Observation of a Large Slip Effect in the Nanoscale Flow of Highly Viscous Supercooled Liquid Metals

Understanding and controlling the flow of materials confinedinchannels play important roles in science and engineering. The generalno-slip boundary condition will result in it being more challengingto drive the flow as the channel size decreases to the nanoscale,especially for highly viscous liquids. Here, we report the observationof a large boundary slip in the nanoscale flow of highly viscous supercooledliquid metals (with viscosities of & LSIM;10(8) Pa s), enabledby the hydrophobic treatment of smooth nanochannels. The slip lengthsignificantly depends on the pressure, which can be rationalized bythe shear-dependent viscosity. Our findings provide not only new insightsinto the field of nanofluidics but also a practical technique forresolving the challenge in the net formation of highly viscous supercooledliquid metals at the nanoscale.

Automated summary

Understanding and controlling the flow of materials in confined channels is important in science and engineering. The no-slip boundary condition makes it more challenging to drive flow at the nanoscale, especially for highly viscous liquids. This study reports the observation of a large boundary slip in the nanoscale flow of highly viscous supercooled liquid metals, enabled by hydrophobic treatment of smooth nanochannels. The slip length depends on the pressure, which can be explained by shear-dependent viscosity.