scholarly journals Self-Association Behavior of Cell Membrane-Inspired Amphiphilic Random Copolymers in Water

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 327 ◽  
Author(s):  
Maho Ohshio ◽  
Kazuhiko Ishihara ◽  
Shin-ichi Yusa
Keyword(s):  
Aqueous Solutions ◽  
Fluorescence Probe ◽  
Nmr Relaxation ◽  
Radical Copolymerization ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Random Copolymers ◽  
Free Radical Copolymerization ◽  
Association Behavior ◽  
Self Association

Water-soluble and amphiphilic random copolymers (P(MPC/DMAx)) composed of hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) and hydrophobic n-dodecyl methacrylate (DMA) were prepared via reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization. The compositions of DMA unit (x) in the copolymer were in the range of 0 to 38 unit mol %. The degree of polymerization of P(MPC/DMAx) was adjusted to about 200. Since the monomer reactivity ratios of MPC and DMA are 1.01 and 1.00, respectively, ideal free radical copolymerization occurred. In aqueous solutions, interpolymer aggregation occurred due to the hydrophobic pendant n-dodecyl groups. The aggregation number (Nagg) increased with an increasing x. The mobilities of the DMA and MPC pendant groups in aqueous solutions were restricted, as confirmed by 1H NMR relaxation time measurements, because a part of the MPC units were trapped in the hydrophobic microdomain formed from the pendant n-dodecyl groups. The polarity of the hydrophobic microdomain formed from P(MPC/DMA38) in water was similar to that of ethyl acetate according to fluorescence probe experiments. No specific interactions were found in water between P(MPC/DMAx) and bovine serum albumin because the surface of the interpolymer aggregates contained only hydrophilic MPC units.

scholarly journals Association Behavior of Amphiphilic ABA Triblock Copolymer Composed of Poly(2-methoxyethyl acrylate) (A) and Poly(ethylene oxide) (B) in Aqueous Solution

2021 ◽  
Author(s):  
Yoko Mizoue ◽  
Kazutoshi Haraguchi ◽  
Shin-ichi Yusa
Keyword(s):  
Ethylene Oxide ◽  
Fluorescence Probe ◽  
Blood Compatibility ◽  
Degree Of Polymerization ◽  
Light Scattering Intensity ◽  
Association Behavior ◽  
Poly Ethylene Oxide ◽  
Similar Appearance ◽  
Single Flower ◽  
Poly Ethylene

Poly(2-methoxyethyl acrylate) (PMEA) and poly(ethylene oxide) (PEO) have protein-antifouling properties and blood compatibility. ABA triblock copolymers (PMEAn-PEO11340-PMEAn (MEOMn)) were prepared using single-electron transfer-living radical polymerization (SET-LRP) using a bi-functional PEO macroinitiator. Two types of MEOMn composed of PMEA blocks with a degree of polymerization (DP = n) of 85 and 777 were prepared using the same PEO macroinitiator. MEOMn formed flower micelles with a hydrophobic PMEA (A) core and hydrophilic PEO (B) loop shells in diluted water with a similar appearance to petals. The hydrodynamic radii of MEOM85 and MEOM777 were 151 and 108 nm, respectively. The PMEA block with a large DP formed a tightly packed core. The aggregation number (Nagg) of the PMEA block in a single flower micelle for MEOM85 and MEOM777 was 156 and 164, respectively, which were estimated using a light scat-tering technique. The critical micelle concentrations (CMCs) for MEOM85 and MEOM777 were 0.01 and 0.002 g/L, respectively, as determined by the light scattering intensity and fluorescence probe techniques. The size, Nagg, and CMC for MEOM85 and MEOM777 were almost the same inde-pendent of hydrophobic DP of the PMEA block.

