Hydrogen-bonded layer-by-layer films of block copolymer micelles with pH-responsive cores

Erel Göktepe, İrem
Zhuk, Aliaksandr
Sukhishvili, Svetlana A.
We report on construction of hydrogen-bonded monolayers and multilayers of micelles of the poly(2-(diethylamino)ethyl methacrylate)-block-poly(N-isopropyl acrylamide) (PDEA-b-PNIPAM) with PNIPAM-corona and polybasic PDEA cores. Films were constructed at pH 7.5 and 25 degrees C to assure the deposition of PDEA-b-PNIPAM in the micellar form. When monolayers of block copolymer micelles (BCMs) were exposed to moderately acidic pH values, micellar cores dissolved, while PDEA-b-PNIPAM remained adsorbed at the surface as unimers. In contrast to reversible micellization of PDEA-b-PNIPAM in solution, micelle-to-unimer transition was irreversible at the surface. Adsorption of a layer of tannic acid (TA) or polyethacrylic acid (PEAA) on top of BCM monolayers inhibited pH-triggered morphological changes within adsorbed BCMs. By taking advantage of the high pK(a) values of TA and PEAA, we were also able to construct multilayers of PDEA-b-PNIPAM micelles through hydrogen bonding interactions between micellar PNIPAM coronas and TA or PEAA. Similar to BCM monolayers coated with TA or PEAA, dissolution of BCMs was also inhibited when incorporated within hydrogen-bonded multilayers. Such inhibition of dissolution is due to enhanced hydrogen bonding interactions between coronal PNIPAM chains and protonated TA molecules or PEAA chains at decreasing pH values restricting the pH-induced conformational changes of the micellar core chains within the adsorbed layer. Films of responsive BCMs are attractive coatings for controlled delivery of functional molecules from surfaces due to a combination of stimuli-response properties with the relatively high loading capacity for functional molecules.


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Erel Göktepe, İrem; Tuncer, Cansel; Butun, Vural; Demirel, A. Levent (2012-01-01)
We report the fabrication of hydrogen-bonded multilayers of micelles of a dually responsive, dicationic block copolymer, poly[2-(N-morpholino)ethyl methacrylate-block-2-(diisopropylamino)ethyl methacrylate] (PMEMA-b-PDPA). By taking advantage of the difference in the hydrophilicity of PMEMA and PDPA blocks, micelles with a PMEMA-corona and a PDPA-core were obtained above pH 6.5 and were assembled layer-by-layer at the surface with tannic acid (TA) at pH 7.4 through hydrogen bonding interactions between morp...
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Hussain, SA; Demirci, S; Ozbayoglu, G (Elsevier BV, 1996-12-25)
There is a growing trend of characterizing coal and coal wastes in order to study the effect of clays present in them during coal washing, Coarse wastes from the Zonguldak Coal Washery, Turkey, were characterized and found to contain kaolinite, illite, and chlorite, These three clays, obtained in almost pure form from various locations in Turkey, have been subjected to X-ray diffraction (XRD) analysis to assess their purity and zeta potential measurements in order to evaluate their properties in terms of th...
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Akbayrak, Merve; Önal, Ahmet Muhtar (Elsevier BV, 2020-07-01)
Herein, we develop various iridium based catalysts using titania, zirconia and ceria as asupporting material(Ir/MO2; M=Ce, Ti, Zr) for hydrogen evolution reaction (HER). To investigate their electrocatalytic activities, glassy carbon electrodes (GCE) were modified by drop casting the catalyst ink without using any binder. Linear sweep voltammetry (LSV) was used to test their electrocatalytic activities in 0.5M H2SO4solution. Among these catalysts, Ir/CeO2was found to exhibit excellent activity and superior ...
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Designing a cost-effective catalyst with high activity and stability for hydrogen evolution reaction (2H(+) + 2e(-) -> H-2) is a big challenge due to increasing demand for energy. Herein, we report the electrocatalytic activity of glassy carbon electrodes with group 4 metal oxides (TiO2, ZrO2, HfO2) supported ruthenium(0) nanoparticles in hydrogen evolution reaction. Electrochemical activity of modified electrodes is investigated by recording linear sweep voltammograms in 0.5 M H2SO4 solution. The results o...
Citation Formats
İ. Erel Göktepe, A. Zhuk, and S. A. Sukhishvili, “Hydrogen-bonded layer-by-layer films of block copolymer micelles with pH-responsive cores,” JOURNAL OF COLLOID AND INTERFACE SCIENCE, pp. 61–69, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/41191.