ChBE Seminar Series: Matthew Yates
Tuesday, September 13, 2016
11:00 a.m.-12:00 p.m.
Room 2108, Chemical and Nuclear Engineering Building
Department of Chemical Engineering
University of Rochester
Electrical polarization and proton transport in hydroxyapatite
Hydroxyapatite (HA) is a hexagonal crystal phase of calcium phosphate that is found in the mineral component of teeth and bone tissue. Synthetic HA is most commonly known for its biocompatible and bioactive properties in orthopedic and dental applications. The stoichiometric formula of HA is Ca5(PO4)3(OH), but the crystal structure is stable under a range of non-stoichiometric compositions and with a variety of other elements partially substituted at the calcium, phosphate, and hydroxide positions of the crystal lattice. At elevated temperatures, it is known that protons are transported along the columns of hydroxide groups lining the crystallographic c-axis. It will be shown that proton transport is dramatically enhanced in HA thin films having crystal domains aligned with the c-axis normal to the substrate. It will also be shown that proton transport and chemical composition gradients can be used to impart quasi-permanent electrical polarization of the HA thin films. The unique electric polarization and proton transport properties potentially open new applications of HA in electrochemical devices, drug delivery, and orthopedic implants.
*Please Note: This event will be held via video conference.