Redox-active polymer-nanoparticle hybrid materials

2000 ◽  
Vol 72 (1-2) ◽  
pp. 67-72 ◽  
Author(s):  
Keith J. Watson ◽  
Jin Zhu ◽  
SonBinh T. Nguyen ◽  
Chad A. Mirkin
Keyword(s):  
Gold Nanoparticles ◽  
Block Copolymers ◽  
Hybrid Materials ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Electrochemical Studies ◽  
Redox Active ◽  
Gel Permeation ◽  
Current Rectification

Ring-opening metathesis polymerization was used to modify organic soluble gold nanoparticles with redox-active polymers. A gel-permeation chromatography study revealed that each nanoparticle is modified with approximately 11 polymer chains. Electrochemical studies of nanoparticles modified with block copolymers of two different redox-active groups revealed that each monomer is electrochemically accessible, while no current rectification was observed.

Study of block copolymers by gel-permeation chromatography

1982 ◽  
Vol 24 (6) ◽  
pp. 1512-1517 ◽  
Author(s):  
V.V. Nesterov ◽  
V.D. Krasikov ◽  
Ye.V. Chubarova ◽  
B.G. Belen'kii
Keyword(s):  
Block Copolymers ◽  
Gel Permeation Chromatography ◽  
Gel Permeation

Adsorption of monodisperse polybutadienes on carbon black, 3 Displacement of pre-adsorbed molecules by the same polymer. Conformational and molecular weight effects

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Kathy Vuillaume ◽  
Bassel Haidar ◽  
Alain Vidal
Keyword(s):  
Molecular Weight ◽  
Driving Force ◽  
Polymer Concentration ◽  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Gel Permeation ◽  
Conformational Factor ◽  
Before And After ◽  
Displacement Processes

AbstractDisplacement of pre-adsorbed macromolecules by the same polymer, polybutadiene, of the same or of different molecular weight was studied in solution and in the bulk. The effect of polymer concentration on pre-adsorption and displacement processes was determined. Displacement was investigated by gel permeation chromatography and by determination of the amount of bound polymer before and after displacement. A conformational factor was established as a major driving force - besides molecular weight - in the displacement process. Polymer chains adsorbed in flat conformation had the highest adsorption stability and could not be displaced by any other molecular weight of the same polymer.

Investigation of polystyrene-polybutadiene block-copolymers by gel-permeation chromatography and by ozonolysis

1983 ◽  
Vol 25 (12) ◽  
pp. 2986-2995 ◽  
Author(s):  
V.V. Nesterov ◽  
V.D. Krasikov ◽  
V.N. Zgonnik ◽  
Ye.Yu. Melenevskaya ◽  
I.V. Kosheleva ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Gel Permeation Chromatography ◽  
Gel Permeation

scholarly journals End-Group Evaluation of HEMA Initiated Poly(ε-caprolactone) Macromonomers via Enzymatic Ring-Opening Polymerization

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
N. Ugur Kaya ◽  
Y. Avcibasi Guvenilir
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Enzyme Concentration ◽  
Polymer Chains ◽  
Side Reactions ◽  
Initiator Concentration ◽  
Lower Temperature

Poly(ε-caprolactone) (PCL) macromonomers comprising acrylate end-functionality were synthesized via enzymatic ring-opening polymerization (eROP) by utilizing commercially availableCandida antarcticaLipase B (CALB), Novozyme-435. 2-Hydroxyethyl methacrylate (HEMA) was purposed to be the nucleophilic initiator in eROP. The side reactions generated due to the cleavage of ester bonds in HEMA and the growing polymer chains were investigated through altering polymerization period, initiator concentration, temperature, and enzyme concentration.1H NMR evaluations showed that minimum quantities of side reactions were in lower temperatures, initiator concentration, enzyme concentration, and lower monomer conversions. Gel permeation chromatography (GPC) results revealed that lower polydispersity along with number-average molecular weight of end-functionalized PCL macromonomers was obtained depending on higher initiator/monomer ratios, lower temperature (60°C), enzyme concentration (100 mg), and/or polymerization time (2 h). Furthermore, 0.1 HEMA/ε-caprolactone (CL) ratio had higher molecular weight than 0.5 HEMA/CL ratio, while keeping a close value of methacrylate transfer, total methacrylate end-groups, and lower polyester transfer.

Synthesis of 4-vinylbiphenyl–isoprene block copolymers and their characterization by gel-permeation chromatography

1969 ◽  
Vol 7 (1) ◽  
pp. 73-81 ◽  
Author(s):  
J. Heller ◽  
J. F. Schimscheimer ◽  
R. A. Pasternak ◽  
C. B. Kingsley ◽  
J. Moacanin
Keyword(s):  
Block Copolymers ◽  
Gel Permeation Chromatography ◽  
Gel Permeation

Synthesis and characterization of novel organosoluble aromatic copolyimides

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Jintian Yang ◽  
Wei Huang ◽  
Yongfeng Zhou ◽  
Deyue Yan ◽  
Xiaohang Wang
Keyword(s):  
Gel Permeation Chromatography ◽  
Polymer Chains ◽  
Polymerization Process ◽  
Synthesis And Characterization ◽  
Aprotic Solvents ◽  
Solution Casting ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Dipolar Aprotic Solvents

AbstractA series of novel aromatic copolyimides was synthesized from pyromellitic dianhydride with the commercial diamine 4,4’-methylenebisaniline (MBA) and the diamine 4,4’-methylenebis(2-tert-butylaniline) (MBTBA) specially designed by ourselves. The solubility of the copolyimides in conventional solvents decreased with the mole ratio of MBTBA to MBA. When MBTBA/MBA was larger than 8/2, the copolyimides are soluble in low boiling point solvents (such as chloroform and tetrahydrofuran) and can form a transparent, flexible, tough film by solution casting. When MBTBA/MBA was between 7/3 and 5/5, the copolyimides are only soluble in dipolar aprotic solvents (such as dimethylformamide and N-methyl-2-pyrrolidone) and form films, too. The copolyimide was precipitated in m-cresol in the polymerization process when MBTBA/MBA was lower than 5/5. The number-average molecular weights of the soluble copolyimides measured by gel permeation chromatography were larger than 5.0·104 and the polydispersity index was higher than 1.5. Only one glass transition of these copolyimides was detected at around 350°C. The copolyimides did not show appreciable decomposition up to 400°C under air and 550°C under nitrogen, and their thermal stability increased a little with the introduction of MBA into the polymer chains.

Number- and Weight-Average Molecular Weights for Some Proanthocyanidin Polymers (Condensed Tannins)

1986 ◽  
Vol 39 (4) ◽  
pp. 557 ◽  
Author(s):  
LJ Porter
Keyword(s):  
Condensed Tannins ◽  
Laser Light ◽  
Gel Permeation Chromatography ◽  
Laser Light Scattering ◽  
Polymer Chains ◽  
Average Chain Length ◽  
Molecular Weights ◽  
Scattering Measurements ◽  
Gel Permeation ◽  
Derivatives Of

The number-average molecular weights (Mn) and weight-average molecular weights (Mw) for proanthocyanidin polymers (condensed tannins) have been measured by vapour pressure osmometry and low-angle laser light-scattering measurements in methanol. These confirm earlier findings (based on gel permeation chromatography of the peracetate derivatives of these polymers) that they are polydisperse. The results also indicate that the incidence of branching in the polymer chains increases as the average chain length increases.

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