Size-Exclusion Properties of Nanoporous Films Derived from Polystyrene−Poly(methylmethacrylate) Diblock Copolymers Assessed Using Direct Electrochemistry of Ferritin

2009 ◽  
Vol 81 (2) ◽  
pp. 851-855 ◽  
Author(s):  
Yongxin Li ◽  
Takashi Ito
Keyword(s):  
Diblock Copolymers ◽  
Direct Electrochemistry ◽  
Size Exclusion ◽  
Nanoporous Films

scholarly journals Two-dimensional chromatography of complex polymers. 3. Full analysis of polystyrene-poly(methyl methacrylate) diblock copolymers

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Harald Pasch ◽  
Kibret Mequanint ◽  
Adrian Jörg
Keyword(s):  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Diblock Copolymers ◽  
Size Exclusion ◽  
Molecular Heterogeneity ◽  
Two Dimensional ◽  
Poly Methyl Methacrylate ◽  
Mass Distributions ◽  
Exclusion Chromatography ◽  
Complex Polymers

AbstractPoly(styrene-block-methyl methacrylate)s were fully analyzed by liquid chromatography at the critical point of adsorption (LC-CC) and two-dimensional chromatography. Operating at chromatographic conditions corresponding to the critical points of the homopolymers polystyrene and poly(methyl methacrylate), the block lengths distributions for the different blocks of the block copolymers were determined quantitatively. Information on the amounts and molar mass distributions of homopolymers and coupling products that were identified in the samples as by-products was obtained by on-line coupled 2D chromatography. It was shown that a complete picture of the molecular heterogeneity of block copolymers can be obtained only when information from different chromatographic experiments is combined. Size exclusion chromatography alone is inappropriate for evaluating the molecular heterogeneity of such samples.

Synthesis and quaternization of nitroxide-terminated poly(4-vinylpyridine-co-acrylonitrile) macroinitiators and related diblock copolymers

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Lenka Poláková ◽  
Jan Lokaj ◽  
Petr Holler ◽  
Larisa Starovoytova ◽  
Michal Pekárek ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Size Exclusion Chromatography ◽  
Methyl Iodide ◽  
Diblock Copolymers ◽  
Size Exclusion ◽  
Chain Extension ◽  
Ir Spectrometry ◽  
End Groups ◽  
Exclusion Chromatography

AbstractNitroxide-terminated 4VP AN copolymers have been synthesized at 125 oC using an alkoxyamine (MAMA-SG1) as a unimolecular initiator. Their compositions were compared with those published for the conventional radical 4VP-AN copolymerization. To verify the initiation potential of the copolymers containing nitroxyl end groups, they were employed in chain extension with styrene (S). Both the prepared statistic copolymer macroinitiators and related diblock copolymers, poly(4VP-co-AN) and poly(4VP-co-AN)-block-poly(S), respectively, were quaternized with methyl iodide in N,N-dimethylformamide or methanol at ambient temperature. The size-exclusion chromatography and NMR were used for the characterization of the polymers; the completeness of the quaternization was checked by the IR spectrometry.

Highly Ordered Nanoporous Films from Supramolecular Diblock Copolymers with Hydrogen-Bonding Junctions

2015 ◽  
Vol 127 (38) ◽  
pp. 11269-11273
Author(s):  
Damien Montarnal ◽  
Nicolas Delbosc ◽  
Cécile Chamignon ◽  
Marie-Alice Virolleaud ◽  
Yingdong Luo ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Diblock Copolymers ◽  
Nanoporous Films

Mechanical properties and hydrolytic degradation of methoxy poly(ethylene glycol)-b-poly(DL-lactide-coglycolide- co-ε-caprolactone) diblock copolymer films

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Nongnit Morakot ◽  
Jirasak Threeprom ◽  
Yodthong Baimark
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Ethylene Glycol ◽  
Diblock Copolymers ◽  
Hydrolytic Degradation ◽  
Size Exclusion ◽  
Block Length ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Poly Ethylene

AbstractBiodegradable films of methoxy poly(ethylene glycol)-b-poly(DL-lactideco- glycolide-co-ε-caprolactone) diblock copolymers (MPEG-b-PDLLGCL) were prepared by solution casting method. Effects of MPEG block length and DLL:G:CL ratio of the MPEG-b-PDLLGCL films on their mechanical properties and hydrolytic degradation were studied and discussed. It was found that the mechanical properties of films were strongly dependent on glass transition temperatures (Tg) of the diblock copolymers. The hydrolytic degradation was investigated in phosphatebuffered solution at 37°C. The degraded films were characterized using gravimetry (%water uptake and %weight loss), 1H-NMR spectroscopy, differential scanning calorimetry and size exclusion chromatography. The %weight loss of the degraded films increased and molecular weight decreased on increasing the MPEG block length and incorporating the G and CL units, according to their %water uptakes. The MPEG content of the degraded film decreased and the Tg increased with hydrolytic degradation time.

