Elastomers, which can transform electrical energy into mechanical energy, have a wide variety of applications, i.e. powering windscreen wipers, sound generation, and operating camera lenses. By surrounding the synthetic material with electrodes and applying operation voltage, it expands laterally. In the field of medicine, this principle is promising for the development of artificial muscles for treating severe incontinence, as the consortium recently communicated.
To provide the necessary strain, micrometer-thick silicone layers need an operation voltage of several hundred volts, which is by far too high for applications within the human body. In contrast, nanometer-thin layers require only a few volts. To generate forces necessary to reach continence, several thousand layers have to be put on top of each other.
Current manufacturing methods do not allow the efficient fabrication of such layered nanostructures. The team of Prof. Müller from the Biomaterials Science Center of the University of Basel, together with researchers of Empa, has developed a deposition method to prepare extremely flat silicone layers that are much thinner than a micron. The roughness is smaller than one nanometer. For this purpose, silicone molecules in solution are sprayed assisted by high voltages – termed electrospray deposition.
Usually electrospraying is based on direct current. The researchers from Basel, however, employ an alternating current. “This rather simple deposition technique has a huge potential, as it is adaptable to the industrial requirements for producing artificial muscles as well as powering windscreen wipers”, Bert Müller said. He expects that patients suffering from severe incontinence could benefit from the technology.
Florian M. Weiss, Tino Töpper, Bekim Osmani, Sven Peters, Gabor Kovacs, and Bert Müller Electrospraying Nanometer-Thin Elastomer Films for Low-Voltage Dielectric Actuators Advanced Electronic Materials 2016, 1500476 | DOI: 10.1002/aelm.201500476
Florian M. Weiss, Tino Töpper, Bekim Osmani, Hans Deyhle, Gabor Kovacs, and Bert Müller Thin Film Formation and Morphology of Electro-sprayed Polydimethylsiloxane Langmuir 2016 | DOI: 10.1021/acs.langmuir.6b00476
Elisa Fattorini, Tobia Brusa, Christian, Gingert, Simone E. Hieber, Vanessa Leung, Bekim Osmani, Marco D. Dominietto, Philippe Büchler, Franc Hetzer, and Bert Müller Artificial Muscle Devices: Innovations and Prospects for Fecal Incontinence Treatment Annals of Biomedical Engineering 2016 | DOI: 10.1007/s10439-016-1572-z