COMPARISON OF BARLEY GUMS ISOLATED BY VARIOUS PROCEDURES

1953 ◽  
Vol 31 (7) ◽  
pp. 653-664 ◽  
Author(s):  
W. O. S. Meredith ◽  
T. A. Watts ◽  
J. A. Anderson
Keyword(s):  
Aqueous Solutions ◽  
Molecular Complex ◽  
Alkali Treatment ◽  
Molecular Size ◽  
Degree Of Polymerization ◽  
Aqueous Extraction ◽  
Water Soluble ◽  
Free Sugars ◽  
Enzyme Systems ◽  
Insoluble Form

A barley gum that is believed to be the undegraded, water-soluble, nonstarch polysaccharide of the grain has been isolated. Aqueous solutions of this gum are extremely viscous and are stable. Enzymes that degrade gum during simple aqueous extraction were inactivated first by refluxing barley grist in boiling 85% alcohol followed by extraction of the dried grist with a 1% solution of papain. Gums of lower degree of polymerization, as judged by viscosity measurements, were obtained by aqueous extraction and acid treatments. Two enzyme systems that degrade gums are thought to be present in barley. One (which is inactivated by alcohol) degrades the initially soluble gum and brings an initially insoluble form into solution. The second system (which is inactivated by papain) accompanies and degrades the initially soluble gum during aqueous extraction or in aqueous solutions of the preparation. The purest gum contains only 0.1% nitrogen, and this may be part of the molecular complex. Mild, cold, alkali treatment of this gum reduces molecular size considerably as measured by viscosity of solutions. "X"-enzyme isolated from a bacterial source cleaves the gum into two oligosaccharides of glucose and a component containing D-glucose, L-arabinose, D-xylose, and D-galactose. No free sugars are produced.

scholarly journals EXTRACTION AND REEXTRACTION OF HISTIDINE AND RIBOFLAVIN BY N-VINYLCAPROLACTAME COPOLYMERS WITH 1-VINYL- AND 1-METHACRYLOYL-3,5-DIMETHYLPYROZOLE

2018 ◽  
Vol 59 (7) ◽  
pp. 55
Author(s):  
Maria S. Lavlinskaya ◽  
Gennadiy V. Shatalov ◽  
Nadezhda Ya. Mokshina ◽  
Oksana A. Pakhomova ◽  
Vyacheslav A. Kuznetsov
Keyword(s):  
Free Radical ◽  
Uv Spectroscopy ◽  
Aqueous Media ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Solution Temperature ◽  
Free Radical Copolymerization ◽  
Critical Solution Temperature ◽  
Two Phases ◽  
Degree Of Extraction

Copolymers of N-vinylcaprolactam (VC) with 1-vinyl-3,5-dimethylpyrazole (VDMP) and 1-methacryloyl-3,5-dimethylpyrazole (MDMP) were synthesized by free radical copolymerization  in dioxane with azodiisobutironitrole as initiator. Both water-soluble and water-insoluble copolymers were obtained. The copolymers compositions were determined by FTIR and UV-spectroscopy. The copolymerization constants were calculated and they were: for VC (М1)–VDMP, r1 = 0.65 ± 0.03, r2 = 0.43 ± 0.03; for VC (М1)–MDMP, r1 = 0.79 ± 0.04, r2 = 0.21 ± 0.02. These values show that VC (М1) exhibits somewhat higher activity compared to М2 and that the tendency toward alternation of comonomer units is more pronounced in VC–MDMP copolymers (r1r2 = 0.17) compared to VC–VDMP copolymers (r1r2 = 0.27). It was found that VC–VDMP copolymers are water-soluble at VC content higher than 75 mol %, and VC–MDMP copolymers at VC content higher than 88 mol %. The water-soluble copolymers based on VC have lower critical solution temperature. Their values are in range of 54-69 °C. Two-phases water-salts systems based on synthesized water-soludle thermoresponsive copolymers are proposed for histidine and riboflavin (re)extraction in aqueous media. It was found that extraction systems based on VC-VDMP copolymers are more efficient then VC-MDMP systems. Degree of extraction for both substances in a case of VC-VDMP copolymers achieved 96%. Reextraction carried out by thermoprecipitation of VC (co)polymers. It was shown that reextraction is more efficient at pH 7.6 and its degree achieved 61.7 % for histidine.

scholarly journals New Thermo-Sensitive Hydrogel Based on Copolymer of 2-hydroxyethyl Acrylate and Ethyl Acrylate

