Search results for: Ricardas Makuska

Items from 1 to 20 out of 27 results

article

Synthesis and Properties of Cationic Gradient Brush Copolymers Carrying PEO Side Chains and Catechol Moieties

Medeina Steponaviciute, Vaidas Klimkevicius, Ricardas Makuska

Macromolecular Chemistry and Physics > 222 > 4 > n/a - n/a

Synthesis and study of brush copolymers carrying long PEO side chains and catechol moieties are reported. Kinetics of reversible‐addition‐fragmentation chain‐transfer copolymerization of 2‐(dimethylamino) ethyl methacrylate (DMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEOMEMA) is studied by size exclusion chromatography (SEC) and ¹H NMR spectroscopy, which allow calculating not only...

article

Automated coating procedures to produce poly(ethylene glycol) brushes in fused‐silica capillaries

Nicklas N. Poulsen, Jesper Østergaard, Nickolaj J. Petersen, Kim Daasbjerg, more

Journal of Separation Science > 40 > 3 > 779 - 788

Many bioanalytical methods rely on electrophoretic separation of structurally labile and surface active biomolecules such as proteins and peptides. Often poor separation efficiency is due to surface adsorption processes leading to protein denaturation and surface fouling in the separation channel. Flexible and reliable approaches for preventing unwanted protein adsorption in separation science are...

article

Successive RAFT polymerization of poly(ethylene oxide) methyl ether methacrylates with different length of PEO chains giving diblock brush copolymers

Vaidas Klimkevicius, Ricardas Makuska

European Polymer Journal > 2017 > 86 > C > 94-105

Synthesis of diblock brush copolymers by RAFT polymerization of poly(ethylene oxide) methyl ether methacrylates with different length of PEO chains (PEO_xMEMA, x=5, 9, 19, and 43) is reported. Polymerization products were characterized by SEC with tetra detection array (RI, LS, DP and UV) which enabled to get not only molecular characteristics but also estimate “livingness” of the polymers. Kinetics...

article

Intracellular Delivery and Triggered Release of DNA Using Biodegradable Poly(2‐hydroxypropylene imine)s Containing Cystamine Units

Alma Bockuviene, Kristina Slavuckyte, Ausvydas Vareikis, Sarunas Zigmantas, more

Macromolecular Bioscience > 16 > 10 > 1497 - 1505

Poly(2‐hydroxypropylene imine)s containing segments of cystamine (PHPI‐CA) are synthesized by polycondensation of 1,3‐dibromo‐2‐propanol with a mixture of 1,3‐diamino‐2‐propanol and cystamine. High molecular weight fractions of these polymers are collected by ultrafiltration and characterized by chemical analysis, ¹H and ¹³C‐NMR spectroscopy, size‐exclusion chromatography with triple detection, and...

chapter

Interfacial Properties of Chitosan-PEO Graft Oligomers: Surface Competition with Unmodified Chitosan Oligomers

Andra Dedinaite, Joseph Iruthayaraj, Natalija Gorochovceva, Ricardas Makuska, more

Progress in Colloid and Polymer Science > Characterization of Polymer Surfaces and Thin Films > 124-130

Oligomers of chitosan carrying 45 units long poly(ethylene oxide), PEO, chains grafted to the C-6 position of the sugar units were prepared using a novel synthesis route. The graft density was high, close to one poly(ethylene oxide) chain grafted to each sugar unit of the chitosan oligomer but a small fraction of unreacted chitosan remained in the sample. The molecular weight distribution of the sample...

article

Poly(ethylene glycol) modified poly(2-hydroxypropylene imine) as efficient reagent for siRNA transfection

Alma Bockuviene, Juste Balciunaite, Kristina Slavuckyte, Lolita Zaliauskiene, more

Journal of Polymer Research > 2016 > 23 > 1 > 1-12

MPEG’ylated poly(2-hydroxypropylene imines) were synthesised using 1,3-diamino-2-propanol, 1,3-dibromo-2-propanol and methoxy poly(ethylene glycol) (MPEG, M_n 1000, 2000, 5000). Trying to find conditions favourable for attachment of MPEG chains, MPEG iodide was either added to the initial mixture of the monomers (method A), or was introduced later, at the end of the reaction (method B). MPEG’ylated...

article

Association of anionic surfactant and physisorbed branched brush layers probed by neutron and optical reflectometry

Xiaoyan Liu, Andra Dedinaite, Tommy Nylander, Aleksandra P. Dabkowska, more

Journal of Colloid And Interface Science > 2015 > 440 > Complete > 245-252

Pre-adsorbed branched brush layers were formed on silica surfaces by adsorption of a diblock copolymer consisting of a linear cationic block and an uncharged bottle-brush block. The charge of the silica surface was found to affect the adsorption, with lower amounts of the cationic polyelectrolyte depositing on less charged silica. Cleaning under basic conditions rendered surfaces more negatively charged...

article

Synthesis of densely grafted copolymers with tert-butyl methacrylate/2-(dimethylamino ethyl) methacrylate side chains as precursors for brush polyelectrolytes and polyampholytes

