Title:

Polymer-reinforced Single Crystals of Calcite: Formation Mechanisms, Internal Structures, and Physical Properties

Speaker:

Dr. Lara A. Estroff

Affiliation:

Materials Science and Engineering, Cornell University

When:

Tuesday, April 27, 2010 at 3:00:00 PM   Add to Calendar

Where:

Love Building, Room 183

Host:

Nils Kroger
nils.kroger@chemistry.gatech.edu

Abstract

Single crystals are usually faceted solids with homogeneous compositions. Biogenic and synthetic calcite single crystals, however, have been found to incorporate macromolecules, spurring investigations of how large molecules are distributed within the crystals without significantly disrupting the crystalline lattice. In this work, we use ADF-STEM and electron tomography to characterize the internal structure of calcitic prisms from mollusks and synthetic calcite crystals, which were grown in an agarose hydrogel. The gel- grown calcite crystals, like the biogenic prisms, uniformly incorporate the organic matrix. These results suggest that physical entrapment of polymer aggregates is a viable mechanism by which macromolecules can become incorporated inside of inorganic single-crystals. We have also evaluated the parameters that control the incorporation of polymer networks during calcite crystal growth in agarose hydrogels. These results have led to design criteria for polymer-reinforced crystalline materials with unique structure- property relationships. I will also present preliminary results characterizing the mechanical properties of both the synthetic and biogenic single crystal composites. Insights provided by this work may help to elucidate the formation mechanism(s) and properties of biogenic single crystals with incorporated organic material.

Biography

Lara A. Estroff received her B.A. with honors from Swarthmore College (1997), with a major in Chemistry and a minor in Anthropology. Before beginning her graduate studies, she spent a year at the Weizmann Institute of Science in Rehovot, Israel as a visiting researcher in the labs of Profs Lia Addadi and Steve Weiner. During this time, she was introduced to the field of biomineralization and studied chemical approaches to archeological problems. In 2003, she received her Ph.D. in Chemistry from Yale University for work done in Prof. Andrew D. Hamilton's laboratory on the design and synthesis of bio-inspired organic superstructures to control the growth of inorganic crystals. After completing graduate school, she was an NIH-funded postdoctoral fellow in Prof. George M. Whiteside's laboratory at Harvard University (2003-2005). Since 2005, Dr. Estroff has been an assistant professor of Materials Science and Engineering at Cornell University. Her group focuses on bio-inspired materials synthesis, in particular, the study of crystal growth mechanisms in gels and their relationships to biomineralization. She has received several awards, including an NSF Early Faculty Career Award in 2009 and a J.D. Watson Young Investigator’s award from NYSTAR in 2006.