Methods for manufacturing a composite material and composite materials are provided. The method may include preparing a metal foam, preparing a mixture including the metal foam and a curable polymer, curing the curable polymer of the mixture to obtain a composite material, and performing a planarization treatment. The planarization treatment may be performed on the metal foam before preparing the mixture, on the mixture before curing the curable polymer, and/or on the composite material. The composite materials may include a metal foam and a polymer that is on a surface and/or in pores of the metal foam. The composite material may have a surface roughness of 2 μm or less and/or may have a thermal resistance of 0.5 Kin2/W or less at 20 psi.