Performance Evaluation of Wick-Free Vapor Chamber Featuring Hierarchical Laser Engineered Surfaces

Thin vapor chambers are attractive for compact electronics but become difficult to operate reliably as the vapor space approaches the millimeter scale, especially when classical wick structures are omitted. This work investigates how coupled evaporator and condenser wettability governs the performance of a 1 mm thick wick-free vapor chamber. Six configurations are evaluated by combining three condenser surface states (reference, superhydrophilic, superhydrophobic) with either a reference copper evaporator or a laser-textured superhydrophilic evaporator. Thermal performance is assessed from 10 to 40 W using the evaporator–condenser temperature difference and overall thermal resistance. The results show that the preferred condenser wettability depends on evaporator capability. With the reference evaporator, the lowest thermal resistance at 40 W is achieved with reference and superhydrophobic condensers (1.21 and 1.18 K/W). With the laser-textured evaporator, a superhydrophilic condenser provides the best performance, and the SHPI–SHPI configuration reaches 0.77 K/W at 40 W. These findings provide practical guidance for designing ultrathin wick-free vapor chambers through coordinated interface wettability selection.