Electrically-controllable liquid crystal elastomer-graphite composite artificial muscles

Reported is the fabrication method and experimental results pertaining to a new class of liquid crystal elastomer-graphite (LCE-G) composites as electrically-controllable biomimetic artificial muscles. These films (10mmx20mmx0.32mm) of monodomain nematic liquid side chain crystal elastomers graphite (LSCE-G) composites were transversely pressed between uniform layers of fine graphite powder of 2 microns average diameter under a stress of 100kPa. The resulting composite expanded to (12mmx24mmxo.33mm) and had about 53% by volume embedded graphite powder. The composite became a conductor and had an effective resistivity of about 2 ohms/square on its surface and about 1 ohm/square across its thickness. Upon applying DC voltages of 0.5 to 5 volts to the samples for 4 seconds, under a stress of about 10 kPa, the sample contracted quickly in about a second to about 18mm lengthwise with an average linear strain of about 25%. The samples generally had negligible contractions in the thickness and transverse direction. The cooling was also quick and it took the sample about 4.4 seconds to revert back to its initial length.