English Abstract

Improved Quantification of Nanoscale Viscoelasticity Measurements by Nanorheological Atomic Force Microscopy

Makiko ITO
Xiaobin LIANG
Department of Chemical Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo, Japan
Nippon Gomu Kyokaishi,(2023),96(5),113-118 Original Paper in Japanese

Nanorheological atomic force microscopy (AFM) is a measurement technique that maps dynamic viscoelasticity with nanoscale spatial resolution. The technique combines dynamic measurements with quasi-static force curve measurements, allowing quantification of the contact area using a theoretical model of contact elasticity and, therefore, the dynamic modulus. However, the nano-viscoelasticity measured by nanorheological AFM is not in perfect agreement with the macro-viscoelasticity measured by a rheometer. To improve the quantitative performance of the dynamic modulus, a variable was introduced to correct for the difference from the contact area of Johnson-Kendall-Roberts theory. The load dependence of the storage stiffness of polydimethylsiloxane (PDMS) and styrene-butadiene rubber (SBR) was investigated to determine variables for each measurement frequency. The novel analytical method gives results in better agreement with the macroscopic measurement method.

Keywords: Viscoelasticity, Nanorheology, Dynamic Modulus, Atomic Force Microscopy, Johnson-Kendall-Roberts Theory