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Papers by Volodymyr Lobaz

Journal of Surfactants and Detergents, 2014

Nanotechnology, 2015

In this study, water-dispersed thermo-responsive boron nitride nanotubes (BNNTs) were prepared in... more In this study, water-dispersed thermo-responsive boron nitride nanotubes (BNNTs) were prepared in a simple two-step process, where on the first step oligoperoxide was grafted via the interaction of amino groups (defects) of BNNTs with pyromellitic chloroanhydride fragments in oligoperoxide molecules. The second step involves N-isopropylacrylamide (NIPAM) graft polymerization 'from the surface' of oligoperoxide-functionalized BNNTs resulting in poly(N-isopropylacrylamide) (PNIPAM) coating. The pristine and functionalized BNNTs were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, dynamic light scattering, scanning electron microscopy and atomic force microscopy. PNIPAM-functionalized BNNTs exhibit excellent dispersibility in water and possess thermo-responsive properties. The water-dispersion of thermo-responsive PNIPAM-functionalized BNNTs can help their potential use in biomedical applications as 'smart' surfaces, nanotransducers and nanocarriers.

Biomacromolecules, 2015

ABSTRACT A series of model linear copolymers of 2-hydroxyethyl methacrylate (HEMA) and sterically... more ABSTRACT A series of model linear copolymers of 2-hydroxyethyl methacrylate (HEMA) and sterically hindered amine derivative [N-(2,2,6,6-tetramethyl-piperidin-4-yl)methacrylamide, HAS] were synthesized and characterized. Scavenging activities of the copolymers against reactive oxygen species (peroxyl and hydroxyl radicals) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals were determined. It was found that copolymers with medium HAS content (3.5-4.0 mol%) were better scavengers than copolymers with lower and higher HAS content and also than polyHEMA and polyHAS homopolymers and the HAS monomer. Importantly, these copolymers compared favorably even to established low-molecular weight antioxidant standards (BHA, dexpanthenol). Monomer reactivity ratios were determined, and the microstructure of the copolymers was assessed. Subsequently, crosslinked copolymers in the powder and film forms with the optimized HAS content were synthesized. Their scavenging activities against the three types of radicals were determined, revealing that these hydrogels are potent scavengers of reactive oxygen species.

Chemistry - A European Journal, 2015

In the current work, we present the successful functionalization and stabilization of P-25 TiO2 n... more In the current work, we present the successful functionalization and stabilization of P-25 TiO2 nanoparticles by means of N1,N7-bis(3-(4-tert-butyl-pyridium-methyl)phenyl)-4-(3-(3-(4-tert-butyl-pyridinium-methyl)phenylamino)-3-oxopropyl)-4-(3,4-dihydroxybenzamido)heptanediamide tribromide (1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light-scattering, and zeta potential measurements. As a complement to this, the formation of layer-by-layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20-(phenoxyacetic acid)-porphyrin (2) and 5,10,15,20-(4-(2-ethoxycarbonyl)-4-(2-phenoxyacetamido)heptanedioic acid)-porphyrin (3), is documented. To this end, the layer-by-layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several "on-off" cycles of illumination, we derive monochromatic incident photo-to-current conversion efficiencies of around 3 %.

Thin Solid Films, 2014

We focus on thin films from ZnO nanorod dispersions in order to generate a high lateral order and... more We focus on thin films from ZnO nanorod dispersions in order to generate a high lateral order and a dense space filling structure applicable e. g. in printed optoelectronic devices. Highly stable dispersions with a solid content of up to 60 wt.% in ethanol were prepared using trioxadecanoic acid as stabilizer. With the dispersions we prepared thin films on substrates with a 3D-smectic phase in lateral dimension of cm 2 and thicknesses from below 100 nm up to 1 μm. We show how the concentration of the initial solid content is influencing the formation of domains in our films and discuss the self-assembly process into ordered structures.

Pure and Applied Chemistry, 2000

The objective of the present study is development of novel surface-active block, comb-like, and b... more The objective of the present study is development of novel surface-active block, comb-like, and branched copolymers with peroxide-containing chains, as well as derived functional luminescent and magnetic nanoparticles. The main experimental approaches are based on tailored synthesis of the oligoperoxide surfactants of desired structures and derived coordinating complexes of transitional and rare earth elements. Oligoperoxide-based synthesis of luminescent, magnetic, and other functional nanocomposites with controlled size distribution, functionality, reactivity, and biocompatibility is described. Developed methods provide combining the formation of polymeric, metal, and metal-oxide nanoparticles with irreversible modification of their surface by functional fragments capable of radical and other reactions, including binding of physiologically active substances. Novel nanoparticles were studied by chemical, colloidal-chemical, and rheological methods, X-ray diffraction technique, luminescent spectroscopy, and transmission and scanning electronic microscopy. The availability of ditertiary peroxide fragments on the nanoparticle surface provides a possibility of radical grafting functional polymer chains. The developed functional nanoparticles have been used for phagocytosis measurement, as well as markers of pathological cells, antimicrobial remedies, and nanocarriers for targeted drug delivery. magnetic media . Dendrimers are being used as carrier molecules for drug delivery and gene transfer, as well as cell transfection agents , catalysts in homogeneous catalysis, and as scaffolds to accomplish multivalent presentation of ligands with interesting biological applications .

