Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye
Tezin Onay Tarihi: 2014
Öğrenci: ESRA BAĞ
Danışman: İREM EREL GÖKTEPE
Özet: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.