title: High Resolution Viscosity Measurement by Thermal Noise Detection.
abstract: An interferometric method is implemented in order to accurately assess the thermal fluctuations of a micro-cantilever sensor in liquid environments. The power spectrum density (PSD) of thermal fluctuations together with Sader's model of the cantilever allow for the indirect measurement of the liquid viscosity with good accuracy. The good quality of the deflection signal and the characteristic low noise of the instrument allow for the detection and corrections of drawbacks due to both the cantilever shape irregularities and the uncertainties on the position of the laser spot at the fluctuating end of the cantilever. Variation of viscosity below 0:03mPa·s was detected with the alternative to achieve measurements with a volume as low as 50 µL.
authors.affiliation: Departamento de Física, Universidad de Santiago de Chile, Avenida Ecuador 3493, Estación Central, Santiago 9170124, Chile. felipe.aguilarsan@usach.cl.
authors.forename: Felipe Aguilar
authors.initials: FA
authors.lastname: Sandoval
authors.affiliation: Departamento de Física, Universidad de Santiago de Chile, Avenida Ecuador 3493, Estación Central, Santiago 9170124, Chile. manuel.sepulveda@usach.cl.
authors.forename: Manuel
authors.initials: M
authors.lastname: Sepúlveda
authors.affiliation: Laboratoire de Physique, Ecole Normale Supérieure de Lyon, Université de Lyon, CNRS, 46 Allée d'Italie, Lyon F-69007, France. ludovic.bellon@ens-lyon.fr.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Bellon
authors.affiliation: Departamento de Física, Universidad de Santiago de Chile, Avenida Ecuador 3493, Estación Central, Santiago 9170124, Chile. francisco.melo@usach.cl.
authors.forename: Francisco
authors.initials: F
authors.lastname: Melo
mesh_terms: D005990:Glycerol / Q000737:chemistry; D007368:Interferometry / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D013696:Temperature; D014783:Viscosity
chemical_list: D005990:Glycerol
keywords: MEMS; thermal fluctuations; viscosity in liquids