Nanomaterials Galore

Excerpted from Nanotechnology For Dummies by Richard Booker and Earl Boysen

In This Chapter

Working with carbon atoms as building blocks
Kicking off nanotechnology with buckyballs
Changing the world around us with nanotubes
Energizing electronics with nanowires

Read the popular science journals out there and you’ll see a lot of ink slung about how things made with nanomaterials are going to be stronger, more sensitive, lighter in weight, or have more load capacity than regular old materials. Delve into the issue a bit more, and you find out that actually getting simple carbon atoms to do all this for us is rather a complex little story.

To understand how nanomaterials will be used, you need a clear look at not only how they are formed but also their various configurations. In this chapter, we look at nano building blocks, and how they’re currently being cajoled into enhancing all kinds of materials and products. Some of this work is still in the research phase; other work has graduated to the big bad world of real, existing consumer products and applications.

It All Starts with Carbon

Carbon atoms are all over the place. In fact, you can find them in millions of molecules. These molecules have a wide range of properties, meaning they pop up in every possible form — from gases such as propane to solids such as diamonds, the hardest material found in nature (and reportedly a girl’s best friend).

“Bond, carbon bond . . .”

In covalent bonding, the atoms that bond share two electrons, regardless of whether they’re shaken or stirred; this sharing of electrons is what holds the atoms together in a molecule. If the ability of each atom to attract all those negatively charged electrons (called electronegativity) is reasonably close (that is, if the difference in electronegativity is no more than 2), then they can form covalent bonds. Because the electronegativity of carbon atoms is 2.5 (roughly in the midrange), they can form strong, stable, covalent bonds with many other types of atoms with higher or lower values.

There are three significant reasons for the wide range of properties of materials containing carbon:

Carbon atoms can bond together with many types of atoms, using a process called covalent bonding (we discuss the details of covalent bonding later in this section). When carbon atoms bond with different types of atoms, they form molecules with properties that vary according to the atoms they’ve bonded with.

Each carbon atom can form these covalent bonds with four other atoms at a time. That’s more bonds than most other atoms can form. Each nitrogen atom (for example) can form only three covalent bonds, each oxygen atom can form only two covalent bonds, and so on. This four-bond capability allows carbon atoms to bond to other carbon atoms to make chains of atoms — and to bond with other kinds of atoms at various points along such chains. This wide range of potential combinations of atoms in a molecule allows for a correspondingly wide range of potential properties.
There’s no other element in the periodic table that bonds as strongly to itself and in as many ways as the carbon atom. Carbon atoms can bond together in short chains, in which case they may have the properties of a gas. They may bond together as long chains, which might give you a solid, like a plastic. Or, they can bond together in 2- or 3-dimensional lattices, which can make for some very hard materials, such as a diamond.

With capabilities like these, carbon atoms are a natural for use in nanomaterials (as you discover in the following sections).