Enhanced measurement of broadband nanomechanical property of polymers using atomic force microscope

Abstract

A control-based approach to achieve accurate indentation and broadband nanomechanical quantification using atomic force microscope is proposed and utilized to measure four different polymers. For broadband nanomechanical measurement, conventional method is limited by its inability to account for the dynamics effect of the piezoelectric actuator and the cantilever fixture, and the lateral-vertical coupling effect on the cantilever deflection. The proposed approach substantially improved the accuracy of indentation and nanomechanical measurements by utilizing control technique to compensate for these adverse effects. A polydimethylsiloxane sample and three low-density polyethylene samples with different densities were measured by using this approach. The results showed that the viscoelasticity of these four polymer samples can be consistently measured over a large frequency range (100 Hz to 6 kHz) with merely 1 sec. measurement time.