A heat sink, and cooled electronic structure and cooled electronic apparatus utilizing the heat sink, are provided. The heat sink is fabricated of a thermally conductive structure which includes one or more coolant-carrying channels and one or more vapor-condensing channels. A membrane is disposed between the coolant-carrying channel(s) and the vapor-condensing channel(s). The membrane includes at least one vapor-permeable region, at least a portion of which overlies a portion of the coolant-carrying channel(s) and facilitates removal of vapor from the coolant-carrying channel(s) to the vapor-condensing channel(s). The heat sink further includes one or more coolant inlets coupled to provide a first liquid coolant flow to the coolant-carrying channel(s), and a second liquid coolant flow to condense vapor within the vapor-condensing channel(s).