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Monitoring sessile droplet evaporation on a micromechanical device.


Type

Article

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Authors

Prasad, A 
Lin, AT-H 
Rao, VR 
Seshia, AA 

Abstract

A bulk acoustic mode micro-electro-mechanical dual resonator platform is utilised to study the evaporation of sub-microliter water droplets from the surface of the resonator. An analytical formulation for the observed frequency shift and the measure dependence of resonant frequency on the modes of evaporation which is consistent with the optically derived data. The resonators access only a thin layer of the liquid through shear contact and, hence, the response is not affected by the bulk mass of the droplet to first order. A relationship between the droplet contact area and the elapsed time was established for the evaporation process and is used to derive a value of the diffusion coefficient of water in air that is found to be in reasonable agreement with literature values. This work introduces a new tool for the electro-mechanical monitoring of droplet evaporation with relevance to applications such as biosensing in liquid samples of sub-microliter volumes.

Description

Keywords

Miniaturization

Journal Title

Analyst

Conference Name

Journal ISSN

0003-2654
1364-5528

Volume Title

139

Publisher

Royal Society of Chemistry (RSC)
Sponsorship
Funding from the Royal Society and the Cambridge Trusts is acknowledged.