INS2-1019
Direct Measurement and analysis of intermolecular forces using a Surface Forces Apparatus (SFA)
Topic
S2. High-End Characterization/Polymer Physics/Properties
When and Where
Oct 1, 2026
11:35 - 12:00
Room 103
Session Chairs
Soo-Hyung CHOI
Presenter(s)
DONG WOOG LEE (Ulsan National Institute of Science and Technology)
Co-Author(s)
Abstract
Measuring forces at the nanoscale provides valuable insights into the affinity between molecules, which can be further related to the miscibility and compatibility of materials. Several techniques have been developed to directly probe such interaction forces, including atomic force microscopy and magnetic/optical tweezers. Among these, the Surface Forces Apparatus (SFA) has been employed for decades to measure forces between two surfaces. A key advantage of the SFA over other methods is its ability to determine the absolute distance between surfaces, rather than a relative distance defined by a pseudo-hard wall. Furthermore, owing to its interferometric distance measurement and well-defined geometry, the SFA enables sub-nanometer resolution and a rigorous conversion of measured forces into interaction energies. It also allows direct quantification of adhesion, hysteresis, and energy dissipation during repeated approach–separation cycles, thereby bridging molecular interactions with macroscopic properties such as adhesion, lubrication, and material compatibility. In this presentation, I will highlight several studies on intermolecular force measurements, demonstrating how the SFA can provide fundamental insights into structure–property relationships through investigations of interactions between (i) host–guest pairs and (ii) biopolymers and various functional groups.