Daniel Gromadzki, Petr Štĕpánek, Ričardas Makuška

Materials Chemistry and Physics > 2013 > 137 > 3 > 709-715

Methacrylate-based densely grafted copolymers were synthesized by atom transfer radical polymerization (ATRP) and activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) techniques. The linear poly(2-(2-bromoisobutyryloxy)ethyl methacrylate) PBIEM prepared by ATRP served as a macroinitiator backbone. The “grafting from” strategy was used to initiate polymerization...

article

Adsorption Characteristics of Stoichiometric and Nonstoichiometric Molecular Polyelectrolyte Complexes on Silicon Oxynitride Surfaces

Alexander Shovsky, Goran Bijelic, Imre Varga, Ričardas Makuška, more

Langmuir > 2011 > 27 > 3 > 1044 - 1050

article

Synthesis by self-condensing AGET ATRP and solution properties of arborescent poly(sodium 2-acrylamido-2-methyl-N-propane sulfonate)

Daniel Gromadzki, Alexey Tereshchenko, Ričardas Makuška

Polymer > 2010 > 51 > 24 > 5680-5687

Randomly branched (arborescent) poly(sodium 2-acrylamido-2-methyl-N-propanesulfonates) (NaPAMPS) were synthesized via self-condensing vinyl polymerization using activators generated by electron transfer atom transfer radical polymerization (AGET ATRP). The controlled self-condensing AGET ATRP of NaAMPS was realized in the presence of 2-(2-bromopropionyloxy)ethyl acrylate (BPEA) as a branching monomer...

article

Efficient Gene Transfection Using Novel Cationic Polymers Poly(hydroxyalkylene imines)

Lolita Zaliauskiene, Ula Bernadisiute, Ausvydas Vareikis, Ricardas Makuska, more

Bioconjugate Chemistry > 2010 > 21 > 9 > 1602 - 1611

article

Protein interactions with bottle-brush polymer layers: Effect of side chain and charge density ratio probed by QCM-D and AFM

Geoffrey Olanya, Esben Thormann, Imre Varga, Ricardas Makuška, more

Journal of Colloid And Interface Science > 2010 > 349 > 1 > 265-274

Silica surfaces were coated with a range of cationic bottle-brush polymers with 45 units long poly(ethylene oxide) side chains, and their efficiency in reducing protein adsorption was probed by QCM-D, reflectometry and AFM. Preadsorbed layers formed by bottle-brush polymers with different side chain to charge ratio was exposed to two proteins with different net charge, lysozyme and BSA. The reduction...

article

Adsorption characteristics of brush polyelectrolytes on silicon oxynitride revealed by dual polarization interferometry

Goran Bijelic, Alexander Shovsky, Imre Varga, Ricardas Makuska, more

Journal of Colloid And Interface Science > 2010 > 348 > 1 > 189-197

Adsorption properties of bottle-brush polyelectrolytes have been investigated using dual polarization interferometry (DPI), which provides real time monitoring of adsorbed layer thickness and refractive index. The adsorption on silicon oxynitride was carried out from aqueous solution with no added inorganic salt, and the adsorbed polyelectrolyte layer was subsequently rinsed with NaCl solutions of...

article

Synthesis of thermally responsive cylindrical molecular brushes via a combination of nitroxide-mediated radical polymerization and “grafting onto” strategy

Daniel Gromadzki, Alexander Jigounov, Petr Štĕpánek, Ričardas Makuška

European Polymer Journal > 2010 > 46 > 4 > 804-813

Loosely grafted amphiphilic molecular brushes consisting of a hydrophobic polystyrene backbone and hydrophilic poly(ethylene glycol) monomethyl ether (MPEG) side chains, PS-MPEG, were synthesized by a novel two step method. In the first step, well-defined linear poly(p-chloromethylstyrene) PCMS with the degree of polymerization DP≈200 and polydispersity index, M _w /M _n =1.4 was prepared...

article

Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) containing macromonomers

Tatjana Krivorotova, Aušvydas Vareikis, Daniel Gromadzki, Miloš Netopilík, more

European Polymer Journal > 2010 > 46 > 3 > 546-556

Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) substituent containing methacrylate macromonomers, PEO ₅ MEMA and PEO ₄₅ MEMA, was studied by the use of ¹ H NMR spectroscopy for an analysis of residual monomers. From the monomer consumption curves, several parameters including monomer conversion, instantaneous copolymer composition and reactivity...

article

N-PEG’ylation of chitosan via “click chemistry” reactions

Ruta Kulbokaite, Gediminas Ciuta, Milos Netopilik, Ricardas Makuska

Reactive and Functional Polymers > 2009 > 69 > 10 > 771-778

N-azidated chitosan was prepared by four different methods: using azidated epichlorohydrin, sodium azide plius sodium nitrite, trifluoromethane sulfonyl azide or imidazole-1-sulfonyl azide hydrochloride. Using the two last reagents, the degree of azidation (DA) of chitosan was up to 40% and 65%, respectively. N-azidated chitosans with DA at about 60% were insoluble in aqueous and common organic solvents...

