Multilayers of block copolymer micelles with cores exhibiting upper critical solution temperature

Üstoğlu, Cansu
Stimuli-responsive films are promising materials to release functional molecules from surfaces. Layer-by-layer (LbL) is a practical and easy technique to construct stimuli responsive thin films. Thickness and composition of the films can be precisely controlled using this technique. Temperature-responsive (thermo-responsive) polymers are one of the most extensively studied polymers in the construction of stimuli responsive LbL films due to relatively easy control of temperature than the other stimulus. The study presented in this thesis reports on preparation of block copolymer micelles (BCMs) with cores exhibiting upper critical solution temperature (UCST)-type phase behaviour at physiological pH and using such BCMs as building blocks to construct LbL films which can be erased from the surface with increasing temperature. P2VP blocks of P2VP-b-PEO was partially quaternized to obtain permanent positive charge on P2VP. Micellization was induced in the presence of multivalent salt ions, K3Fe(CN)6, via electrostatic interactions among the positively charged P2VP block and multivalent salt anions. The concentration of K3Fe(CN)6 and the micellization temperature were highly critical on the UCST values of the micellar cores. LbL films of QP2VP+[Fe(CN)6]3-)-b-PEO micelles were prepared using tannic acid (TA) at pH 7.5. The driving force for multilayer assembly was hydrogen bonding interactions between TA and the PEO-corona of QP2VP+[Fe(CN)6]3-)-b-PEO micelles. Multilayers could be erased from the surface with increasing temperature. This study contributes to the fundamental understanding of the structure-property relationship in hydrogen-bonded multilayers. The results obtained in this study can pave the way to develop multilayer films for controlled release applications from surfaces.  


Gamma-ray spectroscopy and multipolarity measurements of the proton-rich nucleus ⁹ₑRu
Aktaş, Özge; Yılmaz, Osman; Ataç Nyberg, Ayşe; Department of Physics (2013)
Hydrogenated nano/micro-cystalline silicon (nc-/c-Si:H) thin films are the key materials for Si-based thin film solar cell technology. These films have attracted great attention due to their applications in thin film solar cells. Silicon phase transition from amorphous to nano/micro-crystalline phase is an important phenomenon, especially in progress of Si thin film tandem structured solar cells. It is well-accepted fact that the development of deposition phase diagrams allows phase engineering for systema...
Optoelectronic properties of transparent and conducting single-wall carbon nanotube thin films
Fanchini, G; Ünalan, Hüsnü Emrah; Chhowalla, M (AIP Publishing, 2006-05-08)
Optoelectronic characterization of transparent and conducting single-wall carbon nanotube thin films is reported. By eliminating the influence of voids and bundle-bundle interactions within the effective medium theory, we show that the complex dielectric response of the individual nanotube varies with its density in the film. Specifically, the absorption peak assigned to the maximum intensity of pi-pi(*) transitions was found to decrease from E-pi=5.0 eV at low nanotube density to E-pi=4.2 eV at intermediat...
Microporous vanadosilicate films with tailorable V4+/V5+ ratio to achieve enhanced visible-light photocatalysis
Kuzyaka, Duygu; Uzun, Ceren; Yıldız, İlker; Kaya, Murat; Akata Kurç, Burcu (2021-08-01)
This study investigates the changes induced into the photocatalytic activity under solar light irradiation upon changing the structural film properties and tailor the concentration of defects in microporous vanadosilicate AM-6 films. For this purpose, the preparation of AM-6 films with different V4+/V5+ ratios and their utilization as photocatalysts for the decomposition of MB were carried out. Two approaches were used for obtaining AM-6 films with different V4+/V5+ ratios: altering the seed layer coating t...
Flexible organic photovoltaics from zinc oxide nanowires grown on transparent and conducting single walled carbon nanotube thin films
Ünalan, Hüsnü Emrah; Kuo, Daniel; Parekh, Bhavin; Amaratunga, Gehan; Chhowalla, Manish (Royal Society of Chemistry (RSC), 2008-01-01)
The fabrication of flexible organic photovoltaics (OPVs) which utilize transparent and conducting single walled carbon nanotube (SWNT) thin films as current collecting electrodes on plastic substrates in zinc oxide nanowire (ZnO NW)/poly(3-hexylthiophene) (P3HT) bulk heterojunction photovoltaic devices is reported. The bulk heterojunctions for exciton dissociation are created by directly growing ZnO nanowires from solution on the SWNT electrodes and spin coating the P3HT polymer. A maximum OPV power convers...
Dielectric Characterization of Imatinib Resistant K562 Leukemia Cells through Electrorotation with 3-D Electrodes
Bahrieh, G.; Koydemir, H. Ceylan; Erdem, Murat; Ozgur, E.; Gündüz, Ufuk; Külah, Haluk (2013-11-06)
This study reports the use of electrorotation (ER) technique within a micro-fabricated device with 3D electrodes for dielectric characterization of Imatinib-resistant K562 (K562/IMA-0.2) human leukemic cells. The ER devices with 3D quadruple electrodes (30 mu m in height) were used in order to eliminate the fringing field effect on the rotation of cells. To induce the rotational moment on the cells, signals in phase quadrature were applied to the triangular electrodes. The rotation of cells measured at the ...
Citation Formats
C. Üstoğlu, “Multilayers of block copolymer micelles with cores exhibiting upper critical solution temperature,” M.S. - Master of Science, Middle East Technical University, 2016.