Rotaxane machine - a nanomachine inspired by Maxwell's demon

Continuing my earlier post about Maxwell's Demon, recently Professor David Leigh of the University of Edinburgh's School of Chemistry and and colleagues have built a model that mimics Maxwell's demon - an atom-sized motor that could lead to man-made nanomachines.

The molecular model of the demon is a rotaxane (mechanically-interlocked molecular architecture consisting of a dumbbell-shaped molecule that is threaded through a macrocycle or ring-like molecule.). In this rotaxane machine (nanomachine), information about the location of the molecular ring is used to move the system from equilibrium. But gathering and then implementing that information costs energy... in other words the second law of thermodynamics remains valid.

Maxwell's Demon Becomes Reality :

“Our machine has a device - or ‘demon’ if you like - inside it that traps molecule-sized particles as they move in a certain direction.

“Maxwell reasoned that if such a system could ever be made it would need energy to work. Without energy, it might appear that the perpetual motion of the molecules could power other devices in the same way as a windmill, but Maxwell reasoned that this would go against the second law of thermodynamics.

“As he predicted, the machine does need energy and in our experiment it is powered by light. While light has previously been used to energise tiny particles directly, this is the first time that a system has been devised to trap molecules as they move in a certain direction under their natural motion. Once the molecules are trapped they cannot escape.”