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

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye

Tezin Onay Tarihi: 2016

Öğrenci: CANSU ÜSTOĞLU

Danışman: İREM EREL GÖKTEPE

Özet:

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.