An ultralight foam vapor chamber for mobile and aerial electronics cooling

• An ultralight foam vapor chamber – uFVC has been devised. • A blackened foam core and ultrathin-walled envelope have been incorporated. • The uFVC provides comparable thermal absorption and spreading with commercial VCs. • The achieved lightweighting is ∼80 % over commercial VCs with similar dimensions. • The uFVC is even lighter than the latest developmental graphene-enhanced VC. This study premieres a new type of vapor chamber that can achieve a remarkable ∼80 % weight reduction over state-of-the art commercial vapor chambers (e.g., ∼25 g, compared to ∼120 g with similar exterior dimensions) potentially for mobile and aerial applications while providing comparable thermal spreading and junction temperature. This achievement has been made possible by incorporating a high porosity copper foam that is blackened for superhydrophilicity and encapsulated by an ultrathin-walled (∼50 µm) envelope via electro/electroless plating – that is, an ultralight foam vapor chamber (uFVC). This article details its thermal absorption and spreading characteristics subjected to natural convection as well as the fabrication process. The uFVC spreads heat via latent heat conversion of an encapsulated deionized water. Blackened foam ligaments enhanced capillary forces to transport the deionized water within the ultrathin-walled envelope that further facilitates heat rejection to the surroundings. The achieved effective density of the uFVC as a measure of lightweighting is ρ eff ∼ 1,000 kg/m 3 in sharp contrast to ρ eff ∼ 9,000 kg/m 3 for a pure copper plate, ρ eff ∼ 5,000 kg/m 3 for a state-of-the art commercial vapor chamber, with being even lighter than the latest developmental graphene-enhanced vapor chamber, ρ eff ∼ 1,800 kg/m 3 .