Proceedings of 41st Danubia-Adria Symposium Advances in Experimental Mechanics (pp. 95-98)
Soft piezoelectric materials, such as hydrogels, have gained importance for diverse biomedical applications due to the possibility to mimic biological tissues, including cell signaling. It is complex to accurately characterize their piezoelectric activity due to spatial inhomogeneity of the material, low electric outputs, instability of the signal, viscoelastic damping and high impedance. Also, determination of piezoelectric coefficients, important for analytical and numerical modelling is still challenging.
Measuring the low voltage output from piezoelectric hydrogels, which are soft and often deformable, requires highly sensitive instruments and careful noise mitigation. Common tools include high-impedance voltmeters, lock-in amplifiers, picoammeters, and low-noise or charge amplifiers to capture and condition weak signals. Techniques like Kelvin (four-terminal) sensing help reduce errors from contact resistance, especially in highimpedance materials. Advanced systems, such as portable devices with electrochemical impedance spectroscopy (EIS), enable precise low-current measurements. For evaluating piezoelectric coefficients, methods like laser Doppler vibrometry (LDV) and piezoresponse force microscopy (PFM) are used, often supported by numerical analysis for complex soft materials.
This paper presents measurement methods forpiezoelectric hydrogels, with case study of custom measurement setup for low output voltage from actuated piezoelectric hydrogels and key aspects of good system design.
This paper is supported by the project No. 451-03-137/2025-03/200107 and No. 451-03-136/2025-03/200378, Ministry of Science, Technological Development and Innovation, Republic of Serbia.