Photothermal Self-Excitation of a Phase-Controlled Microcantilever for Viscosity or Viscoelasticity Sensing


Mouro, João, Paoletti, Paolo ORCID: 0000-0001-6131-0377, Sartore, Marco, Vassalli, Massimo and Tiribilli, Bruno (2022) Photothermal Self-Excitation of a Phase-Controlled Microcantilever for Viscosity or Viscoelasticity Sensing Sensors, 22 (21). p. 8421. ISSN 1424-8220, 1424-8220

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Abstract

This work presents a feedback closed-loop platform to be used for viscosity or viscoelasticity sensing of Newtonian or non-Newtonian fluids. The system consists of a photothermally excited microcantilever working in a digital Phase-Locked Loop, in which the phase between the excitation signal to the cantilever and the reference demodulating signals is chosen and imposed in the loop. General analytical models to describe the frequency and amplitude of oscillation of the cantilever immersed in viscous and viscoelastic fluids are derived and validated against experiments. In particular, the sensitivity of the sensor to variations of viscosity of Newtonian fluids, or to variations of elastic/viscous modulus of non-Newtonian fluids, are studied. Interestingly, it is demonstrated the possibility of controlling the sensitivity of the system to variations of these parameters by choosing the appropriate imposed phase in the loop. A working point with maximum sensitivity can be used for real-time detection of small changes of rheological parameters with low-noise and fast-transient response. Conversely, a working point with zero sensitivity to variations of rheological parameters can be potentially used to decouple the effect of simultaneous external factors acting on the resonator.

Item Type: Article
Uncontrolled Keywords: Phase-Locked Loop, microcantilever, sensing, viscosity, viscoelasticity, elastic modulus, viscous modulus
Depositing User: Symplectic Admin
Date Deposited: 07 Nov 2022 09:14
Last Modified: 24 Jan 2026 03:56
DOI: 10.3390/s22218421
Open Access URL: https://www.mdpi.com/1424-8220/22/21/8421
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3166013
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