Surface force apparatus for nanorheology under large shear strain

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• Understanding the rheology of nanoconfined fluids is crucial for various applications.
• Traditional surface force apparatus (SFA) methods have limitations in probing large shear amplitudes and confinement ranges.

Purpose of the Study:

• To introduce a novel surface force apparatus (SFA) capable of investigating the rheological properties of nanoconfined media.
• To extend the accessible range of shear strain and confinement in SFA experiments.

Main Methods:

• Development and implementation of a closed-loop feedback system in the SFA.
• Control of either applied normal load or medium thickness during shear experiments.
• Utilizing hexadecane as a model nanoconfined medium to demonstrate instrument performance.

Main Results:

• The enhanced SFA successfully probed rheology at large shear amplitudes (up to 500 microm).
• Feedback control significantly expanded the attainable confinement and shear strain ranges.
• Demonstrated the instrument's capability in characterizing the rheological behavior of hexadecane under nanoconfinement.

Conclusions:

• The developed SFA offers a powerful tool for studying nanoconfined rheology beyond previous limitations.
• This advancement enables more comprehensive investigations into the flow behavior of materials at the nanoscale.
• The instrument's performance with hexadecane validates its potential for diverse soft matter research.