Design, fabrication, and testing of a MEMS rheometer

What is it about?

The design, fabrication and experimental analysis of a piezoelectrically actuated micro squeeze flow rheometer is presented. Being only 30x30x0.5mm in size, the micro rheometer is sensitive to very small volumes of the order of 1-10nL of liquid and light enough to operate at frequencies in the kHz regime, an order of magnitude higher than normally attainable with conventional cone and plate rheometry. Initial experiments show that the response of the rheometer is dependent on the viscoelasticity of the fluid being tested. The prototype was used to measure the moduli of poly(dimethylsiloxane) (PDMS) of viscosity 10Pas, a non-volatile viscoelastic fluid, over the frequency range of 10-1000Hz. Results show good agreement between with the moduli measured using conventional rheometry up to 100Hz and with values extrapolated up to 1kHz.

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