the electrode surface. This novel mechanism of polarization during synthesis provides much larger stored charge than what is possible by postsynthesis poling of ferroelectric or electret materials. The polarized hydroxyapatite films on titanium are shown through in vitro experiments to hold promise in stimulating bone growth and may enable new applications in ion exchange separations, drug delivery, or energy storage.