Silicone is used for e.g. contact lenses. Photo: Colourbox

Silicone is for artificial muscles too

Wednesday 06 May 15
by Bertel Henning Jensen
Silicone is used for all kinds of everyday items, but the material has still not been examined in any real depth. A new DKK 3 million project scheduled to run over three years is now set to change all that.

It is in our textiles, our soap, our toys, and hundreds of other products. It is all around us, and sometimes inside us as well. It is silicone. Despite this, the field of silicone rubber has not yet been examined in any real depth. But that is all set to change now.

Backed by DKK 3 million from the Danish Council for Independent Research, Frederikke Bahrt Madsen, a postdoc at DTU Chemical Engineering, will be spending the coming three years searching for new ways to make silicone rubber and getting to know the elastic material a little better. Her research will—quite literally—touch the lives of most people in Denmark in one way or another.

“Silicone and silicone rubber are put to a great many uses, but the little research has been done into the actual background of how it functions from both chemical and physical perspectives. So now it’s time for us to go back to the beginning to find out how we can alter the properties of silicone rubber to make it an even better product,” explains Frederikke Bahrt Madsen, the recipient of the grant.

“Silicone rubber consists of silicone polymers, which are long chains of molecules cross-linked to form an elastic network that can return to its original form,” she says.

“But it needs a ‘filler’ to make it strong enough, and for the next three years I’ll be working in the laboratory, putting different silicone polymers together in new ways. Our purpose is to see if we can make the networks broader and smarter by creating self-perpetuating silicone rubber that will allow us to eliminate the use of silica fillers. If we succeed, we will open the door to reusable silicone materials.”

"Silicone has a number of fascinating properties; our bodies readily accept it, for example. This is one of the reasons why so much use is made of silicone in the pharmaceutical industry"
Postdoc Frederikke Bahrt Madsen, DTU Chemical Engineering

Industry on board
The objective is to create ‘new’ silicone that is stronger, more elastic, and better at returning to its original form than the forms of silicone we know today. The project is scheduled to run for the next three years, and will involve colleagues from the universities of Linz in Austria and Lyon in France, from where Frederikke Bahrt Madsen will draw on expertise in the mechanical and optical properties of rubber.

The use of silicone today is so widespread that we are all almost constantly in contact with it in one form or another. There is therefore a huge range of properties that need to be examined.

“Silicone has a number of fascinating properties; our bodies readily accept it, for example. This is one of the reasons why so much use is made of silicone in the pharmaceutical industry,” says Frederikke.

For the same reason, she has set up a partnership for her project with Coloplast. The stoma specialist is to make facilities available for the project so Frederikke can examine how the products function as what is known as skin adhesive. This is used, for example, when a stoma bag has to be attached to the skin of a patients stomach.

Future scenarios
The use of silicone is set to play a key role in upcoming technologies—in the field of wave energy, for instance, or in artificial muscles, which was the subject of Frederikke Bahrt Madsen’s PhD thesis.

I wanted to build up a better understanding of how the mechanical properties function, and then use this to improve silicone rubber. If we can change silicone rubber, we may be able to find new ways to use it. After all, plastic and silicone have revolutionized our everyday products, and I find this fascinating. Silicones everywhere you look, she says.

Article in DTUavisen no. 5, May 2015.