Superbiphilic patterned nanowires with wicking for enhanced pool boiling heat transfer

The boiling performance, represented by the heat transfer coefficient (HTC) and critical heat flux (CHF), must be enhanced because the energy demand of industrial processes that generate a lot of heat increases under extreme conditions. Surface manipulations have been used to improve boiling performance by controlling interfacial characteristics. Specifically, biphilic or superbiphilic patterned surfaces have been widely utilized to enhance HTC and CHF. However, it remains a challenging issue to improve CHF on superbiphilic surfaces with wicking phenomena due to the suppression of liquid supply in hydrophobic regions. In the present work, to investigate the mechanism and experimentally break through the limits of CHF enhancement, artificially patterned superbiphilic (SBPI) surfaces with different superhydrophobic (SHPO) area fractions were produced, and conducted pool boiling heat transfer. By artificially promoting nucleation, all SBPI surfaces demonstrated a higher HTC than homogeneous wettability surfaces. Considering dynamic wicking and bubble behaviors, the SBPI successfully broke through the CHF of homogeneous superhydrophilic surfaces. It is concluded that the non-dimensional liquid supply factor, which reflects both wicking and bubble behaviors, is essential to design structured surfaces during boiling. The results can contribute to a strategy for further improving boiling performance by controlling wettability on nanoscale interfaces.