Interdiffusion and Composition Polydispersity in Diblock Copolymers above the Ordering Transition

1995 ◽  
Vol 28 (7) ◽  
pp. 2439-2449 ◽  
Author(s):  
T. Jian ◽  
S. H. Anastasiadis ◽  
A. N. Semenov ◽  
G. Fytas ◽  
G. Fleischer ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Ordering Transition

Chain trapping in diblock copolymers near the ordering transition

2000 ◽  
Vol 51 (1) ◽  
pp. 68-74 ◽  
Author(s):  
S. H Anastasiadis ◽  
F Rittig ◽  
K Chrissopoulou ◽  
G Fleischer ◽  
G Fytas ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Ordering Transition

Intermediate Wavelength Composition Fluctuations in Diblock Copolymers:  Modification of the Diffusive Mode near the Ordering Transition

2002 ◽  
Vol 35 (2) ◽  
pp. 522-528 ◽  
Author(s):  
K. Chrissopoulou ◽  
L. Papoutsakis ◽  
S. H. Anastasiadis ◽  
G. Fytas ◽  
G. Fleischer ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Composition Fluctuations ◽  
Ordering Transition

Dynamics of the Most Probable Composition Fluctuations of “Real” Diblock Copolymers near the Ordering Transition

2001 ◽  
Vol 34 (7) ◽  
pp. 2156-2171 ◽  
Author(s):  
K. Chrissopoulou ◽  
V. A. Pryamitsyn ◽  
S. H. Anastasiadis ◽  
G. Fytas ◽  
A. N. Semenov ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Composition Fluctuations ◽  
Ordering Transition

scholarly journals Diblock Copolymers at Surfaces

1989 ◽  
Vol 171 ◽  
Author(s):  
Peter F. Green ◽  
Thomas M. Christensen ◽  
Thomas P. Russell ◽  
Spiros H. Anastasiadis
Keyword(s):  
Photoelectron Spectroscopy ◽  
Diblock Copolymers ◽  
Secondary Ion Mass Spectrometry ◽  
Microphase Separation ◽  
Mean Field Theory ◽  
Mean Field ◽  
Lower Surface ◽  
Ordering Transition ◽  
Lower Surface Energy ◽  
Number Of Segments

ABSTRACTThe surface properties of symmetric microphase separated diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA) were investigated using X-ray photoelectron spectroscopy (XPS), the specular reflectivity of neutrons and secondary ion mass spectrometry (SIMS). PS, the lower surface energy component, exhibited a preferential affinity for the free surface. For copolymers that are far from the bulk microphase separation transition (MST), the surface consists of a layer of pure PS. When the system is close to the MST the surface is a mixture of PS and PMMA. The PS surface excess can be described bya N-1/2 dependence, where N is the number of segments that comprise the copolymer chain. It is shown that the surface undergoes an ordering transition at a temperature T2 that is above that of the bulk MST. The ordering of the bulk lamellar morphology is induced by an ordering at the surface. This is analogous to the ferromagnetic order observed in systems such as Gd at temperatures above the bulk Curie temperature. The results here are discussed in light of previous work on copolymer surfaces and in light of mean field theory.

scholarly journals Ordering Transition in Salt-Doped Diblock Copolymers

2016 ◽  
Vol 49 (9) ◽  
pp. 3630-3638 ◽  
Author(s):  
Jian Qin ◽  
Juan J. de Pablo
Keyword(s):  
Diblock Copolymers ◽  
Ordering Transition

The Effect of Hydrostatic Pressure on the Lower Critical Ordering Transition in Diblock Copolymers

1998 ◽  
Vol 31 (19) ◽  
pp. 6493-6498 ◽  
Author(s):  
M. Pollard ◽  
T. P. Russell ◽  
A. V. Ruzette ◽  
A. M. Mayes ◽  
Y. Gallot
Keyword(s):  
Hydrostatic Pressure ◽  
Diblock Copolymers ◽  
Ordering Transition ◽  
Effect Of Hydrostatic Pressure

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.

Equilibrium emulsification of polymer blends by diblock copolymers

1990 ◽  
Vol 51 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Zhen-Gang Wang ◽  
S.A. Safran
Keyword(s):  
Polymer Blends ◽  
Diblock Copolymers
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