Biological Plywoods: Lessons from Nature's Fibrous Composites

Dr. Alejandro D. Rey, Department of Chemical Engineering, McGill University


06 December 2016 at 11:30

Location: BSB B136

 

This seminar presents recent theory and simulation results on the structure, self-assembly, and functionality of biological plywood materials1,2, an ubiquitous material organization found throughout Nature, including plant cell walls, exocuticles of insects, bone, and cornea. The key points of the talk are to demonstrate the principles used by Nature to develop stiff, strong, tough , multifunctional materials from simple rod-like filaments and to show a few examples based on biomimetic engineering on how to use the plywood architecture in optical and sensor devices.

The talk first describes how directed chiral self-assembly creates 3D fiber architectures with well defined pitches, a structural feature behind most of the structure-property relations. The presence of chiral fiber ordering is detected by the presence of "arc patterns" which is ubiquitous also in man-made macroscopic plywoods, but to extract precise fiber ordering requires geometric modeling. Here we show applications of the technique to a Costa Rican's beetle and to green algae. Finally we study the nano-wrinkling in surface layers of biological plywoods, which are responsible for optical functionalities and explain the diffraction patterns and color changes in tulip-like materials. A model for a bio-inspired color-based water sensor concludes the talk.

 

1. A.D. Rey, "Liquid Crystal Models of Biological Materials and Processes",

Soft Matter, 6-5, 3402-3429, 2010.

 

2. https://publishing.aip.org/publishing/journal-highlights/understanding-n...


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