Microstructured wettability pattern for enhancing thermal performance in an ultrathin vapor chamber

• Published in: Case studies in thermal engineering 2021-06, Vol.25, p.100906, Article 100906
• Main Authors: Yang, Yinchuang, Li, Jian, Wang, Hongzhao, Liao, Dong, Qiu, Huihe
• Format: Article
• Language: English
• Subjects: Effective thermal conductivity; Microstructured wettability pattern; Nanostructured wick; Thermal resistance; Ultrathin vapor chamber
• ISSN: 2214-157X; 2214-157X
• DOI: 10.1016/j.csite.2021.100906

We investigated the thermal performance of a novel wettability patterned evaporator for an ultrathin vapor chamber. Because the evaporator integrates a wettability patterned substrate underneath the nanostructured mesh wick which can pin the three-phase contact lines on the hydrophilic/hydrophobic boundaries, it enlarges the area of thin-film evaporation. Microstructured wettability pattern is fabricated on the evaporator surface and the wick is pressed onto the evaporator by a micropillar array to make an intimate contact with each other. The micropillar array electroplated on the inner side of the condenser also supports a vapor core as a vapor flow path. The thermal resistance of the ultrathin vapor chamber is experimentally evaluated, and the measurement results show that the wettability pattern underneath the nanostructured mesh wick can greatly reduce the horizontal thermal resistance, giving a better temperature uniformity across the condenser side, though the vertical thermal resistance may be slightly larger than that without a wettability pattern. The highest in-plane effective thermal conductivity of a 200 μm-thick vapor chamber can reach 11914.9 W/(m·K) at 23.91 W/cm2 heat flux, which shows a 210.7% further improvement in comparison with that of the ultrathin vapor chamber with the nanostructured mesh wick only.