Step 1: Prestretching

Make sure to start with a clean working area. It is not necessary to have a perfectly clean actuator, but dust and debris can damage the membrane, leading to a failed actuator.

Do not use gloves for this step. The VHB sticks to the glove material and makes working with it difficult.

	Cut a square of VHB slightly larger than the stencil area Place the VHB with the red side facing down (sticky side up) Draw the outline of the stencil onto the VHB 4910 in pen. Stray pen marks outside the circle are fine. Some pens use an ink which dissolves VHB 4910 and leads to rupture during the prestretching process. The exact types of pens are not known, but generally low-end ball point pens should work.
	Cut out the stencil This does not need to be perfectly cut out. A little area of tape outside the drawn circle makes attaching to the frame easier.  Pay careful attention to not notch the outer edge. This can cause the material to tear when it is actuated. Remove the red backing material from the VHB tape.  A good way to remove the backing is to stretch the tape parallel to the surface to separate a small section and then pull perpendicularly (as seen in video below).

	Next, attach the membrane on four opposite points to the acrylic ring, such that the inside of the drawn line aligns with the outer edge of the ring.  Attach the membrane in between each of the four attached points to the ring, such that there are eight equally spaced attachment points along the ring. Go Slow! Rushing the prestretching step can result in torn actuators, which will need to be redone.
	Now, go along the ring and attach the whole membrane to the ring. Align the membrane such that the inside of the drawn line aligns with the outer edge of the acrylic frame. If the membrane was not perfectly aligned when first attached, gently remove the section and reattach in correct alignment (as seen in video on left).

Bibliography

Keplinger et al. (2012) Harnessing snap-through instability in soft dielectrics to achieve giant voltage-triggered deformation.

Keplinger et al. (2013) Stretchable, transparent, ionic conductors.

Koh et al. (2009) Maximal energy that can be converted by a dielectric elastomer generator.

Wissler and Mazza (2007) Mechanical behavior of an acrylic elastomer used in dielectric elastomer actuators.

Pelrine et al. (2001) Dielectric elastomers: generator mode fundamentals and applications.

Pelrine et al. (2000) High-Speed Electrically Actuated Elastomers with Strain Greater Than 100%.

Röntgen WC. (1880) Ueber die durch Electricität bewirkten Form—und Volumenänderungen von dielectrischen Körpern.

Suo, Zhigang (2010) Theory of dielectric elastomers.

Contributors

Philipp Rothemund