Bio-Inspired Routes for Controlling the Structure and Properties of Materials: Reusing proven tricks on new materials.

Boaz Pokroy

The department of Materials Science and Engineering

Technion Israel Institute of Technology

In the course of biomineralization, organisms produce a large variety of functional biogenic crystals that exhibit fascinating mechanical, optical, magnetic and other characteristics. More specifically, when living organisms grow crystals they can effectively control polymorph selection as well as the crystal morphology, shape, and even atomic structure. Materials existing in nature have extraordinary and specific functions, yet the materials employed in nature are quite different from those engineers would select.

Engineering materials in many ways still lack various aspects found in biological materials, for example one faces the challenges of forming single crystals with intricate shapes and without facets, or one has to find ways to control the atomic structure of materials. Moreover, it is not easy to form such materials at ambient conditions as nature does. To address these challenges, we emulate specific strategies used by organisms in forming structural biogenic crystals, and apply these strategies biomimetically so as to form new structural materials with new properties and characteristics. This bio-inspired approach involves the adoption of several specific biological strategies. We believe that this procedure will open up new ways to control the structure and properties of smart materials.

Some of the bio-inspired strategies we successfully utilized and will be presented in this talk are:

(i) control the short-range order of amorphous materials, making it possible to predetermine the polymorph obtained when they transform from the amorphous to the succeeding crystalline phase;

(ii) control the morphology of single crystals of various functional materials so that they can have intricate and curved surfaces and yet maintain their single-crystal nature;

(iii) entrap organic molecules into single crystals of functional materials so as to tailor and manipulate their electronic structure.