Hydroxyapatite self-assembled dense film enhances proton conduction properties
2013-12-03
Date: 2013-12-03
Time: 3:45 PM
Venue: Zijinang Campus Environment and Resources College Conference Room B110
Speaker: Matthew Z. Yates
Speaker profile:Professor Matthew Z. Yates, Ph.D., Chemical Engineering, University of Texas Austin, TX, Los Alamos National Laboratory, Los Alamos, is currently the head of the Department of Chemical Engineering at the University of Rochester. He has hosted 13 research projects funded by NSF, NIH, etc. in the field of chemical separation, new energy materials, new medical materials, colloidal chemistry, crystallography and interface engineering technology, in Angew. Chem. Int. Edit., Adv. Mater., Adv. Funct. Mater., Chem. Mater. and other publications published more than 50 papers and authorized nine invention patents. He trained four Chinese doctoral students and had deep feelings for Chinese students. His first doctoral student came from Zhejiang University, so he was very close to our school. This is his first visit to China and I look forward to academic exchanges with you.
Department of Chemical EngineeringUniversity of Rochester
Hydroxyapatite (HA) is a crystalline calcium phosphate with the stoichiometric formula Ca5(PO4)3(OH) that has a disordered hexagonal crystal structure. The hydroxyl (OH) groups in HA form columns lining the crystallographic c-axis. At high temperatures (>200 °C), protons can move along the c-axis by a hopping mechanism through the hydroxyl columns. This talk describes a novel method to produce HA membranes and coatings in which the crystal domains are nearly perfectly aligned with the c-axis oriented normal to the coating surface, and the c-axis length passes through the entire membrane thickness. The unique aligned microstructure of the membrane provides proton conducting pathways through the membrane and eliminates interfaces that act as barriers to proton transport. As a result, proton conductivity is enhanced by orders of magnitude, opening up new potential applications of HA as a fuel cell membrane or electrochemical sensor. In addition, the electrical properties of the aligned membrane structure shows promise for enhancing bioactivity when HA is used as a coating on orthopedic or dental implants in order to enhance bone repair after implant surgery.