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QUANTIFYING PARTICLE PROPERTIES FROM ION-MOBILITY MEASUREMENTS

dc.contributor.advisorZachariah, Michael R.en_US
dc.contributor.authorLi, Mingdongen_US
dc.date.accessioned2013-02-07T07:02:11Z
dc.date.available2013-02-07T07:02:11Z
dc.date.issued2012en_US
dc.identifier.urihttp://hdl.handle.net/1903/13627
dc.description.abstractNanoparticles have received considerable interest due to the wide variety of potential applications in biomedical, optical, and electronic fields. However, our capabilities for quantitatively charactering these materials, for example in number concentration or shape are limited. The objective of this work is to develop experimentally verified theories to quantify particle properties from aerosol based ion-mobility measurement. The use of aerosol tools is predicated on the idea that these methods offer the best chance for quantification, due to a better understanding of the physics of ion transport in the gas phase. Nevertheless this does not preclude us from using these techniques to characterize particles in liquids as will be show in the first part of this work which resolves problems associated with generating an aerosol from colloidal suspensions. In this dissertation I resolve the problem of artificial "droplet induced aggregation" during electrospray which can corrupt the eventual determination of particle size. I develop an experimentally verified statistical based model, to determine and correct this undesired artifact. Furthermore, I have found that this nominally undesired artifact can be used in a beneficial way that allows one to determine the absolute number concentration of nanoparticles in solution, without the need for calibration particles. Mobility is one of the most important and fundamental properties of a particle. However most particle characterization approaches interpret the results of mobility measurement in the context of spherical particle transport. I have undertaken to systematically explore the mobility properties of non-spherical particles. In this dissertation I develop a theory to quantify the effect of orientation on the mobility and the dynamic shape factor of charged axially symmetric particles in an electric field. The experimental results of well-defined doublets of NIST traceable size standard 127nm, 150nm, 200nm and 240nm PSL spheres are shown to be in excellent agreement with the expected values based on my theory. More general new theories of the mobility of nonspherical particles are also proposed and compared with current theories. I also propose a new instrument, a pulsed differential mobility analyzer (PDMA), to obtain shape information by measuring the electrical mobility under different electric fields.en_US
dc.titleQUANTIFYING PARTICLE PROPERTIES FROM ION-MOBILITY MEASUREMENTSen_US
dc.typeDissertationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentChemical Physicsen_US
dc.subject.pqcontrolledAnalytical chemistryen_US
dc.subject.pqcontrolledChemistryen_US
dc.subject.pqcontrolledNanotechnologyen_US
dc.subject.pquncontrolledaerosolen_US
dc.subject.pquncontrolledDMAen_US
dc.subject.pquncontrolledelectrosprayen_US
dc.subject.pquncontrolledmobilityen_US
dc.subject.pquncontrollednanoparticleen_US
dc.subject.pquncontrollednon-spherical particleen_US


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