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SUMMARY:Bio-Inspired Growth of Crystals: Hydrogels and Self-Assembled Mono
 layers - Assistant Professor Lara Estroff
DTSTART:20070119T141500Z
DTEND:20070119T151500Z
UID:TALK6090@talks.cam.ac.uk
CONTACT:Dr Kalin Dragnevski
DESCRIPTION:The design of artificial models of biomineralization has resul
 ted in the union of inorganic materials research and supramolecular organi
 c chemistry.  To begin unraveling the biological mechanisms of mineralizat
 ion\, and\, in doing so\, create new types of materials\, there is interes
 t in the design of supramolecular\, organic assemblies to alter the growth
  of inorganic crystals. In this seminar\, I will describe the application 
 of a matrix composed of an agarose hydrogel on top of a carboxylate-termin
 ated self-assembled monolayer (SAM) to control the nucleation and growth o
 f calcite crystals. The design of this matrix is based upon examples from 
 biomineralization in which hydrogels are coupled with functionalized\, org
 anic surfaces to control\, simultaneously\, crystal morphology and orienta
 tion. In the synthetic system\, calcite crystals nucleate from the (012) p
 lane (the same plane that is observed in solution growth). The aspect rati
 o (length/width) of the crystals decreases from 2.1 ± 0.22 in solution to
  1.2 ± 0.04 in a 3 wt% agarose gel. One possible explanation for the chan
 ge in morphology is the occlusion of gel fibers inside of the crystals dur
 ing the growth process. Etching of the gel-grown crystals with distilled w
 ater reveals an interpenetrating network of gel fibers and crystalline mat
 erial. We are currently investigating the mechanism of occlusion and the s
 tructure and mechanical properties of the composite material. This work be
 gins to provide insight into why organisms use hydrogels to control the gr
 owth of crystals.
LOCATION:IRC in Superconductivity Seminar Room\, Cavendish Laboratory
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