Viscoelasticity mapping method based on the contact resonance of a piezoelectric cantilever

In this work, we propose a novel viscoelastic property mapping method/system for polymers based on the contact resonance of a piezoelectric unimorph cantilever. The viscoelastic properties of materials are derived from the contact resonance frequency (CRF) and quality factor (Q-factor) of the cantilever-sample system by using a cantilever vibration model. The performance of this system is examined by testing on a composite specimen made of nitrile rubber (NBR) and epoxy. It is shown that the dynamic modulus of the NBR is smaller than that of the epoxy, while the loss factor of the former is larger than the latter, which is consistent with the measurement results by using dynamic nanoindentation. The proposed method is very promising for in situ viscoelasticity mapping, which can be very useful in discrimination of unknown mixtures, interface characterization or elastography of superficial organs for medical diagnosis. (C) 2014 Elsevier Ltd. All rights reserved.