An innovation with a tiny motor one day could drive developments in materials science and medicine. Electric vehicles, powered by macroscopic electric motors, are becoming commonplace. Developments are also occurring at the molecular level, where scientists are grappling with the same challenges to produce more powerful and energy efficient motors.
A multidisciplinary team (experimental, computational and theoretical chemists) led by Northwestern University has made an electric motor that cannot be seen with the naked eye. This is an electric motor on the molecular scale.
The motor can convert electrical energy into unidirectional motion at the molecular level and it has a future use for materials science and medicine, as with the application of electric molecular motors and biomolecular motors to transfer drugs around the human body.
According to lead researcher Sir Fraser Stoddart: “We have taken molecular nanotechnology to another level…This elegant chemistry uses electrons to effectively drive a molecular motor, much like a macroscopic motor. While this area of chemistry is in its infancy, I predict one day these tiny motors will make a huge difference in medicine.”
The motor is just two nanometers wide. At the basis is a certain type of molecule with interlocking rings known as catenanes. These are held together by powerful mechanical bonds, so the components could move freely relative to each other without falling apart.
The electric molecular motor is based on a [3]catenane whose components ― a loop interlocked with two identical rings ― are redox active, that is they undergo unidirectional motion in response to changes in voltage potential. The researchers discovered that two rings are needed to achieve this unidirectional motion.
The operation of molecules that perform the function of a motor (which work by converting external energy into directional motion) proved challenging. The researchers spent more than four years on the design and synthesis of their electric molecular motor. This required careful research into synthesis, measurements and computational chemistry.
The advantages with the new invention are that the motor is easy to make and produces no waste. In addition, for the future, the work seemingly takes molecular nanotechnology to another level.
The next phase is to attach many of the motors to an electrode surface to influence the surface and ultimately do carry out a specified task.
The research appears in the journal Nature. The research is simply titled “An electric molecular motor”.
