Heating elements comprising conductive polymers capable of dimensional change

A heating element which comprises:

• (A) a laminar member composed of a material which comprises an organic polymer and electrically conductive particles dispersed in the polymer in amount sufficient to render the member electrically conductive;
• and
• (B) a pair of laminar flexible electrodes which (i) are connected to opposite faces of said laminar member;
• (ii) are substantially coplanar with said laminar member;
• and (iii) are adapted to be connected to an external source of power to cause current to pass through said laminar member;
• said laminar member and laminar electrodes having a plurality of apertures through the thickness thereof, the apertures being in parallel rows and being of elongated closed cross-section and overlapping one another to permit at least one of the dimensions of the element in the plane thereof to be changed by a change in the shape of the apertures.