Solution-Based Techniques for Biomimetics and Bioreplication - Engineered Biomimicry - page 353

CHAPTER
14

Solution-Based Techniques for
Biomim etics and Biorepl ication

Aditi S. Risbud a and Michael H. Bartl b,c
a Lawrence Berkeley National Laboratory,
MS 67R3110, Berkeley, CA 94720, USA
b Department of Chemistry, University of Utah,
Salt Lake City, UT 84112, USA
c HRL Laboratories, LLC, Sensors and Materials Laboratory,
Malibu, CA 90265, USA

Prospectus
Nature generates structurally complex architectures
with feature sizes covering several length scales under
rather simple environmental conditions and with lim-
ited resources. Today, researchers understand how
many of these structures look and behave, but, in many
instances, we still lack nature's ability to marry elegant
structures with complex functionality. By unraveling
the wonders of nature's design, scientists have devel-
oped biomimetic and biotemplated materials with
entirely new functions and behaviors. In particular,
solution-based methods provide simple, inexpensive
routes to generating bioreplicated structures. In this
chapter, we survey solution-based bioreplication meth-
ods and provide an example for generating three-
dimensional photonic crystal structures based on
colored weevil scales. This example illustrates how
structural engineering in biology can be replicated
using sol-gel chemistry and results in an entirely new
optical material with fascinating properties.

Photonic crystal, Polymer, Replica, Scaffold, Soft chem-
istry, Sol-gel, Solution-based synthesis, Structural color,
Structure engineering, Templating, Three-dimensional
structure, Weevil

14.1 INTRODUCTION

Millions of years before researchers engineered
bioinspired materials, biological systems were
using nanometer-scale architectures to produce
remarkable functionalities. Today, scientists
are mimicking biological systems to enable a
wide range of technologies. Advanced func-
tional materials such as superhydrophobic sur-
faces have been fabricated based on structures
designed by living creatures, such as the pristine
lotus leaf.
The lotus leaf has long been viewed as a
symbol of purity due to its self-cleaning
properties. Dewy rainwater drops roll off a
lotus leaf's surface, taking dirt with them.
However, this cleanliness is actually due to a

Keywords
Band gap, Band structure, Beetle, Bioinspiration,
Biomaterials, Bioreplication, Biotemplated, Butterfly,
Colloids, Electrochemistry, Functional materials,
Gecko, Lotus leaf, Nanoparticle, Optical properties,