Nanoparticles produced via laser ablation of microparticles

dc.contributor.advisorMullins, C. B.en
dc.contributor.advisorBrock, J. R. (James Rush), 1930-en
dc.creatorHenneke, Dale Edwinen
dc.date.accessioned2011-03-15T20:01:52Zen
dc.date.available2011-03-15T20:01:52Zen
dc.date.issued2001-12en
dc.descriptiontexten
dc.description.abstractSeveral different nanoparticle synthesis techniques exist. One synthesis method uses the laser ablation of microparticles (LAM) entrained in an aerosol technique to produce charged nanoparticles. Here, we discuss nanoparticles made using the LAM process. Since nanoparticles made in this fashion are charged in the ablation process, they are not overly susceptible to agglomeration. The synthesized particles appear to have diameters that are dependant on background pressure, but are relatively insensitive to gas type. Once the particles have been made, they must be collected in a capping solution to prevent agglomeration from occurring. Two distinct methods of collection have been devised. The first collection scheme uses an impactor to remove any large (>300 [nm]) unablated material. The charged nanoparticle aerosol is then supersonically impacted directly into a surfactant capping solution. The suspension is then gathered for subsequent processing. In the second collection method, the charged nature of the nanoparticles is utilized to deflect the aerosol in an electric field. The electric field drives the particles onto a surfactant laden electrode. Size distributions for silver were determined using a transmission electron microscope; the mean particle diameter was found to be 5 [nm]. The collected nanoparticles were found to be flocculated; this can be explained by inadequate coverage of the capping molecule. For this reason, an annealing step to provide better surface coverage of the cap is performed. As the suspensions are heated, the size of the flocculents decreases. The decrease in flocculent size indicates that nanoparticles are leaving the main group and going into suspension.
dc.description.departmentChemical Engineeringen
dc.format.mediumelectronicen
dc.identifier.urihttp://hdl.handle.net/2152/10524en
dc.language.isoengen
dc.rightsCopyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.en
dc.rights.restrictionRestricteden
dc.subjectNanoparticlesen
dc.subjectLaser ablationen
dc.subjectNanoscienceen
dc.titleNanoparticles produced via laser ablation of microparticlesen
thesis.degree.departmentChemical Engineeringen
thesis.degree.disciplineChemical Engineeringen
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen

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