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wizyta

od 2020-09-20

Dr inż. Katarzyna Szcześniak  | 2010-10 <> 2017-10

Doktorant

   CNBM UAM   

  0000-0002-7753-572X     57207966313  

Publikacje                          Seminaria


4.

Cho H.Y., Krys P, Szcześniak K., Schroeder H., Park S., Jurga S., Buback M., Matyjaszewski K.

Synthesis of poly(OEOMA) using macromonomers via "grafting-through" ATRP Atom transfer radical polymerization (ATRP) of oligo(ethylene oxide) methyl ether methacrylate (OEOMA, M-n = 950 or 2080; OEOMA is also termed poly(ethylene glycol) methyl ether methacrylate, PEGMA) macromonomers was investigated as a function of initial monomer concentration, [OEOMA](0), ranging from 50 to 300 mM, and up to 4.5 kbar. Polymerizations were successfully carried out in organic solvents with [OEOMA](0) > 75 mM, whereas with [OEOMA](0) = 50 mM no monomer conversion was observed at ambient pressure, indicating that the macromonomer concentration was below its equilibrium monomer concentration ([M](e)). High pressure reduced [M](e) to a level lower than under ambient pressure, allowing polymerization at [OEOMA](0) = 50 mM up to high monomer conversion and yielding polymers with narrow molecular weight distribution. By varying the targeted degree of polymerization of OEOMA, brushlike or starlike poly(OEOMA) were prepared under both ambient and high pressure.

Macromolecules, 48(18), 6385-6395 (2015)

DOI: 10.1021/acs.macromol.5b01592   (Pobrane:  2018-03-29)


3.

Park S., Cho H.Y., Wegner K.B., Burdynska J., Magenau A.J.D., Paik H.J., Jurga S., Matyjaszewski K.

Star synthesis using macroinitiators via electrochemically mediated atom transfer radical polymerization Electrochemically mediated atom transfer radical polymerization (eATRP) was investigated for synthesis of star polymers using macroinitiators (MIs), achieving high star yield with low Cu catalyst loading (similar to 100 ppm, w/w). The arm first method, using MIs, is one of the most robust procedures for star polymer synthesis. During the polymerization, MIs can react with cross-linkers (divinyl or multivinyl compounds) for initial chain extension followed by the cross-linking reaction. The MIs can be transformed to arms of the star, and the cross-linker can form the star core. In this study, poly(ethylene oxide) (PEO, M-n = 2000) based MIs (PEO MIs) were prepared, and the chain-end functionalities were confirmed by H-1 NMR analysis. The ATRP functionalized PEO MIs were then used for the star synthesis by reacting with ethylene glycol diacrylate cross-linkers. Various experimental conditions were conducted for optimizing star formation, including MI concentration, MI to cross-linker molar ratio, and applied potential (E-app).

Macromolecules, 46(15), 5856-5860 (2013)

DOI: 10.1021/ma401308e


2.

Cho H.Y., Averick S.E., Paredes E., Wegner K., Averick A., Jurga S., Das S.R., Matyjaszewski K.

Star polymers with a cationic core prepared by ATRP for cellular nucleic acids delivery Poly(ethylene glycol) (PEG)-based star polymers with a cationic core were prepared by atom transfer radical polymerization (ATRP) for in vitro nucleic acid (NA) delivery. The star polymers were synthesized by ATRP of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and ethylene glycol dimethacrylate (EGDMA). Star polymers were characterized by gel permeation chromatography, zeta potential, and dynamic light scattering. These star polymers were combined with either plasmid DNA (pDNA) or short interfering RNA (siRNA) duplexes to form polyplexes for intracellular delivery. These polyplexes with either siRNA or pDNA were highly effective in NA delivery, particularly at relatively low star polymer weight or molar ratios, highlighting the importance of NA release in efficient delivery systems.

Biomacromolecules, 14(5), 1262-1267 (2013)

DOI: 10.1021/bm4003199   (Pobrane:  2018-03-22)


1.

Makrocka-Rydzyk M., Wegner K., Szutkowski K., Kozak M., Jurga S., Gao H.

Morphology and NMR self-diffusion in PBA/PEO miktoarm star copolymers Morphology and NMR self-diffusion of two miktoarm star copolymers differing in fraction of poly(n-butyl acrylate) and poly(ethylene oxide) (PBA and PEO) arms were under investigation. Structural characteristics of copolymers was obtained on the basis of Small Angle X-Ray Scattering (SAXS) investigations. The phase separated nanoscale morphology of the miktoarm star copolymer with a high fraction of PEO arms was confirmed by Scanning Probe Microscopy (SPM) studies. The modified Avrami approach was used to obtain the information on the non-isothermal crystallization kinetics of the studied systems. It was observed that the crystallization in the system with a higher content of PBA, occurring at higher undercooling, was characterized by a higher crystallization rate. It was also found that increase in PBA arms fraction leads to the reduction in the size of PEO domains. The activation energy of the crystallization process, estimated with Kissinger's method, is lower for miktoarm star copolymer with higher PBA content, which results from facilitation of the transport of PEO chains in the direction of the growing crystal due to the presence of mobile PBA arms. The self-diffusion studies of miktoarm star copolymers melts, carried out with the Pulsed-Gradient STimulated-Echo (PGSTE) Nuclear Magnetic Resonance (NMR) technique, reveals the existence of at least two types of diffusion mechanisms in these systems.

Zeitschrift für Physikalische Chemie, 226, 1271-1292 (2012)

DOI: 10.1524/zpch.2012.0300   (Pobrane:  2020-10-23)


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