Publications (59) View all
-
Article: Encapsulation of yeast displaying glucose oxidase on their surface in graphene oxide hydrogel scaffolding and its bioactivation.
[show abstract] [hide abstract]
ABSTRACT: Yeast displaying glucose oxidase on their surface were encapsulated in a graphene oxide hydrogel. The ability of the modified yeast to reduce graphene oxide by glucose assimilation while maintaining viability was tested with time and deemed suitable for biofuel cell applications.Chemical Communications 11/2012; · 6.17 Impact Factor -
Article: Hydrogen peroxide induced formation of peroxystannate nanoparticles
[show abstract] [hide abstract]
ABSTRACT: Stable, amorphous potassium peroxystannate nanoparticles of controlled average size—in the range 10–100nm—and of controlled hydrogen peroxide content—in the range of 19–30wt%—were synthesized by hydrogen peroxide induced polymerization in water–potassium hexahydroxostannate solutions. The sol phase and the precipitate were characterized by vibrational spectroscopies, 119Sn NMR, XPS and XRD using crystalline K2Sn(OH)6 and K2Sn(OOH)6 reference materials. This is the first study to show that peroxocoordination induces polymerization of a main group element. 119Sn NMR studies show that peroxotin coordination and polymerization took place already in the hydrogen peroxide–water phase. The high abundance of peroxotin bonds revealed by 119Sn MAS NMR, vibrational spectroscopy, and XPS suggests that the particles are predominantly made of peroxo bridged tin networks. Although the particles are highly stable in the dry phase as well as in alcohol solutions and do not lose hydrogen peroxide upon storage, they release their stored hydrogen peroxide content by exposure to water.Journal of Sol-Gel Science and Technology 05/2012; 50(2):229-240. · 1.63 Impact Factor -
Article: Ammonium and caesium carbonate peroxosolvates: supramolecular networks formed by hydrogen bonds.
[show abstract] [hide abstract]
ABSTRACT: Diammonium carbonate hydrogen peroxide monosolvate, 2NH(4)(+)·CO(3)(2-)·H(2)O(2), (I), and dicaesium carbonate hydrogen peroxide trisolvate, 2Cs(+)·CO(3)(2-)·3H(2)O(2), (II), were crystallized from 98% hydrogen peroxide. In (I), the carbonate anions and peroxide solvent molecules are arranged on twofold axes. The peroxide molecules act as donors in only two hydrogen bonds with carbonate groups, forming chains along the a and c axes. In the structure of (II), there are three independent Cs(+) ions, two of them residing on twofold axes, as are two of the four peroxide molecules, one of which is disordered. Both structures comprise complicated three-dimensional hydrogen-bonded networks.Acta crystallographica. Section C, Crystal structure communications 03/2012; 68(Pt 3):i20-4. · 0.78 Impact Factor -
Article: H-bond network in amino acid cocrystals with H2O or H2O2. The DFT study of serine-H2O and serine-H2O2.
[show abstract] [hide abstract]
ABSTRACT: The structure, IR spectrum, and H-bond network in the serine-H(2)O and serine-H(2)O(2) crystals were studied using DFT computations with periodic boundary conditions. Two different basis sets were used: the all-electron Gaussian-type orbital basis set and the plane wave basis set. Computed frequencies of the IR-active vibrations of the titled crystals are quite different in the range of 10-100 cm(-1). Harmonic approximation fails to reproduce IR active bands in the 2500-2800 frequency region of serine-H(2)O and serine-H(2)O(2). The bands around 2500 and 2700 cm(-1) do exist in the anharmonic IR spectra and are caused by the first overtone of the OH bending vibrations of H(2)O and a combination vibration of the symmetric and asymmetric bendings of H(2)O(2). The quantum-topological analysis of the crystalline electron density enables us to describe quantitatively the H-bond network. It is much more complex in the title crystals than in a serine crystal. Appearance of water leads to an increase of the energy of the amino acid-amino acid interactions, up to ~50 kJ/mol. The energy of the amino acid-water H-bonds is ~30 kJ/mol. The H(2)O/H(2)O(2) substitution does not change the H-bond network; however, the energy of the amino acid-H(2)O(2) contacts increases up to 60 kJ/mol. This is caused by the fact that H(2)O(2) is a much better proton donor than H(2)O in the title crystals.The Journal of Physical Chemistry A 11/2011; 115(46):13657-63. · 2.95 Impact Factor -
Article: Preparation and characterization of mono- and multilayer films of polymerizable 1,2-polybutadiene using the Langmuir-Blodgett technique.
[show abstract] [hide abstract]
ABSTRACT: The essence of this study is to apply the Langmuir-Blodgett (LB) technique for assembling asymmetric membranes. Accordingly, Langmuir films of a (further) polymerizable polymer, 1,2-polybutadiene (1,2-pbd), were studied and transferred onto different solid supports, such as gold, indium tin oxide (ITO), and silicon. The layers were characterized both at the air/water interface as well as on different substrates using numerous methods including cyclic voltammetry, impedance spectroscopy, spectroscopic ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and reflection-absorption Fourier transform infrared spectroscopy. The Langmuir films were stable at the air-water interface as long as they were not exposed to UV irradiation. The LB films formed disorganized layers, which gradually blocked the permeation of different species with increasing the number of deposited layers. The thickness was ca. 4-7 Å per layer. Irradiating the Langmuir films caused their cross-linking at the air-water interface. Furthermore, we took advantage of the reactivity of the double bond of the LB films on the solid supports and graft polymerized acrylic acid on top of the 1,2-pbd layers. This approach is the basis of the formation of an asymmetric membrane that requires different porosity on both of its sides.Langmuir 08/2011; 27(19):11889-98. · 4.19 Impact Factor
