Measuring temperature gradients in evaporating multicomponent alcohol/water droplets.
We demonstrate that temperature gradients can be investigated in evaporating volatile water/alcohol droplets by characterising the volume averaged temperature by laser induced fluorescence and the near-surface temperature by cavity enhanced Raman scattering. In the former technique, the fluorescence spectrum from Rhodamine B can be used to determine the droplet temperature with an accuracy of +/-1 K. The latter technique uses the band width of the OH stretching Raman band to determine the temperature change within the near-surface volume in which whispering gallery modes propagate with an accuracy of +/-4 K. We demonstrate that the temperatures measured with varying evaporation time, buffer gas pressure, droplet size and composition are consistent with the predictions from a quasi-steady theoretical treatment of the evaporation rate and can be used to investigate temperature gradients within evaporating droplets.
Hopkins
Rebecca J
RJ
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
Howle
Chris R
CR
Reid
Jonathan P
JP
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D000431:Ethanol / Q000737:chemistry*; D013696:Temperature; D014835:Volatilization; D014867:Water / Q000737:chemistry*
D014867:Water; D000431:Ethanol