A

aerogel

A silicon-based foam composed mostly of air. Often called "frozen smoke" or "blue smoke," aerogels have extremely low thermal conductivity, which gives them extraordinary insulating properties. They are the lowest-density solids known on earth.

aerosol

A suspension of fine particles (0.01-10 microns) of a solid or liquid in a gas.

aggregation

A collection of individual units or particles gathered together into a mass or body.

alkali metals

A group of soft, very reactive elements that includes lithium, sodium, and potassium.

alumina

A ceramic material made of aluminum oxide. Alumina is often used as a substrate, or underlying layer, for experiments. Alumina can be mixed with various amounts of titania (titanium dioxide) to change its properties as a substrate.

aluminum

A silvery-white, metallic element with good conductive and thermal properties.

atomic force microscope (AFM)

A scanning probe microscopy instrument capable of revealing the structure of samples. The AFM uses a sharp metal tip positioned over a conducting or non-conducting substrate and the surface topography is mapped out by measuring the mechanical force exerted on the tip. See scanning probe microscopy.

B

biomimetics

The study of the structure and function of biological substances to develop man-made systems that mimic natural ones; imitating, copying, or learning from biological systems to create new materials and technologies.

biopolymer

A polymer found in nature. DNA and RNA are examples of naturally occurring biopolymers. See also polymer.

biosensor

A sensor used to detect a biological substance (for example: bacteria, blood gases, or hormones). Biosensors often make use of sensors that are themselves made of biological materials or of materials that are derived from or mimic biological materials.

biosynthesis

The process by which living organisms produce chemical compounds.

block copolymers

Self-assembled material composed of long sequences of "blocks" of the same monomer unit, covalently bound to sequences of unlike type.

buckyball

See fullerene.

C

carbon

A nonmetallic element found in all living things. Carbon is part of all organic compounds and, in combined form, of many inorganic substances. Diamonds, graphite, and fullerenes are pure forms of carbon.

carbon nanotubes

Long, thin cylinders of carbon, discovered in 1991 by S. Iijima. These large macromolecules are unique for their size, shape, and remarkable physical properties. They can be thought of as a sheet of graphite (a hexagonal lattice of carbon) rolled into a cylinder. The physical properties are still being discovered. Nanotubes have a very broad range of electronic, thermal, and structural properties that change depending on the different kinds of nanotube (defined by its diameter, length, and chirality, or twist). To make things more interesting, besides having a single cylindrical wall (Single Walled Nanotubes or SWNTs), nanotubes can have multiple walls (MWNTs)--cylinders inside the other cylinders. Sometimes referred to simply as nanotubes.

cell

A small, usually microscopic, membrane-bound structure that is the fundamental unit of all living things. Organisms can be made up of one cell (unicellular; bacteria, for example) or many cells (multicellular; human beings, for example, which are made up of an estimated 100,000 billion cells.)

cell adhesion

The bonding of cells to surfaces or to other cells. Protein molecules at the surface of cells are generally the glue involved in cell adhesion.

cell recognition

The process by which a cell in a multicellular organism interprets its surroundings.

characterization

Analysis of critical features of an object or concept.

chemical vapor deposition (CVD)

A technique used to deposit thin layers of coatings on a substrate . In CVD, chemicals are vaporized and then applied to the substrate using an inert gas such as nitrogen as a carrier. CVD is used in the production of microchips, integrated circuits, sensors, and protective coatings.

chemical vapor transport

A technique similar to CVD used to grow crystal structures.

chemisorption

The process by which a liquid or gas is chemically bonded to the surface of a solid.

colloids

Very fine solid particles that will not settle out of a solution or medium. Smoke is an example of a colloid, being solid particles suspended in a gas. Colloids are the intermediate stage between a truly dissolved particle and a suspended solid, which will settle out of solution.

composite

A material made from two or more components that has properties different from the constituent materials. Composite materials have two phases: matrix (continuous) phase, and dispersed phase (particulates, fibers). For example, steel-reinforced cement is a composite material. The concrete is the matrix phase and the steel rods are the dispersed phase. The composite material is much stronger than either of the phases separately.

computational chemistry

A branch of theoretical chemistry with the goal of creating computer programs to calculate the properties of molecules (such as total energy, dipole moment, and vibrational frequencies) and to apply these programs to concrete chemical objects.

copolymerization

The process of using more than one type of monomer in the production of a polymer , resulting in a product with properties different from either monomer. See monomer, polymer.

crystallography

The process of growing crystals.