Using surface force apparatus, diffusion and velocimetry to measure slip lengths

Area of Science:

• Physics
• Physical Chemistry
• Materials Science

Background:

• Determining liquid slip lengths near smooth surfaces presents significant challenges.
• The relevant length scales span from nanometers to hundreds of nanometers.
• Various experimental techniques have been employed to address this problem.

Purpose of the Study:

• To review and discuss three prominent methods for measuring slip lengths.
• To highlight recent instrumental progress in the field.
• To provide a comprehensive overview of current approaches to slip length determination.

Main Methods:

• Surface Force Apparatus (SFA): Measures forces between surfaces to infer slip.
• Diffusion-based methods: Utilizes the movement of molecules to quantify slip.
• Velocimetry techniques: Directly measures fluid velocity profiles near the wall.

Main Results:

• Each method offers unique insights into slip phenomena at the nanoscale.
• Recent advancements have improved the precision and applicability of these techniques.
• Understanding slip length is crucial for predicting fluid behavior in micro/nanofluidic devices.

Conclusions:

• The reviewed techniques, enhanced by recent progress, provide valuable tools for slip length measurement.
• Accurate slip length determination is essential for advancements in microfluidics and nanotechnology.
• Continued development in instrumentation will further refine our understanding of nanoscale fluid dynamics.