Macromolecular Symposia, 2004

Abstract Main experimental approaches for obtaining polymer, inorganic and hybrid colloidal parti... more Abstract Main experimental approaches for obtaining polymer, inorganic and hybrid colloidal particles as well as the tailored functionalization of their surface by oligoperoxide surfactants (OPS) and metal complexes (OMC) on their basis are discussed in the paper. ...

Journal of Colloid and Interface Science, 2012

The formation of spherical superparamagnetic colloidal aggregates of magnetite nanoparticles by e... more The formation of spherical superparamagnetic colloidal aggregates of magnetite nanoparticles by emulsification of a ferrofluid and subsequent solvent evaporation has been systematically studied. The colloidal aggregates occur as a dense sphere with magnetite nanoparticles randomly packed and preserved particle-particle separation due to chemisorbed oleic acid. The voids between nanoparticles are filled with solvent and free oleic acid. The latter was found to influence the formation of colloidal aggregates and their surface properties. The choice of surfactant, whether low molecular weight or polymeric, was shown to lead to the colloidal aggregates having tailored interfacial behavior. Magnetization measurements at ambient temperature revealed that the magnetite colloidal aggregates preserve the superparamagnetic properties of the starting nanoparticle units and show high saturation magnetization values up to 57 emu/g. The size distribution of magnetite nanoparticle colloidal aggregates produced by such an approach was found to be a function of emulsion droplet breakup-coalescence and stabilization kinetics and therefore is influenced by the emulsification process conditions and concentrations of the emulsion compounds.

2011 13th International Conference on Transparent Optical Networks, 2011

Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by comb... more Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by combining them with thin metal films. In such hybrids the light transport depends on the parameters of the sphere lattice and the topology of the metal film. This approach allows mixing Bloch modes and surface plasmon polariton modes in the total optical response of hybrid architectures. Stronger modification of the hybrid's optical properties was achieved in the case of tighter light confinement.

2011 13th International Conference on Transparent Optical Networks, 2011

Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by comb... more Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by combining them with thin metal films. In such hybrids the light transport depends on the parameters of the sphere lattice and the topology of the metal film. This approach allows mixing Bloch modes and surface plasmon polariton modes in the total optical response of hybrid architectures. Stronger modification of the hybrid's optical properties was achieved in the case of tighter light confinement.

Journal of Surfactants and Detergents, 2014

Nanotechnology, 2015

In this study, water-dispersed thermo-responsive boron nitride nanotubes (BNNTs) were prepared in... more In this study, water-dispersed thermo-responsive boron nitride nanotubes (BNNTs) were prepared in a simple two-step process, where on the first step oligoperoxide was grafted via the interaction of amino groups (defects) of BNNTs with pyromellitic chloroanhydride fragments in oligoperoxide molecules. The second step involves N-isopropylacrylamide (NIPAM) graft polymerization 'from the surface' of oligoperoxide-functionalized BNNTs resulting in poly(N-isopropylacrylamide) (PNIPAM) coating. The pristine and functionalized BNNTs were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, dynamic light scattering, scanning electron microscopy and atomic force microscopy. PNIPAM-functionalized BNNTs exhibit excellent dispersibility in water and possess thermo-responsive properties. The water-dispersion of thermo-responsive PNIPAM-functionalized BNNTs can help their potential use in biomedical applications as 'smart' surfaces, nanotransducers and nanocarriers.

Biomacromolecules, 2015

ABSTRACT A series of model linear copolymers of 2-hydroxyethyl methacrylate (HEMA) and sterically... more ABSTRACT A series of model linear copolymers of 2-hydroxyethyl methacrylate (HEMA) and sterically hindered amine derivative [N-(2,2,6,6-tetramethyl-piperidin-4-yl)methacrylamide, HAS] were synthesized and characterized. Scavenging activities of the copolymers against reactive oxygen species (peroxyl and hydroxyl radicals) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals were determined. It was found that copolymers with medium HAS content (3.5-4.0 mol%) were better scavengers than copolymers with lower and higher HAS content and also than polyHEMA and polyHAS homopolymers and the HAS monomer. Importantly, these copolymers compared favorably even to established low-molecular weight antioxidant standards (BHA, dexpanthenol). Monomer reactivity ratios were determined, and the microstructure of the copolymers was assessed. Subsequently, crosslinked copolymers in the powder and film forms with the optimized HAS content were synthesized. Their scavenging activities against the three types of radicals were determined, revealing that these hydrogels are potent scavengers of reactive oxygen species.

