Atomic Elements, Molecules and Nanotechnology
Posted by Science Oxford on August 31, 2011 | comments
A sensible, simple article to underlie the risk debates.
Alison Cooper
‘The element’ at Science Oxford Live used the music of Bach played on a violin to illustrate atoms and energy. This seemed appropriate to me as Bach means ‘small’ in Welsh. Atoms are the smallest particle of a pure substance that can be told apart (classed as an element). The numbers, ratio and formation of even smaller entities such as protons, neurons, electrons, and quarks determine how the atoms will interact and combine with others to form molecules.
At this tiny scale, nothing stays still. Tiny particles are randomly moving and colliding, known as ‘Brownian motion’. This is faster in liquids than solids and faster still in gases, and increases with temperature.
Forces of attraction determine how atoms and molecules combine and the kind of structures they form, holding them together despite the Brownian motion. This in turn influences material properties, for example how hard, soft, brittle or rubbery we experience them to be.
Humans like to experiment with movements of atoms to create new substances and molecular structures. The large Hadron collider uses magnetic force to accelerate and collide materials and is capable of generating completely new atoms, heavier than those seen in nature.
Nano technology has developed from systematically combining molecules in machine-like assemblies, generating tiny structures, designed to move in a specific way or interact to serve a particular purpose, a bit like tiny gears and levers. The cohesive forces and motion mean that substances used have to be carefully selected and spread out into thin layers to elicit the desired behaviour.
Structures are built up, 2D and then 3D and combined. They can self assemble to form designed combinations where joints can be broken and remade (e.g sticky ends). This produces ‘shape shifters’ and ‘walkers’ with defined ways of generating their own motion, for example an extremely tiny ‘inch worm’ Ω.
Nano is a Greek word meaning, dwarf or very small. Just one millimetre is equivalent to one million nanometres. Professor Ned Seeman takes inspiration from Greek architecture to create these elaborate designs. DNA can be used as a nanoparticle, to build complex architectural structures (macromolecules) by manipulating the way strands combine.
Nanotechnology can be used for things such as; incredibly tiny electronic circuitry in an iPod, improved coatings to avoid rust, non stick surfaces, to improve interactions between skin and materials in sports training shoes and ballet dancers’ pointe shoes, and to protect from infection.
There is a lot of talk about the revolutionary potential of Nanotechnology. Should we worry? Very small particles can easily pass through bodies’ defences, get inside cells and interact with their natural machinery – great in terms of medicine and creams to nourish skin. Problems come if particles made for another reason are found to be harmful to people, wildlife and the environment and accidently escape or fall into the hands of someone wanting to cause harm.
This futuristic technology makes the ponderings of ancient Greek philosophers more relevant than ever. When it comes to deciding whether to accept a technology, getting to grips with classic fundamental questions like ‘where is the boundary between our body and the world outside’, ‘what makes us who we are?’ and ‘how should we direct the things we make?’, is a very good place to start.
Soft Machines, Nanotechnology and Life Prof RAL Jones
Prof Nadrain Seeman
What do you think?