Enhanced Capillary Performance of Multiscale Ultrathin Titanium Wicks Guided by Modified Wicking Dynamics

Ultrathin titanium vapor chambers with wicks fabricated by ultrafast laser direct writing provide a promising solution for future electronics' lightweight thermal management. However, despite being a powerful tool for wick manufacturing, the application of ultrafast laser is restricted by its low fabrication efficiency and imperfect model for wick design. Herein, a multiscale titanium wick with stable superhydrophilic nano ripples and mi-crogrooves was high-efficiently fabricated by a multi-beam femtosecond laser processing technology. A modified wicking dynamic model was proposed for ultrafast laser manufactured microgroove wick design. It considered the extra capillary force by laser induced nanoripple and viscous resistance of the narrow V-shape grooves, which is ignored in the classic model. The prediction error of wicking performance reduced from 72.9 % to 4.5 %. Compared to the conventional V-shape design the optimized microgrooves wick improved by 56.7 % and exhibited capillary performance parameter (K/Reff) of 1.88 mu m at a thickness of 80 mu m, which outperformed most of the recently reported data. The modified model, multiscale high-performance wick, and its highly efficient fabrication method propose a universal and handy approach for accurate and quantitative wick design and manufacturing.