Dokument: The Dependence of Polymer Structure and Morphology
on Catalytic Activity
in Molecularly Imprinted Nanogels

Titel:The Dependence of Polymer Structure and Morphology
on Catalytic Activity
in Molecularly Imprinted Nanogels
URL für Lesezeichen:https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=3186
URN (NBN):urn:nbn:de:hbz:061-20050815-001186-0
Kollektion:Dissertationen
Sprache:Englisch
Dokumententyp:Wissenschaftliche Abschlussarbeiten » Dissertation
Medientyp:Text
Autor: Chong, Byong-Oh [Autor]
Dateien:
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Dateien vom 09.02.2007 / geändert 09.02.2007
Beitragender:Prof. Dr. Wulff, Günther [Gutachter]
Stichwörter:nanogel, molecular imprinting, solution polymerization, catalysis, enzyme mimicking, soluble nano-particle, carbonates hydrolysisnanogel, molecular imprinting, solution polymerization, catalysis, enzyme mimicking, soluble nano-particle, carbonates hydrolysis
Dewey Dezimal-Klassifikation:500 Naturwissenschaften und Mathematik » 540 Chemie
Beschreibung:A series of imprinted nanogels was prepared by solution polymerization to catalyze the hydrolysis of diphenylcarbonate (DPC). Diphenylphosphate (DPP) employed as a template molecule and N,N’-diethyl(4-vinylphenyl)amidine (DEVPA) as a binding molecule and these were mixed with an excess of EDMA and MMA. The monomer mixture was highly diluted with cyclopentanone, which was found to be a good solvent for preparation of MMA-based nanogels, and polymerized with AIBN under a variety of conditions.
The resultant nanogels, generally nano-sized particles, were found to give stable solutions in appropriate solvents and, thus, make it possible to carry out the kinetic experiments under homogeneous conditions. Due to their good solubility, it is expected that the nanogels will exhibit good mass transfer properties, one of the known limitations of traditional bulk-polymerized imprinted polymers. Further, this series of nanogels could be characterized by standard techniques available for soluble macromolecules, such as GPC, NMR and membrane osmometry. This relieves the problems associated with the characterization of insoluble materials, such as traditional imprinted polymers.
Moreover, direct proof of the size and shape of an individual nanogel particle was obtained via a special electron microscopy technique. After the characterization of membrane osmometry and potentiometric titration, the number of active sites per 40,000 of absolute number-averaged molecular weight (Mabs) could be calculated to show the relative density of active sites in the nanogels. From these results, it was possible to synthesize an imprinted nanogel which possesses one active site per one individual particle.
This nanogel showed significant catalytic activity in the hydrolysis of DPC and, after modification of polymer structure, displayed even better performance. The most improved result was an approximately 290-fold increase in rate constant compared to that measured in buffer solution, with this nanogel remaining soluble.
A Michaelis-Menten kinetic experiment was also performed, yielding a value of kcat/Km ratio for the imprinted nanogel that was 65.6 times higher than for a control nanogel.
Fachbereich / Einrichtung:Mathematisch- Naturwissenschaftliche Fakultät » WE Chemie
Dokument erstellt am:15.08.2005
Dateien geändert am:12.02.2007
Promotionsantrag am:12.07.2005
Datum der Promotion:12.07.2005
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