paulr1234
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Filter paper that doesn't stretch
Apologies for the somewhat crudely phrased subject line.
I'm doing some research into carbon-nanotube-based electroactive polymer actuators for robotics. A common preparation is to filter the CNT+polymer
mixture through a filter paper, to then dry the resulting sheet leaving a CNT layer on one side and to then cut the material into strips. The
electrostrictive contraction of the polymer layer on top of the inactive cellulose substrate then causes a bending motion.
Applying power to these materials only causes a small reduction in the carbon=carbon bonds which creates the actuation motion. The amounts are small,
typically only 4%, so I am looking for some alternatives to ordinary filter paper, perhaps Tyvek or maybe borosilicate fibers with an inert binder.
I want to find a substrate that has the smallest possible tolerance when dry (e.g. will stretch or compress by the smallest amount possible, to
maximize the potential bending of the EAP layer.
Most suppliers/manufacturers of specialist lab filter papers record all kinds of data (particle retention, flow rate, loading capacity even tensile
strength) but I have yet to see anyone publish data on stretchability (I'm sure there's a better scientific term for this and I'd love to know it).
I was wondering whether anyone here had any thoughts on suitable materials.
Thx.
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watson.fawkes
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For isotropic
materials, it's Young's modulus.
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matei
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Inorganic membranes (such as the aluminium oxide membranes from Whatman) seem to be what you are looking for:
http://www.whatman.com/PRODAnoporeInorganicMembranes.aspx
They come in different porosities and diameters. However you need a special filtration device to hold the membrane, which is somewhat expensive.
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