title: Measuring temperature gradients in evaporating multicomponent alcohol/water droplets.
abstract: 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.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Hopkins
authors.forename: Chris R
authors.initials: CR
authors.lastname: Howle
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Reid
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D000431:Ethanol / Q000737:chemistry*; D013696:Temperature; D014835:Volatilization; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D000431:Ethanol