Biomimetic Routes to Crystals with Superior Mechanical Properties
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
Nature is capable of remarkable control over mineral growth, producing biominerals such as bones, teeth and seashells which frequently display unusual morphologies and superior mechanical properties. Clearly this is achieved under mild conditions, and provides a unique inspiration for design and synthesis of new materials. Biominerals are typically composite materials, comprising a small amount of organic material in association with the mineral component, and it is this together with their structural organisation that results in the superior mechanical properties. Many biominerals are either amorphous or polycrystalline, and it is relatively easy to explain why these structures have good mechanical properties. Particularly remarkable, however, are biogenic single crystals which can also show considerable fracture resistance, behaviour which is generally considered to derive from organic macromolecules occluded within the crystals. This is in contrast to synthetic single crystals which typically fracture very easily due to the presence of low-energy fracture planes.This proposal will investigate incorporation of additives within crystals as a route to enhancing their mechanical properties, with the aim of producing a wide range of crystals with improved fracture resistance, and understanding how such additives can be incorporated within a single crystal. Although incorporation of organic additives is well-suited to biominerals which are formed and used under ambient conditions, it cannot be applied to advanced materials which are typically exposed to more extreme conditions during synthesis and use. This project offers a novel solution to this problem, and will for the first time incorporate chemically and thermally stable particles within single crystals to improve their mechanical properties. The mechanical properties of these composite crystals will be compared with both synthetic crystals incorporating organic additives and single crystal biominerals. The project will also provide the first systematic and quantitative study of this biogenic strategy.
Organisations
People |
ORCID iD |
Fiona Meldrum (Principal Investigator) |
Publications
Hetherington N
(2010)
Porous Single Crystals of Calcite from Colloidal Crystal Templates: ACC Is Not Required for Nanoscale Templating
in Advanced Functional Materials
Kim Y
(2011)
Biopolymer stabilized nanoparticles as co-catalysts for photocatalytic water oxidations
in Polymer Chemistry
Kim Y
(2010)
Bio-Inspired Synthesis and Mechanical Properties of Calcite-Polymer Particle Composites
in Advanced Materials
Kim Y
(2009)
Substrate-directed formation of calcium carbonate fibres
in J. Mater. Chem.
Kim YY
(2011)
An artificial biomineral formed by incorporation of copolymer micelles in calcite crystals.
in Nature materials
Meldrum FC
(2008)
Controlling mineral morphologies and structures in biological and synthetic systems.
in Chemical reviews
Stephens C
(2010)
Amorphous Calcium Carbonate is Stabilized in Confinement
in Advanced Functional Materials
Walsh D
(2011)
Synthesis of macroporous calcium carbonate/magnetite nanocomposites and their application in photocatalytic water splitting.
in Small (Weinheim an der Bergstrasse, Germany)
Description | Many biominerals exhibit superior mechanical properties. Particularly remarkable are biogenic single crystals which show considerable fracture resistance, behaviour which is generally considered to derive from organic macromolecules occluded within the crystals, giving them a composite character. Although this approach is well-suited to biominerals which are formed and used under ambient conditions, it cannot be applied to advanced materials which are typically exposed to more extreme conditions during synthesis and use. This project developed a novel solution to this problem and investigated the incorporation of particles within single crystals to improve their mechanical properties. The principal outcomes of the work were: (1) We developed strategies to successfully incorporate micron to nanosized particles within single crystals of calcite. (2) Detailed structural analyses of the composite crystals were performed using a wide range of analytical methods to determine the location of the particles within the single crystals, and their influence on the structure of the crystals. This enabled the macroscopic properties of the crystal to be related to the structure and strain present within the crystal lattice. (3) The mechanical properties of the composite crystals were measured using nanoindentation methods. Occlusion of larger particles (hundreds of nanometers) generated crystals that were less hard than pure calcite, but which showed greater fracture toughness. By comparison, occlusion of nanosized particles generated crystals that were harder than pure calcite. These crystals has properties comparable to calcite biominerals, such that they can be termed "artificial biominerals". |
Exploitation Route | Our work provides fundamental insight into the origins of the superior mechanical properties of biominerals, and therefore opens the door to generating synthetic materials with comparable properties. It also provides a novel methodology which can lead to single crystals with composite structures. |
Sectors | Agriculture Food and Drink Construction Energy Healthcare Manufacturing including Industrial Biotechology Other |
URL | http://www1.chem.leeds.ac.uk/FCM/ |
Description | This work was fundamental in nature and generated significant new insight into the origin of the superior mechanical properties of single crystal biominerals. We were also successful in translating these principles to synthetic crystals. |
Description | EPSRC |
Amount | £947,914 (GBP) |
Funding ID | EP/J018589/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2012 |
End | 09/2016 |
Description | EPSRC |
Amount | £321,751 (GBP) |
Funding ID | EP/G00868X/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 07/2009 |
End | 08/2012 |
Description | EPSRC |
Amount | £399,767 (GBP) |
Funding ID | EP/K006304/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 12/2012 |
End | 05/2015 |