2017 ◽  
Vol 19 (1) ◽  
pp. 47
Author(s):  
R.K. Rakhmetullayeva ◽  
A.N. Azhkeyeva ◽  
G.Zh. Yeligbayeva ◽  
Ye.M. Shaikhutdynov ◽  
G.A. Mun ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Ethyl Acrylate ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Copolymer Composition ◽  
Polymer Hydrogels ◽  
Hydrophobic Moiety ◽  
Sensitive Behavior

In this work firstly the thermo-sensitive polymer hydrogels were obtained by three-dimensional radical copolymerization of water-soluble HEA and hydrophobic monomer ethyl acrylate (EA) in the presence of crosslinking agent N,N’-methylenebisacrylamide (BAA). The hydrogels with certain copolymer compositions showed thermo-sensitive behavior in aqueous solutions. The regularity of complex formation of cross-linked copolymer HEA-EA with anionic and cationic surface-active substances have been studied. The swelling behavior of the hydrogels in cetylpyridinium bromide aqueous solutions was studied. Increased swelling of the hydrogels was observed in the surfactant solutions. The increased swelling was more prominent for the hydrogels with a higher content of the hydrophobic moiety in the copolymer composition and with the higher surfactant concentration. The reason for the observed phenomenon is discussed.

scholarly journals Synthesis of chitosan and N-vinylimidazole graft-copolymers and the properties of their aqueous solutions

2021 ◽  
Vol 23 (4) ◽  
pp. 570-577
Author(s):  
Andrey V. Sorokin ◽  
Marina G. Kholyavka ◽  
Maria S. Lavlinskaya
Keyword(s):  
Aqueous Solutions ◽  
Ammonium Nitrate ◽  
Graft Copolymers ◽  
Gel Permeation Chromatography ◽  
Water Soluble ◽  
Ceric Ammonium Nitrate ◽  
Transmission Electron ◽  
Redox Initiator ◽  
Self Association ◽  
Stimuli Sensitive

The aim of this work is to synthesise chitosan and N-vinylimidazole graft-copolymers of various compositions and to study the properties of their aqueous solutions.Chitosan and N-vinylimidazole graft-copolymers were obtained by solution polymerisation in the presence of a ceric ammonium nitrate redox initiator. The synthesised graft copolymers were characterised by FTIR to determine their compositions and the grafted side chains of poly-N-vinylimidazole were characterised by gel permeation chromatography to determine their molecular wights and polydispersity indices. It was established that the obtained products are characterised by high values of yield and grafting efficiency and low values of the polydispersity index. It was found that when the content of the N-vinylimidazole links is above 57 wt%, the synthesised graft copolymers are water-soluble. Aqueous solutions of the obtained copolymers were characterised using dynamic light scattering, transmission electron microscopy, and laserDoppler microelectrophoresis. The study showed that macromolecules of graft copolymers in aqueous solutions have stimuli-sensitive properties with respect to the medium reaction and at a concentration above 10–2 wt% are characterised by a tendency to self-association forming core-crown aggregates, the geometry of which depends on the molecular masses of the grafted chains. Associates of macromolecules in solutions are characterised by positive values of the electrokinetic potential, the values of which also depend on the medium reaction. Thus, it was found that the ceric ammonium nitrate initiator allows obtaining chitosan and N-vinylimidazole graft-copolymers showing stimuli-sensitive properties in aqueous solutions and prone to self-association at concentrations above 10–2 wt%.

Miniemulsion Polymerization Stabilized by a Well-Defined, Amphiphilic Gradient Poly(styrene-co-acrylic acid) Copolymer

2006 ◽  
Vol 59 (8) ◽  
pp. 544 ◽  
Author(s):  
Catherine Lefay ◽  
Maud Save ◽  
Bernadette Charleux ◽  
Stéphanie Magnet
Keyword(s):  
Particle Size ◽  
Acrylic Acid ◽  
Methyl Methacrylate ◽  
Butyl Acrylate ◽  
Miniemulsion Polymerization ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Free Radical Copolymerization

The nitroxide-mediated controlled free-radical copolymerization of styrene (St) and acrylic acid (AA) was used to synthesize a well-defined poly(St30%-co-AA70%) amphiphilic gradient copolymer. The latter proved to be an efficient stabilizer in the 45 wt.-% solids content, batch miniemulsion polymerizations of St and of mixtures of methyl methacrylate/n-butyl acrylate (35/65 w/w). With 2,2´-azobisisobutyronitrile as an oil-soluble initiator, polystyrene latexes with a very narrow particle distribution were obtained, whereas the water-soluble initiator, potassium persulfate, led to broad, multimodal particle size distributions. Such results were explained by the contribution of two nucleation mechanisms: droplet nucleation and homogeneous nucleation. In contrast, the poly(methyl methacrylate-co-n-butyl acrylate) latexes exhibited larger particle size and narrower particle size distributions with persulfate initiator, than the polystyrene latexes.

