A breakthrough in the electroactive polymers used to make electrically controlled micro “artificial muscles” could be important for future drug delivery in the body, as well as a having a host of other applications.

The new research, conducted at the Australian National Fabrication Facility’s (ANFF) materials node at the University of Wollongong (UOW) in NSW has produced materials which, unlike earlier versions, do not need to be immersed in an electrolyte solution. They are self-sufficient and can even work in air.

The tiny “muscles” are comparable in size to human hair, between 20 and 150 microns in diameter. The ANFF’s OptoFab node at Macquarie University played a vital collaborative role, using its technological know-how to cut the materials down to the necessary micro dimensions. “As far as I know, this is the first time anyone has scaled them down to this size,” says Prof Gursel Alici, head of the Intelligent Nano-Tera Systems Research Group at UOW.

The polymer actuator is sandwiched between two active polymer layers. When an electrical potential difference is applied between the active layers, this multi-layer structure bends and will retain its position for hours or maybe even days. Applying a reverse potential will bend it back through its original position to the other side.

“Devices made using these smart materials will act in a fashion similar to real muscles, but unlike other micro-devices will use less power, and will be biocompatible, compliant and non-toxic,” says Gursel.

The muscles could be incorporated in micro-optoelectromechanical systems, with potential applications that include micropumps, microswitches, microgrippers and microcantilevers, which could be used for moving, positioning or holding micro devices and objects. One big possibility is for drug delivery inside the body, in which microcantilevers could be used to release controlled amounts of drugs from tiny reservoirs.

This project has been undertaken within the scope of an Australian Research Council Discovery Project DP0878931.

Photo: A tiny micro “muscle” made of electroactive polymer layers will bend when an electrical potential difference is applied
Credit: G. Alici et al.

Intelligent Nano-Tera Systems Research Group, University of Wollongong, Gursel Alici, Tel: +61 2 4221 4145, gursel@uow.edu.au, www.electromaterials.edu.au/anff/index.html