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Bio‐Mimicked Silica Architectures Capture Geometry, Microstructure, and Mechanical Properties of Marine Diatoms

Luo, Shi and Greer, Julia R. (2018) Bio‐Mimicked Silica Architectures Capture Geometry, Microstructure, and Mechanical Properties of Marine Diatoms. Advanced Engineering Materials, 20 (9). Art. No. 1800301. ISSN 1438-1656. http://resolver.caltech.edu/CaltechAUTHORS:20180622-095714454

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Abstract

The authors create life‐sized synthetic replicas of marine diatom coscinodiscus sp frustules out of cyclohexyl polyhedral oligomeric silsesquioxanes (POSS). The authors demonstrate that these synthetic structures have biosilica‐like amorphous atomic‐level microstructure and mechanical attributes similar to those of a natural diatom. In situ beam bending and fracture experiments on micron‐sized excised sections of natural and synthetic diatoms reveal similarities in their mechanical properties: a Young's modulus of 20.2 ± 2.6 GPa and a fracture toughness of 0.78 ± 0.10 MPa m^(−1/2) for the synthetic materials; those of natural diatoms are 36.4 ± 8.3 GPa and 1.05 ± 0.08 MPa mm^(−1/2), respectively. In situ single edge notched beam (SENB) bending fracture experiments reveal that fracture behavior of the natural and synthetic specimens is virtually indistinguishable and is characterized by the same brittle failure and crack‐arresting behavior enabled by the double‐wall geometry. Their fracture toughness is comparable to that of fully dense silica, which suggests that the natural diatoms’ frustule maintains its mechanical resilience even at <50% of the weight attained through multi‐scale architecture. The demonstrated ability to fabricate a synthetic hard biomaterial that is virtually indistinguishable from its natural counterpart while capturing its complex architecture, microstructure, and mechanical properties provides a powerful platform for investigating the specific role of each geometrical feature at every relevant length scale in the often sophisticated, multi‐scale hierarchical construct of hard biomaterials, and provides a robust pathway for property optimization.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1002/adem.201800301DOIArticle
ORCID:
AuthorORCID
Greer, Julia R.0000-0002-9675-1508
Additional Information:© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Publication History: Version of Record online: 12 June 2018. Manuscript revised: 09 May 2018. Manuscript received: 25 March 2018. Funding Information: Institute for Collaborative Biotechnologies. Grant Number: W911NF‐09‐0001; US Army Research Office; Caltech's Discovery Funds.
Funders:
Funding AgencyGrant Number
Army Research Office (ARO)W911NF-09-0001
CaltechUNSPECIFIED
Subject Keywords:diatom ; fracture toughness ; mechanical properties ; POSS
Record Number:CaltechAUTHORS:20180622-095714454
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180622-095714454
Official Citation:Luo, S. and Greer, J. R. (2018), Bio‐Mimicked Silica Architectures Capture Geometry, Microstructure, and Mechanical Properties of Marine Diatoms. Adv. Eng. Mater., 20: 1800301. doi:10.1002/adem.201800301
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87318
Collection:CaltechAUTHORS
Deposited By: Katherine Johnson
Deposited On:22 Jun 2018 17:24
Last Modified:24 Sep 2018 22:40

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