Robots move in response to light
Researchers on the Hervanta campus of Tampere University are developing materials that move in response to light. Professor Arri Priimägi leads the Smart Photonic Materials (SPM) Group that will receive €1.5 million of ERC funding between 2016 and 2021.
“Our research interests focus on light-responsive materials. This means that we develop materials that can change their length or thickness when light is shined on them. In the future, we will be able to utilise these light-induced movements, for example, in photonics applications and different sensor surfaces,” says Priimägi.
Priimägi’s research has also earned him national recognition. The Academy of Finland recently awarded Priimägi in recognition of his scientific courage. The Academy has appointed Priimägi as Academy Research Fellow for the term running from 2014 to 2019.
One of SPM’s goals is to create colour-changing lasers. Lasers are used in the field of spectroscopy to determine the composition of different materials. There is a need for adjustable lasers, as materials react differently to different colours of laser light.
The scope of SPM’s research has expanded to cover light robotics. The team of researchers has demonstrated that the movement of small plastic objects can be controlled with light. Their research has been inspired by the natural world.
“We have, for example, created an artificial iris that responds to light in the same way as a human eye. We have also developed an optical Venus flytrap and most recently a structure that mimics the behaviour of nocturnal flowers and “blossoms” in the dark when certain humidity conditions are met.”
Light-responsive plastic objects are made of liquid crystal polymers or elastomers. Elastomers are also used, for example, in car tyres. They are highly stretchable but revert to their original shape after the force or stress is released.
“The liquid crystalline state of the material allows us to align its molecules to face in a specific direction and thereby control the movement of the entire object,” says Priimägi.
The goal of the team of researchers is to develop robots that are capable of working as independently as possible and perform a variety of tasks.
“We have set our sights on developing materials that automatically adapt to their environment.”
Light-controlled robots range in size from one to a couple of centimetres.
“The amount of power is often the number one priority for industry, whereas our focus is on small objects. We will have to discuss the potential applications of our findings with industry, but up until now our primary preoccupation has been basic research,” says Priimägi.
The best potential applications of the technology could be in areas where small-scale objects must be remotely controlled. As light-controlled materials can be pre-programmed to move in a certain way, the robots can perform tasks autonomously.
Light tells many stories
Priimägi has always considered light a captivating phenomenon. Light gives us insights into our universe, and we can attempt to understand these insights by conducting scientific experiments.
“Light is the source of the majority of the information that we receive through our senses. From a technological perspective, it is an interesting research topic: we can gaze at the starts or explore microscopic phenomena.”
Light is both a particle and a wave. Priimägi finds this duality fascinating.
“We know that the answer to the philosophical problem of this wave-particle duality depends on the experimental settings. The nature of light is a philosophically interesting question,” says Priimägi.
Text: Jaakko Kinnunen