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Title: Multifunctionality of chiton biomineralized armor with an integrated visual system

Nature provides a multitude of examples of multifunctional structural materials. There are often trade-offs in these materials because few of them are equally well suited for multiple tasks. One such example is the biomineralized armor of the chiton Acanthopleura granulata, which incorporates an integrated sensory system that includes hundreds of eyes with aragonite-based lens. Here, we used optical experiments to demonstrate directly, for the first time, that these microscopic, mineralized lenses are able to form images. Furthermore, our experiments revealed that the optical performance of these polycrystalline lenses is enhanced by the reduction of spherical aberration through the shape of the lens and that birefringence scattering is minimized by the use of relatively large, co-aligned grains (~10 μm as compared to ~1 μm in the non-eye regions). Additionally, we used multi-scale mechanical testing techniques to show that A. granulata’s lenses are an integral component of its biomineralized armor, but that both the intrinsic and overall mechanical properties of the lenses are compromised as compared to the primary solid regions of the armor plates. Our results demonstrate that as the size, complexity, and functionality of the integrated sensory elements increases, the local mechanical performance of the armor decreases. But, A. granulatamore » has evolved several strategies to compensate for its local mechanical vulnerabilities to form a multifunctional system with co-optimized overall optical and structural functions.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [3] ;  [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Harvard Univ., Cambridge, MA (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  3. Harvard Univ., Cambridge, MA (United States)
  4. Univ. of South Carolina, Columbia, SC (United States)
  5. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
OSTI Identifier:
1237591
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Science
Additional Journal Information:
Journal Volume: 350; Journal Issue: 6263; Journal ID: ISSN 0036-8075
Publisher:
AAAS
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); USDOE Office of Science - Office of Basic Energy Sciences
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE