Fabrication of functional surfaces: Porphyrin -polyoxometalate films and polymer nanolithography.
Item
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Title
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Fabrication of functional surfaces: Porphyrin -polyoxometalate films and polymer nanolithography.
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Identifier
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AAI3310648
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identifier
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3310648
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Creator
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Bazzan, Giorgio.
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Contributor
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Adviser: Charles Michael Drain
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Date
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2008
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, General | Chemistry, Polymer | Engineering, Materials Science
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Abstract
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Many applications in catalysis, electrochemistry, electro-optics and sensors, require the preparation of ultra thin films or the formation of arrays of nanostructured features on surfaces. Strategies to create thin films using layer-by-layer methods use oppositely charged polymeric polyelectrolytes for both or at least one component to beneficially exploit multitopic electrostatic interactions between the deposited layers with opposite charges. In contrast, the electrostatic deposition of tetracationic 5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphyrin tetra(p-toluenesulfonate) (TMPyP4+) with tetraanionic polyoxometalates such as EuPW11O394- or SiW12O 404- onto charged substrates, such as mica, or polar substrates, such as glass and indium-tin oxide (ITO), demonstrates that the use of polymeric components is not a priori necessary. The use of molecules in sequential dipping approaches requires a careful balance in the interaction energies between the oppositely charged molecules, as demonstrated by the observation that a tetraanionic porphyrin such as 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin does not form layers with TMPyP4+. In the present case, these systems require several rounds of dipping to obtain films of uniform coverage and durability. The thin films deposited onto glass, quartz, ITO, and mica have been characterized by UV-vis, fluorescence, cyclic voltammetry, and AFM microscopy. They are surprisingly robust, since they are not removed by sonication in either organic solvents or 100 mM NaCl.;A new technique to fabricate nano to micro scaled patterns of polymeric materials using a stamping method developed in our lab enables direct fabrication of architectures without employing advanced lithographic tooling or "wet" chemistry for pattern development. The polymer thermal-contact nanotransfer lithography produces nanometer thick polymer patterns on ceramic substrate using commercially available CD-R as stamps. The formation of patterns of functional photonic materials is accomplished by incorporating selected porphyrinoids into commodity polymers and using it in our polymer imprinting lithography technique to create patterns of the doped polymer.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