article

Combination of “living” nitroxide-mediated and photoiniferter-induced “grafting from” free-radical polymerizations: From branched copolymers to unimolecular micelles and microgels

Daniel Gromadzki, Sergey Filippov, Miloš Netopilík, Ričardas Makuška, more

European Polymer Journal > 2009 > 45 > 6 > 1748-1758

We report on solution properties of lightly grafted copolymers composed of polystyrene (PS) backbone (degree of polymerization of PS backbone, Nb=95) and variable length of poly(tert-butyl methacrylate) P(tBuMA) side chains (degree of polymerization of side chains, Nsc=14–222) at fixed number of grafting sites n=11 and polydispersity index (M _w /M _n ) ranging from 1.05 to 2.63. Synthesis...

article

Cationic polyelectrolytes from natural building blocks of chitosan and inulin

Ugne Janciauskaite, Ricardas Makuska

Reactive and Functional Polymers > 2009 > 69 > 5 > 300-305

Novel chitosan-N-inulin graft copolymers with different degree of substitution (DS) of chitosan were synthesized via water-soluble 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide mediated reaction. Chemical structure and composition of the chitosan derivatives was confirmed by chemical analysis, FT-IR, XPS, ¹ H and ¹³ C NMR spectroscopy, and potentiometry. Chitosan–inulin copolymers...

article

Desorption of bottle-brush polyelectrolytes from silica by addition of linear polyelectrolytes studied by QCM-D and reflectometry

Ali Naderi, Geoffrey Olanya, Ričardas Makuška, Per M. Claesson

Journal of Colloid And Interface Science > 2008 > 323 > 2 > 223-228

The possibility of exchanging adsorbed layers of PEO ₄₅ MEMA:METAC-X brush polyelectrolytes (with two different charge densities, 10 and 75 mol%, denoted by X), with poly(MAPTAC), a highly charged linear polyelectrolyte, was investigated by quartz crystal microbalance with dissipation and reflectometry. The studies were conducted on a silica substrate at pH 10, conditions under which only...

article

Interactions between bottle-brush polyelectrolyte layers: Effects of ionic strength and oppositely charged surfactant

Ali Naderi, Ričardas Makuška, Per M. Claesson

Journal of Colloid And Interface Science > 2008 > 323 > 1 > 191-202

Interactions between cationic bottle-brush polyelectrolyte layers adsorbed on mica across salt and oppositely charged surfactant solutions were investigated with the interferometric surface force apparatus, and the results were compared with what is known for similarly charged linear polyelectrolytes. Ellipsometric measurements demonstrated that the bottle-brush polyelectrolytes, which contain 45...

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Search results for: Ricardas Makuska

Synthesis and Properties of Cationic Gradient Brush Copolymers Carrying PEO Side Chains and Catechol Moieties

Automated coating procedures to produce poly(ethylene glycol) brushes in fused‐silica capillaries

Successive RAFT polymerization of poly(ethylene oxide) methyl ether methacrylates with different length of PEO chains giving diblock brush copolymers

Intracellular Delivery and Triggered Release of DNA Using Biodegradable Poly(2‐hydroxypropylene imine)s Containing Cystamine Units

Interfacial Properties of Chitosan-PEO Graft Oligomers: Surface Competition with Unmodified Chitosan Oligomers

Poly(ethylene glycol) modified poly(2-hydroxypropylene imine) as efficient reagent for siRNA transfection

Association of anionic surfactant and physisorbed branched brush layers probed by neutron and optical reflectometry

Synthesis of densely grafted copolymers with tert-butyl methacrylate/2-(dimethylamino ethyl) methacrylate side chains as precursors for brush polyelectrolytes and polyampholytes

Adsorption Characteristics of Stoichiometric and Nonstoichiometric Molecular Polyelectrolyte Complexes on Silicon Oxynitride Surfaces

Synthesis by self-condensing AGET ATRP and solution properties of arborescent poly(sodium 2-acrylamido-2-methyl-N-propane sulfonate)

Efficient Gene Transfection Using Novel Cationic Polymers Poly(hydroxyalkylene imines)

Protein interactions with bottle-brush polymer layers: Effect of side chain and charge density ratio probed by QCM-D and AFM

Adsorption characteristics of brush polyelectrolytes on silicon oxynitride revealed by dual polarization interferometry

Synthesis of thermally responsive cylindrical molecular brushes via a combination of nitroxide-mediated radical polymerization and “grafting onto” strategy

Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) containing macromonomers

N-PEG’ylation of chitosan via “click chemistry” reactions

Combination of “living” nitroxide-mediated and photoiniferter-induced “grafting from” free-radical polymerizations: From branched copolymers to unimolecular micelles and microgels

Cationic polyelectrolytes from natural building blocks of chitosan and inulin

Desorption of bottle-brush polyelectrolytes from silica by addition of linear polyelectrolytes studied by QCM-D and reflectometry

Interactions between bottle-brush polyelectrolyte layers: Effects of ionic strength and oppositely charged surfactant

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