Introduction to Electroactive Polymers

One of the most commonly used dielectric materials used to construct dielectric EAPs is VHB 4910 tape by 3M as shown in figure~ ef{fig:2}. It is a clear, double sided acrylic adhesive tape used for bonding transparent materials. It is also highly elastic, with the ability to stretch over 400\% without damage (Zhang 2007).

For ease of application, carbon black, also sold as lampblack, was used in experiments. More conductive electrodes such as copper and aluminum powder were found to be ineffective. Other common electrodes use are carbon grease or a mixture of carbon with silicone oil (Lochmatter 2007).

A simple method for connecting the electrode to a power supply is to use adhesive metal foil tape like the type used in stained glass.

Because the polymer is usually prestrained, it is important to have a frame holding the EAP in a stretched position. This can be accomplished by cutting an acrylic sheet to the desired configuration. The acrylic sheet is about 3mm thick and can be cut with a Dremel, or laser cutter, but it is easiest to make a score line and then snap it. The edges of the frame must be sanded down so as not to puncture the acrylic film.

subsection{Construction}

egin{figure} centering includegraphics[width=.5 extwidth]{Fig_3} caption{label{fig:3}Device used for stretching VHB 4910 tape} end{figure} The first step involved with constructing an EAP is to stretch the polymer. This requires holding onto many points along the edges of the polymer while simultaneously moving those points apart. The simplest method is to create a loop of metal shower hose that can be rotated to stretch the material. Another successful approach is to use an expanding frame like the one pictured in figure~ ef{fig:3}. The on...

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... or automotive ignition coil.

Controlling the power supply is an additional challenge depending on the intended use. Common electronic components cannot successfully control these high voltages. There are some transistors, such as MOSFETs by IXYS that can control up to 4.5 kV, but some electrical expertise is needed to utilize them, and unfortunately, it is exceedingly difficult to use them in series. This simplest method for controlling multiple transducers independently found was to use multiple proportional power supplies that are activated from an easy to control 5V. Now, the proportional power supplies require more power than is available from a basic Arduino or 555 timer IC, or many transistors can supply. So something like the circuitry from a hobby remote control vehicle was found to work effectively for manual activation of the proportional power supplies.