Dielectric elastomer actuators (DEA) are smart lightweight flexible materials integrating actuation, sensing, and structural functions. The field of DEAs has been progressing rapidly, with actuation strains of over 300% reported, and many application concepts demonstrated. However many DEAs are slow, exhibit large viscoelastic drift, and have short lifetimes, due principally to the use of acrylic elastomer membranes and carbon grease electrodes applied by hand. We present here a DEA-driven tuneable lens, the world’s fastest capable of holding a stable focal length. By using low-loss silicone elastomers rather than acrylics, we obtain a settling time shorter than 175 μs for a 20% change in focal length. The silicone-based lenses show a bandwidth 3 orders of magnitude higher compared to lenses of the same geometry fabricated from the acrylic elastomer. Our stretchable electrodes, a carbon black and silicone composite, are precisely patterned by pad-printing and subsequently cross-linked, enabling strong adhesion to the elastomer and excellent resistance to abrasion. The lenses operated for over 400 million cycles without degradation, and showed no change after more than two years of storage. This lens demonstrates the unmatched combination of strain, speed and stability that DEAs can achieve, paving the way for complex fast soft machines.

Ultrafast all-polymer electrically tunable silicone lenses / Maffli, Luc; Rosset, Samuel; Ghilardi, Michele; Carpi, Federico; Shea, Herbert. - In: ADVANCED FUNCTIONAL MATERIALS. - ISSN 1616-301X. - ELETTRONICO. - 25:(2015), pp. 1656-1665. [10.1002/adfm.201403942]

Ultrafast all-polymer electrically tunable silicone lenses

CARPI, FEDERICO;
2015

Abstract

Dielectric elastomer actuators (DEA) are smart lightweight flexible materials integrating actuation, sensing, and structural functions. The field of DEAs has been progressing rapidly, with actuation strains of over 300% reported, and many application concepts demonstrated. However many DEAs are slow, exhibit large viscoelastic drift, and have short lifetimes, due principally to the use of acrylic elastomer membranes and carbon grease electrodes applied by hand. We present here a DEA-driven tuneable lens, the world’s fastest capable of holding a stable focal length. By using low-loss silicone elastomers rather than acrylics, we obtain a settling time shorter than 175 μs for a 20% change in focal length. The silicone-based lenses show a bandwidth 3 orders of magnitude higher compared to lenses of the same geometry fabricated from the acrylic elastomer. Our stretchable electrodes, a carbon black and silicone composite, are precisely patterned by pad-printing and subsequently cross-linked, enabling strong adhesion to the elastomer and excellent resistance to abrasion. The lenses operated for over 400 million cycles without degradation, and showed no change after more than two years of storage. This lens demonstrates the unmatched combination of strain, speed and stability that DEAs can achieve, paving the way for complex fast soft machines.
2015
25
1656
1665
Maffli, Luc; Rosset, Samuel; Ghilardi, Michele; Carpi, Federico; Shea, Herbert
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1085506
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