Surface segregation of conformationally asymmetric polymer blends

Stepanow, S.; Fedorenko, Andrei A.

doi:10.1103/physreve.73.031801

Cited by 4 publications

(14 citation statements)

References 36 publications

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“…Surface energy of components is generally one of responsible factors for surface segregation in polymer mixtures?• 10 In short, when polymers A and B with lower and higher surface energies, respectively, are mixed, the surface will be covered with the polymer A to minimize the free energy of the system. In addition, chain length is also one of responsible factors for surface segregation; a shorter chain component is partitioned to 231 the surface.U- 16 This has been explained in terms of conformation entropy and/or chain end segregation at the surface. Since surface chains are compressed along the direction normal to the surface, 17…”

Section: Introductionmentioning

confidence: 99%

Interfacial Segregation of Hyper-branched Polystyrene in Mixtures of Linear Component

Atarashi¹,

Ariura²,

Akabori³

et al. 2007

Trans. Mat. Res. Soc. Japan

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To study an effect of polymer architecture on surface segregation in polymer mixtures, concentration profile in films composed of hyper-branched polystyrene (HBPS) and deuterated linear polystyrene was examined along the direction normal to the surface by dynamic secondary ion mass spectroscopy. HBPS with two different end groups such as hydrogen and dithiocarbamate (HBPS-H and HBPS-DC) were used. While HBPS-H was preferentially segregated at both surface and substrate interface, HBPS-DC was partitioned only to the substrate interface. These results can be explained in terms of conformational entropic penalty and chain end localization at the surface.

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Section: Introductionmentioning

confidence: 99%

Interfacial Segregation of Hyper-branched Polystyrene in Mixtures of Linear Component

Atarashi¹,

Ariura²,

Akabori³

et al. 2007

Trans. Mat. Res. Soc. Japan

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“…which is often used to describe the behavior of confined incompressible block copolymer melts [26,27], we get α 2 m,n = s 2 m,n /R 2 , where s m,n are the locations of extrema of the Bessel function J m (x) numerated in ascending order.…”

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confidence: 99%

“…In fact, it is sufficient to take into account only the modes {(1, 1), (2, 1)}, which would start to grow early than the coaxial mode (0, 2) in the absence of any preferential adsorption. The resulting phase diagrams within the interval (27) are shown in fig. 2.…”

mentioning

confidence: 99%

“…which is often used to describe the behavior of confined incompressible block copolymer melts [26,27], we get α 3. Substituting eqs (4) into (2) we get…”

mentioning

confidence: 99%

“…Obviously, the term (26) affects the modes (0, n) with n high enough to be of the type (11) and thus favors the coaxial morphologies. Say, the mode (0,2) is dominant in the narrow capillaries satisfying the inequality ρ < s 0,2 = 3.832 (27) if |τ | is not too big. If τ → −∞ the mode (0, 1) becomes dominant since it has the smallest quantitative value of the reduced forth vertex.…”

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Helical, angular and radial ordering in narrow capillaries

Erukhimovich

Johner

2007

Europhys. Lett.

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Abstract. -To enlighten the nature of the order-disorder and order-order transitions in block copolymer melts confined in narrow capillaries we analyze peculiarities of the conventional Landau weak crystallization theory of systems confined to cylindrical geometry. This phenomenological approach provides a quantitative classification of the cylindrical ordered morphologies by expansion of the order parameter spatial distribution into the eigenfunctions of the Laplace operator. The symmetry of the resulting ordered morphologies is shown to strongly depend both on the boundary conditions (wall preference) and dimensionless parameter q * R, where R is the cylinder radius and q * is the wave number of the critical order parameter fluctuations, which determine the bulk ordering of the system under consideration. In particular, occurrence of the helical morphologies is a rather general consequence of the imposed cylindrical symmetry for narrow enough capillaries. We discuss also the ODT and OOT involving some other simplest morphologies. The presented results are relevant also to other ordering systems as charge-density waves appearing under addition of an ionic solute to a solvent in its critical region, weakly charged polyelectrolyte solutions in poor solvent, microemulsions etc.Introduction. -During the last years there has been large interest in the behavior of block copolymer (basically diblock copolymer) melts confined in narrow capillaries, which were studied both experimentally [1-6] and via computer simulation [7][8][9] as well as by numerical calculations within the self-consistent field theory [1,10,11]. The most characteristic of these morphologies are lamellae ordered normal to the cylinder axis z (slab morphology [10] ) and coaxial shells or multiwall morphologies [7,10] as well as various helices [1,8,9], the morphologies' symmetry being strongly depended on the ratio of the gyration radius R G of the diblock macromolecules under consideration and the radius R of the cylinder the macromolecules are confined to. However, some important issues have not been addressed yet. In particular, the various morphologies (up to 20 in ref [11] and up to 30 in ref [9]) are distinguished only visually by their snapshots and no attempts to relate them to a quantitative order parameter are made until now. Meanwhile, without a quantitative definition of an order parameter and, accordingly, finding the quantitative change of such an order parameter at the phase transitions

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Surface Segregation in Athermal Polymer Blends Due to Conformational Asymmetry

Spencer

Matsen

2021

Macromolecules

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Monte Carlo simulations are used to investigate the surfaces of athermal blends of stiff and flexible polymers as the bending modulus of the stiff polymers, κ, is increased from zero to the point where the bulk undergoes an isotropic−nematic transition. For hard walls characteristic of polymer/solid surfaces, the flexible polymers generally segregate to the surface. However, just prior to the bulk transition, a surface transition occurs where a thin nematic layer rich in stiff polymers forms next to the wall. This appears to be followed by a second surface transition where the degree of order abruptly increases, which, in turn, causes a rapid thickening of the nematic layer that nucleates the bulk nematic phase. For soft boundaries representative of polymer/air surfaces, a thin layer rich in stiff polymers but without nematic order forms on the outer edge of the surface with a more significant layer rich in flexible polymers beneath. In this case, the surface transitions are lost and the qualitative behavior remains unchanged as κ increases.

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Surface segregation of conformationally asymmetric polymer blends

Cited by 4 publications

References 36 publications

Interfacial Segregation of Hyper-branched Polystyrene in Mixtures of Linear Component

Interfacial Segregation of Hyper-branched Polystyrene in Mixtures of Linear Component

Helical, angular and radial ordering in narrow capillaries

Surface Segregation in Athermal Polymer Blends Due to Conformational Asymmetry

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