scholarly journals Noncentrosymmetric Lamellar Phase in Blends of ABC Triblock and ac Diblock Copolymers

2001 ◽  
Vol 34 (18) ◽  
pp. 6487-6494 ◽  
Author(s):  
Robert A. Wickham ◽  
An-Chang Shi
Keyword(s):  
Diblock Copolymers ◽  
Lamellar Phase

The Effects of Nanoparticles on the Lamellar Phase Separation of Diblock Copolymers

2008 ◽  
Vol 112 (14) ◽  
pp. 4194-4203 ◽  
Author(s):  
Linli He ◽  
Linxi Zhang ◽  
Haojun Liang
Keyword(s):  
Phase Separation ◽  
Diblock Copolymers ◽  
Lamellar Phase

scholarly journals Molecular theory of the tilting transition and computer simulations of the tilted lamellar phase of rod–coil diblock copolymers

2020 ◽  
Vol 152 (18) ◽  
pp. 184906
Author(s):  
M. A. Osipov ◽  
M. V. Gorkunov ◽  
A. V. Berezkin ◽  
A. A. Antonov ◽  
Y. V. Kudryavtsev
Keyword(s):  
Computer Simulations ◽  
Diblock Copolymers ◽  
Lamellar Phase ◽  
Molecular Theory

scholarly journals Lamellar phase solutions for diblock copolymers with nonlocal diffusions

2019 ◽  
Vol 388 ◽  
pp. 22-32
Author(s):  
Hardy Chan ◽  
Masomeh Jamshid Nejad ◽  
Juncheng Wei
Keyword(s):  
Diblock Copolymers ◽  
Lamellar Phase

Effect of polydispersity on the tensile modulus of diblock copolymers in a lamellar phase

2005 ◽  
Vol 123 (12) ◽  
pp. 124906 ◽  
Author(s):  
Ying Jiang ◽  
Rui Huang ◽  
Haojun Liang
Keyword(s):  
Diblock Copolymers ◽  
Tensile Modulus ◽  
Lamellar Phase

scholarly journals Liquid-Crystal Ordering and Microphase Separation in the Lamellar Phase of Rod-Coil-Rod Triblock Copolymers. Molecular Theory and Computer Simulations

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3392
Author(s):  
Mikhail A. Osipov ◽  
Maxim V. Gorkunov ◽  
Alexander A. Antonov ◽  
Anatoly V. Berezkin ◽  
Yaroslav V. Kudryavtsev
Keyword(s):  
Free Energy ◽  
Correlation Functions ◽  
Density Functional ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Triblock Copolymers ◽  
Molecular Model ◽  
Lamellar Phase ◽  
Density Correlation ◽  
Huggins Parameter

A molecular model of the orientationally ordered lamellar phase exhibited by asymmetric rod-coil-rod triblock copolymers has been developed using the density-functional approach and generalizing the molecular-statistical theory of rod-coil diblock copolymers. An approximate expression for the free energy of the lamellar phase has been obtained in terms of the direct correlation functions of the system, the Flory-Huggins parameter and the Maier-Saupe orientational interaction potential between rods. A detailed derivation of several rod-rod and rod-coil density-density correlation functions required to evaluate the free energy is presented. The orientational and translational order parameters of rod and coil segments depending on the temperature and triblock asymmetry have been calculated numerically by direct minimization of the free energy. Different structure and ordering of the lamellar phase at high and low values of the triblock asymmetry is revealed and analyzed in detail. Asymmetric rod-coil-rod triblock copolymers have been simulated using the method of dissipative particle dynamics in the broad range of the Flory-Huggins parameter and for several values of the triblock asymmetry. It has been found that the lamellar phase appears to be the most stable one at strong segregation. The density distribution of the coil segments and the segments of the two different rods have been determined for different values of the segregation strength. The simulations confirm the existence of a weakly ordered lamellar phase predicted by the density-functional theory, in which the short rods separate from the long ones and are characterized by weak positional ordering.

Defect structures and ordering behaviours of diblock copolymers self-assembling on spherical substrates

Soft Matter ◽  
2014 ◽  
Vol 10 (35) ◽  
pp. 6713-6721 ◽  
Author(s):  
Liangshun Zhang ◽  
Liquan Wang ◽  
Jiaping Lin
Keyword(s):  
Block Copolymers ◽  
Diblock Copolymers ◽  
Lamellar Phase ◽  
Defect Structures ◽  
Self Assembling ◽  
Cylindrical Phase

The Landau–Brazovskii theory is employed to explore defect structures and ordering behaviors of block copolymers confined on spherical substrates. Isolated disclinations and scars are formed in the cylindrical phase. The defect structures of hedgehog, spiral and quasi-baseball are produced in the lamellar phase.

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).

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