An innovative optical viscometer using a resonant surface signal

Abstract

The understanding and analyzing of solid particle behavior in a liquid is a challenge in numerous fields and engineering industry as the petroleum or the cosmetic one. It is indeed essential to know the behavior of soft matter process to avoid problems and ensures the product quality. This study presents the viscometer development working on a resonant optical signal principle by measuring the Free Spectral Range (FSR) parameter of a resonant optical mode during nanoparticles (NPs) sedimentation in a liquid which consists of a water/glycerol mixture. The photonic structure is composed of racetracks micro-resonators made of a UV210 polymer fabricated by deep-UV photolithography developed on an oxidized silicon layer to get a Si/SiO 2 bi-layer. The chip is then integrated in an optical bench to track the evolution of the FSR during the complete sedimentation process. The resonant signal analyze established by an adapted signal processing of silica nanoparticles sedimentation in different water/glycerol concentrations allows us to determine stages and velocity rate of the sedimentation process to finally access to their viscosity. At the same time, measures are performed on a commercial mechanical rheometer so as to compare the dynamic evolution of their viscosity and their associated FSR. The plot of those data versus the glycerol concentration in water obviously shows a possible mathematical transformation between viscosity and FSR slope. There is therefore a good agreement between mechanical and resonant optical measures if we consider the dynamic evolution of both curves ; so this work proves the feasibility of an optical viscometer based on resonant signal.

Low temperature PECVD processes for the fabrication of integrated symmetrical resonant UV210 organic/semiconductor structures

“…This significance is attributed to their potential for integration onto microchips, biocompatibility [17], cost-effective production, and straightforward manipulation and relatively simple fabrication processes [18][19][20][21][22]. Recently, polymer micro resonators (MRs) manufactured through deep-UV lithography (DUV) technology allowing the development of sub-wavelength patterns have been used for the study of nano-particles (NPs) sedimentation in both water [23] and water-glycerol mixtures [24]. These resonant devices enable real-time analysis of colloidal systems in diverse solutions, including dark or opaque substances, with applications in energy, biology, and agriculture fields.…”