Highly Ordered Nanoporous Films from Supramolecular Diblock Copolymers with Hydrogen-Bonding Junctions

2015 ◽  
Vol 54 (38) ◽  
pp. 11117-11121 ◽  
Author(s):  
Damien Montarnal ◽  
Nicolas Delbosc ◽  
Cécile Chamignon ◽  
Marie-Alice Virolleaud ◽  
Yingdong Luo ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Diblock Copolymers ◽  
Nanoporous Films

Synthesis and thermal properties of poly(vinylcyclohexane)-b-poly(4-vinylpyridine) diblock copolymers prepared via RAFT polymerization

e-Polymers ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 197-203
Author(s):  
Yinghua Qi ◽  
Iryna I. Perepichka ◽  
Zhengji Song ◽  
Sunil K. Varshney
Keyword(s):  
Thermal Properties ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Size Exclusion ◽  
Esterification Reaction ◽  
Scanning Calorimetry ◽  
Raft Agent ◽  
Exclusion Chromatography ◽  
Ft Ir ◽  
Methylpropionic Acid

AbstractA series of novel poly(vinylcyclohexane)-b-poly(4-vinylpyridine) (PVCH-b-P4VP) diblock copolymers have been synthesized through a combination of anionic and RAFT polymerization techniques. Using this approach, end functionalized ω-hydroxy-polystyrene was used to yield ω-hydroxy-PVCH by hydrogenation followed by end-functionalization via an esterification reaction with 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid to yield PVCH-RAFT agent. The crossover propagation from PVCH-RAFT to 4VP displays living character and allowed generating diblock copolymers with well-defined molecular compositions. The characterization of the resulted polymers was performed using 1H nuclear magnetic resonance (NMR) and Fourier-transform infra-red (FT-IR) spectroscopies, size-exclusion chromatography with light-scattering detector (SEC-LS), and the thermal properties were studied using differential scanning calorimetry (DSC).

Morphological behavior of compatibilized ternary blends prepared by mechanical mixing

1993 ◽  
Vol 51 ◽  
pp. 1200-1201
Author(s):  
S.D. Smith ◽  
R.J. Spontak ◽  
D.H. Melik ◽  
S.M. Buehler ◽  
K.M. Kerr ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Diblock Copolymers ◽  
Ternary Blends ◽  
Mechanical Mixing ◽  
Design Considerations ◽  
Covalently Bonded ◽  
Homopolymer Blends ◽  
Emulsifying Agent ◽  
Surface Active ◽  
Low Entropy

When blended together, homopolymers A and B will normally macrophase-separate into relatively large (≫1 μm) A-rich and B-rich phases, between which exists poor interfacial adhesion, due to a low entropy of mixing. The size scale of phase separation in such a blend can be reduced, and the extent of interfacial A-B contact and entanglement enhanced, via addition of an emulsifying agent such as an AB diblock copolymer. Diblock copolymers consist of a long sequence of A monomers covalently bonded to a long sequence of B monomers. These materials are surface-active and decrease interfacial tension between immiscible phases much in the same way as do small-molecule surfactants. Previous studies have clearly demonstrated the utility of block copolymers in compatibilizing homopolymer blends and enhancing blend properties such as fracture toughness. It is now recognized that optimization of emulsified ternary blends relies upon design considerations such as sufficient block penetration into a macrophase (to avoid block slip) and prevention of a copolymer multilayer at the A-B interface (to avoid intralayer failure).

Triply-periodic nanostructures in surfactant, block copolymer, and biomembrane systems, and simulation of TEMs

1993 ◽  
Vol 51 ◽  
pp. 884-885
Author(s):  
David M. Anderson ◽  
Tomas Landh
Keyword(s):  
Liquid Crystalline ◽  
Diblock Copolymers ◽  
Cubic Phase ◽  
List Type ◽  
Interpenetrating Networks ◽  
Triply Periodic ◽  
Wide Range ◽  
Bicontinuous Cubic ◽  
Phase Liquid ◽  
Dividing Surface

First discovered in surfactant-water liquid crystalline systems, so-called ‘bicontinuous cubic phases’ have the property that hydropnilic and lipophilic microdomains form interpenetrating networks conforming to cubic lattices on the scale of nanometers. Later these same structures were found in star diblock copolymers, where the simultaneous continuity of elastomeric and glassy domains gives rise to unique physical properties. Today it is well-established that the symmetry and topology of such a morphology are accurately described by one of several triply-periodic minimal surfaces, and that the interface between hydrophilic and hydrophobic, or immiscible polymer, domains is described by a triply-periodic surface of constant, nonzero mean curvature. One example of such a dividing surface is shown in figure 5.The study of these structures has become of increasing importance in the past five years for two reasons:1)Bicontinuous cubic phase liquid crystals are now being polymerized to create microporous materials with monodispersed pores and readily functionalizable porewalls; figure 3 shows a TEM from a polymerized surfactant / methylmethacrylate / water cubic phase; and2)Compelling evidence has been found that these same morphologies describe biomembrane systems in a wide range of cells.

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