Chemistry - A European Journal, 2015

In the current work, we present the successful functionalization and stabilization of P-25 TiO2 n... more In the current work, we present the successful functionalization and stabilization of P-25 TiO2 nanoparticles by means of N1,N7-bis(3-(4-tert-butyl-pyridium-methyl)phenyl)-4-(3-(3-(4-tert-butyl-pyridinium-methyl)phenylamino)-3-oxopropyl)-4-(3,4-dihydroxybenzamido)heptanediamide tribromide (1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light-scattering, and zeta potential measurements. As a complement to this, the formation of layer-by-layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20-(phenoxyacetic acid)-porphyrin (2) and 5,10,15,20-(4-(2-ethoxycarbonyl)-4-(2-phenoxyacetamido)heptanedioic acid)-porphyrin (3), is documented. To this end, the layer-by-layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several "on-off" cycles of illumination, we derive monochromatic incident photo-to-current conversion efficiencies of around 3 %.

Thin Solid Films, 2014

We focus on thin films from ZnO nanorod dispersions in order to generate a high lateral order and... more We focus on thin films from ZnO nanorod dispersions in order to generate a high lateral order and a dense space filling structure applicable e. g. in printed optoelectronic devices. Highly stable dispersions with a solid content of up to 60 wt.% in ethanol were prepared using trioxadecanoic acid as stabilizer. With the dispersions we prepared thin films on substrates with a 3D-smectic phase in lateral dimension of cm 2 and thicknesses from below 100 nm up to 1 μm. We show how the concentration of the initial solid content is influencing the formation of domains in our films and discuss the self-assembly process into ordered structures.

Pure and Applied Chemistry, 2000

The objective of the present study is development of novel surface-active block, comb-like, and b... more The objective of the present study is development of novel surface-active block, comb-like, and branched copolymers with peroxide-containing chains, as well as derived functional luminescent and magnetic nanoparticles. The main experimental approaches are based on tailored synthesis of the oligoperoxide surfactants of desired structures and derived coordinating complexes of transitional and rare earth elements. Oligoperoxide-based synthesis of luminescent, magnetic, and other functional nanocomposites with controlled size distribution, functionality, reactivity, and biocompatibility is described. Developed methods provide combining the formation of polymeric, metal, and metal-oxide nanoparticles with irreversible modification of their surface by functional fragments capable of radical and other reactions, including binding of physiologically active substances. Novel nanoparticles were studied by chemical, colloidal-chemical, and rheological methods, X-ray diffraction technique, luminescent spectroscopy, and transmission and scanning electronic microscopy. The availability of ditertiary peroxide fragments on the nanoparticle surface provides a possibility of radical grafting functional polymer chains. The developed functional nanoparticles have been used for phagocytosis measurement, as well as markers of pathological cells, antimicrobial remedies, and nanocarriers for targeted drug delivery. magnetic media . Dendrimers are being used as carrier molecules for drug delivery and gene transfer, as well as cell transfection agents , catalysts in homogeneous catalysis, and as scaffolds to accomplish multivalent presentation of ligands with interesting biological applications .

Macromolecular Symposia, 2004

Abstract Main experimental approaches for obtaining polymer, inorganic and hybrid colloidal parti... more Abstract Main experimental approaches for obtaining polymer, inorganic and hybrid colloidal particles as well as the tailored functionalization of their surface by oligoperoxide surfactants (OPS) and metal complexes (OMC) on their basis are discussed in the paper. ...

Journal of Colloid and Interface Science, 2012

The formation of spherical superparamagnetic colloidal aggregates of magnetite nanoparticles by e... more The formation of spherical superparamagnetic colloidal aggregates of magnetite nanoparticles by emulsification of a ferrofluid and subsequent solvent evaporation has been systematically studied. The colloidal aggregates occur as a dense sphere with magnetite nanoparticles randomly packed and preserved particle-particle separation due to chemisorbed oleic acid. The voids between nanoparticles are filled with solvent and free oleic acid. The latter was found to influence the formation of colloidal aggregates and their surface properties. The choice of surfactant, whether low molecular weight or polymeric, was shown to lead to the colloidal aggregates having tailored interfacial behavior. Magnetization measurements at ambient temperature revealed that the magnetite colloidal aggregates preserve the superparamagnetic properties of the starting nanoparticle units and show high saturation magnetization values up to 57 emu/g. The size distribution of magnetite nanoparticle colloidal aggregates produced by such an approach was found to be a function of emulsion droplet breakup-coalescence and stabilization kinetics and therefore is influenced by the emulsification process conditions and concentrations of the emulsion compounds.

2011 13th International Conference on Transparent Optical Networks, 2011

Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by comb... more Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by combining them with thin metal films. In such hybrids the light transport depends on the parameters of the sphere lattice and the topology of the metal film. This approach allows mixing Bloch modes and surface plasmon polariton modes in the total optical response of hybrid architectures. Stronger modification of the hybrid's optical properties was achieved in the case of tighter light confinement.

2011 13th International Conference on Transparent Optical Networks, 2011

Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by comb... more Control on the optical response of 2-dimensional colloidal photonic crystals was achieved by combining them with thin metal films. In such hybrids the light transport depends on the parameters of the sphere lattice and the topology of the metal film. This approach allows mixing Bloch modes and surface plasmon polariton modes in the total optical response of hybrid architectures. Stronger modification of the hybrid's optical properties was achieved in the case of tighter light confinement.