Patent ID: 8613881

Claim:
A method of manufacturing a polymer foam layer, the method comprising: forming a precursor layer comprising a polymer foam precursor composition, and a filler composition comprising a plurality of magnetic, electrically conductive particles, wherein the precursor layer has a first surface and a second opposite surface, and is formed having the first surface disposed on a first removable layer; foaming the foam precursor composition to form a foamed layer, wherein the foamed layer has a plurality of cells; applying to the foamed layer a magnetic field of a strength and for a time effective to align the magnetic, electrically conductive particles into mutually isolated columns having a first end and a second end, wherein the particles essentially continuously span the foam layer between the first surface and the opposite second surface; curing the foamed layer; and prior to or during curing, exposing the first removable layer to heat at a temperature and for a time effective to allow the first ends of the columns adjacent to the first removable layer to partially embed in the first removable layer.