Zirconium oxychloride octahydrate containing hydrogenbonded polymer multilayer films

Download

index.pdf

Date

2014

Author

Bağ, Esra

Metadata

Show full item record

Item Usage Stats

146
views

104
downloads

A facile approach is developed to enhance the pH-stability and controlling destruction kinetics of purely hydrogen-bonded multilayers using ZrOCl2.8H2O. To produce layer-by-layer (LbL) films, coordination complexes of a polyphenol, Tannic Acid (TA) and ZrOCl2.8H2O ((TA+Zr) complexes) were produced and then they were self-assembled at the surface with neutral polymers such as PVCL, PNIPAM and PEO through hydrogen bonding interactions at pH 2. It was shown that incorporation of (TA+Zr) complexes into hydrogen-bonded multilayers provided excellent pH-stability. Stabilization of the films against pH can be explained by the high affinity of Zr4+ for phenolate oxygens of TA assuring the charge balance within the multilayers at increasing pH values. In addition, enhanced association between (TA+Zr) complexes with increasing pH could have also contributed to the stability of multilayers. More importantly, (TA+Zr) complexes allowed controlling kinetics of dissolution. The onset of disintegration of PNIPAM and (TA+Zr) multilayers could be delayed for approximately 10 hours at pH 7.5. In addition, incorporation of (TA+Zr) complexes into multilayers extended the disintegration time period. In contrast to multilayers of PNIPAM and TA which eroded exponentially at pH 7.5, multilayers of PNIPAM and (TA+Zr) complexes disintegrated in a linear fashion in longer periods of time. Such hydrogen-bonded multilayers may be promising for controlled drug release applications from surfaces.

Subject Keywords

Zirconium., Oxychlorides., Hydrogen bonding., Thin films, Multilayered.

URI

http://etd.lib.metu.edu.tr/upload/12616885/index.pdf
https://hdl.handle.net/11511/23325

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Intermolecular heterocyclization of alkynones with 2-mercaptoacetaldehyde under metal-free conditions: synthesis of 2,3-disubstituted thiophenes Vatansever, Erol Can; Kilic, Kubra; Ozer, Merve Sinem; KOZA, GANİ; Menges, Nurettin; Balcı, Metin (Elsevier BV, 2015-09-30) A concise and regioselective approach for the synthesis of 2,3-disubstituted thiophene derivatives has been developed. The synthetic strategy relies on the reaction of an in situ generated 2-mercaptoacetaldehyde with various alkynones. Furthermore, we calculated the energy gap between the HOMO and the LUMO orbitals of all compounds and observed that the introduction of a strong electron-withdrawing group decreased the HOMO-LUMO energy gap.
Intramolecular Heterocyclization of O-Propargylated Aromatic Hydroxyaldehydes as an Expedient Route to Substituted Chromenopyridines under Metal-Free Conditions Keskin, Selbi; Balcı, Metin (2015-02-20) A concise and regioselective approach to the synthesis of chromenopyridine and chromenopyridinone derivatives was developed. The synthetic strategy relies on the O-propargylation of aromatic hydroxyaldehydes followed by reaction with propargylamine. The intramolecular cycloaddition reaction between the alkyne and azadiene, which is formed as an intermediate, furnished the desired skeletons.
Syntheses and characterization of benzimidazole containing polymers: a comparative study on donor unit effect and influence of H-bonding Nurioğlu, Ayda Gökçek; Toppare, Levent Kamil; Department of Chemistry (2013) The first part of this work reports a comparative study on electrochromic properties of two Donor-Acceptor-Donor (DAD) type polymers, namely poly(2-heptyl-4,7-di(thiophen-2-yl)-1H-benzo[d]imidazole) (BImTh) and poly(4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-heptyl-1H-benzo[d]imidazole) (BImEd). DAD type polymers are designed to bear the same acceptor unit, benzimidazole and two different donor units, thiophene and 3,4-ethylenedioxy thiophene (EDOT) to make a comparison based on the donor unit effe...
Direct synthesis of hydrogen storage alloys from their oxides Tan, Serdar; Öztürk, Tayfur; Aydınol, Mehmet Kadri; Department of Metallurgical and Materials Engineering (2011) The aim of this study is the synthesis of hydrogen storage compounds by electrodeoxidation technique which offers an inexpensive and rapid route to synthesize compounds from oxide mixtures. Within the scope of this study, two hydrogen storage compounds, FeTi and Mg2Ni, are aimed to be produced by this technique. In the first part, effect of sintering conditions on synthesis of FeTi was studied. For this purpose, oxide pellets made out of Fe2O3-TiO2 powders were sintered at temperatures between 900 °C – 1300...
Diborane-tetraborane conversion in C-60 vesicles - a theoretical study Türker, Burhan Lemi (2001-08-01) Diborane-tetraborane conversion in a C-60 cage is theoretically considered by using AM1-RHF type semiempirical quantum chemical approach. Molecular orbital characteristics of some endohedrally boron hydride doped C-60 composite systems are investigated and the likeliness of diborane-tetraborane conversion in a C-60 vesicle for the purpose of hydrogen storage is discussed. (C) 2001 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.

Citation Formats

E. Bağ, “Zirconium oxychloride octahydrate containing hydrogenbonded polymer multilayer films,” M.S. - Master of Science, Middle East Technical University, 2014.