In accordance with various embodiments, a printed structure of a flex circuit assembly includes a plurality of adjacent land portions formed on a heat conductive stiffener member and which support electrically conductive paths for connection to an integrated circuit. A corresponding plurality of separation channels are formed between the adjacent electrically conductive paths, and thermal energy generated by operation of the integrated circuit is transferred through the separation channels to the stiffener member. In some embodiments, the separation channels retain a fluid, such as air or a low density inert gas, which flows through the separation channels in response to rotation of a rotatable member adjacent the flex circuit assembly. In other embodiments, a dielectric, thermally conductive material fills the separation channels.