A method of forming a component includes depositing a ceramic material within an open-cell void of a polymer body. The ceramic material deposited around the periphery of the open-cell void structure forms a thermally-conductive path through the polymer body. The ceramic material circumscribes an open volume extending the entire length of the thermally-conductive path that is filled with a sealant such that fluids are incommunicable from the first surface to the second surface via the thermally-conductive path. A method of forming a heat exchanger includes forming a plurality of plates, each plate formed as a thermally-conductive polymer body. The method of forming the heat exchanger further includes arranging the plurality of plates within a housing to form a plate and frame heat exchanger configured to place a first flowpath in a heat exchange relationship with a second flowpath.