# MicroMegascope based dynamic Surface Force Apparatus

## TL;DR

This paper introduces a MicroMegascope-based dynamic Surface Force Apparatus that enables precise, versatile force-distance measurements of confined liquids, capturing rheological, frictional, and interfacial features with high resolution.

## Contribution

It presents a novel, simpler, and versatile force measurement tool based on MicroMegascope technology, expanding capabilities beyond traditional Surface Force Apparatus methods.

## Key findings

- Accurately measures dynamic force profiles of confined liquids.
- Detects small interfacial features like ionic liquid layering.
- Measures rheological and frictional properties at micro to molecular scales.

## Abstract

Surface Force Apparatus (SFA) allows to accurately resolve the interfacial properties of fluids confined between extended surfaces. The accuracy of the SFA makes it an ubiquitous tool for the nanoscale mechanical characterization of soft matter systems. The SFA traditionally measures force-distance profiles through interferometry with subnanometric distance precision. However, these techniques often require a dedicated and technically demanding experimental setup, and there remains a need for versatile and simple force-distance measurement tools. Here we present a MicroMegascope based dynamic Surface Force Apparatus capable of accurate measurement of the dynamic force profile of a liquid confined between a millimetric sphere and a planar substrate. Normal and shear mechanical impedance is measured within the classical Frequency Modulation framework. We measure rheological and frictional properties from micrometric to molecular confinement. We also highlight the resolution of small interfacial features such as ionic liquid layering. This apparatus shows promise as a versatile force-distance measurement device for exotic surfaces or extreme environments.