Effect of Adding Electrolyte in Cement Paste on the Dispersing Force of Polycarboxylate-Type Superplasticizer

2009 ◽  
Vol 405-406 ◽  
pp. 160-165
Author(s):  
Jun Ying Lai ◽  
Xiao Qian Qian ◽  
Shu Lin Zhan ◽  
Min Hui Fang
Keyword(s):  
Free Radical ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Cement Paste ◽  
Electrolyte Concentration ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Hydrodynamic Diameter ◽  
Free Radical Copolymerization ◽  
Poly Ethylene

A series of water-soluble polycarboxylate-type superplasticizer (PCA) were synthesized by free-radical copolymerization of methyl acrylic acid and methoxy poly(ethylene glyco1) monoacrylate macromonomers in water solutions．Micelles were formed from the resultant PCA with predetermined hydrophobic and hydrophilic blocks in water. The hydrodynamic diameter and size distribution of micelles were determined by dynamic light scattering. The change of the concentration of the electrolyte results directly in the variation of the dispersing force of PCA in cement paste. The dispersing force degrades with increasing electrolyte concentration.

scholarly journals Strong Antimicrobial Activity of Highly Stable Nanocomposite Containing AgNPs Based on Water-Soluble Triazole-Sulfonate Copolymer

Pharmaceutics ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 206
Author(s):  
Alexander Pozdnyakov ◽  
Artem Emel’yanov ◽  
Anastasiya Ivanova ◽  
Nadezhda Kuznetsova ◽  
Tat’yana Semenova ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Chemical Reduction ◽  
Gel Permeation Chromatography ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Morphological Properties ◽  
Hydrodynamic Diameter ◽  
Scanning Calorimetry ◽  
Free Radical Copolymerization ◽  
Strong Antimicrobial Activity

A new hydrophilic polymeric nanocomposite containing AgNPs was synthesized by chemical reduction of metal ions in an aqueous medium in the presence of the copolymer. A new water-soluble copolymer of 1-vinyl-1,2,4-triazole and vinylsulfonic acid sodium salt (poly(VT-co-Na-VSA)) was obtained by free-radical copolymerization and was used as a stabilizing precursor agent. The structural, dimensional, and morphological properties of the nanocomposite were studied by UV–Vis, FTIR, X-ray diffraction, atomic absorption, transmission and scanning electron microscopy, dynamic and electrophoretic light scattering, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. Hydrodynamic diameter of macroclubs for the copolymer was 171 nm, and for the nanocomposite it was 694 nm. Zeta potential for the copolymer was −63.8 mV, and for the nanocomposite it was −70.4 mV. The nanocomposite had strong antimicrobial activity towards Gram-negative and Gram-positive microorganisms: MIC and MBC values were in the range of 0.25–4.0 and 0.5–8.0 μg/mL, respectively.

Synthesis of Water-Soluble Phthalocyanine Derivatives as Models for Petroleum Fractions

2014 ◽  
Vol 926-930 ◽  
pp. 266-269
Author(s):  
Ying Hui Bian ◽  
Shao Tang Xu ◽  
Le Chun Song ◽  
Dao Hong Xia
Keyword(s):  
Absorption Spectra ◽  
Water Soluble ◽  
The Self ◽  
The Novel ◽  
Model Compounds ◽  
Petroleum Fractions ◽  
Association Behavior ◽  
Uv Visible ◽  
Phthalocyanine Derivative ◽  
Self Association

As model compounds to petroleum fractions, the novel phthalocyanine derivative was synthesized and characterized. The self-association behavior of the phthalocyanine derivatives in water-DMSO were investigated by UV-visible (UV-vis) absorption spectra.

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