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dc.contributor.authorAthanasiadis, Athanasiosen
dc.contributor.authorFitzgerald, Clareen
dc.contributor.authorDavidson, Nicholas Men
dc.contributor.authorGiorio, Chiaraen
dc.contributor.authorBotchway, Stanley Wen
dc.contributor.authorWard, Andrew Den
dc.contributor.authorKalberer, Markusen
dc.contributor.authorPope, Francis Den
dc.contributor.authorKuimova, Marina Ken
dc.date.accessioned2016-12-19T14:51:14Z
dc.date.available2016-12-19T14:51:14Z
dc.date.issued2016-11en
dc.identifier.issn1463-9076
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/261644
dc.description.abstractOrganic aerosols (OAs) play important roles in multiple atmospheric processes, including climate change, and can impact human health. The physico-chemical properties of OAs are important for all these processes and can evolve through reactions with various atmospheric components, including oxidants. The dynamic nature of these reactions makes it challenging to obtain a true representation of their composition and surface chemistry. Here we investigate the microscopic viscosity of the model OA composed of squalene, undergoing chemical aging. We employ Fluorescent Lifetime Imaging Microscopy (FLIM) in conjunction with viscosity sensitive probes termed molecular rotors, in order to image the changes in microviscosity in real time during oxidation with ozone and hydroxyl radicals, which are two key oxidising species in the troposphere. We also recorded the Raman spectra of the levitated particles to follow the reactivity during particle ozonolysis. The levitation of droplets was achieved $\textit{via}$ optical trapping that enabled simultaneous levitation and measurement $\textit{via}$ FLIM or Raman spectroscopy and allowed the true aerosol phase to be probed. Our data revealed a very significant increase in viscosity of the levitated squalene droplets upon ozonolysis, following their transformation from the liquid to solid phase that was not observable when the oxidation was carried out on coverslip mounted droplets. FLIM imaging with sub-micron spatial resolution also revealed spatial heterogeneity in the viscosity distribution of oxidised droplets. Overall, a combination of molecular rotors, FLIM and optical trapping is able to provide powerful insights into OA chemistry and the microscopic structure that enables the dynamic monitoring of microscopic viscosity in aerosol particles in their true phase.
dc.description.sponsorshipMKK is thankful to the EPSRC for the Career Acceleration Fellowship (EP/I003983/1). CF thanks NERC for a personal studentship NE/J500070/1. CF and MK were supported by ERC grant 279405. We are thankful to the CLF RAL for a programmed access grant LSF1207 (FLIMOLA).
dc.format.mediumPrinten
dc.languageengen
dc.language.isoenen
dc.publisherRoyal Society of Chemistry
dc.titleDynamic viscosity mapping of the oxidation of squalene aerosol particles.en
dc.typeArticle
prism.endingPage30393
prism.publicationDate2016en
prism.publicationNamePhysical chemistry chemical physics : PCCPen
prism.startingPage30385
prism.volume18en
dc.identifier.doi10.17863/CAM.6854
dcterms.dateAccepted2016-10-12en
rioxxterms.versionofrecord10.1039/c6cp05674aen
rioxxterms.versionAMen
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2016-11en
dc.contributor.orcidGiorio, Chiara [0000-0001-7821-7398]
dc.contributor.orcidKalberer, Markus [0000-0001-8885-6556]
dc.identifier.eissn1463-9084
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idEuropean Research Council (279405)
rioxxterms.freetoread.startdate2017-10-12


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