Atomic force microscopy of thin triblock copolymer films

Berg, R. van den; Groot, H. de; Dijk, Marc A. van; Denley, D.

doi:10.1016/s0032-3861(05)80056-4

Cited by 49 publications

(32 citation statements)

References 6 publications

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“…[14] In addition, it presents a morphology characterized by the two block components segregated into different phases with a typical microdomain structure. [15] This feature may result in a selective location of the polyaniline in one of the two phases of the SBS block copolymer, giving rise to an insulator-conductor transition with lower percolation threshold.…”

Section: Full Papermentioning

confidence: 99%

Effect of Blend Preparation on Electrical, Dielectric, and Dynamical‐Mechanical Properties of Conducting Polymer Blend: SBS Triblock Copolymer/Polyaniline

Soares¹,

Leyva²

2007

Macro Materials & Eng

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Conducting polymer blends based on styrene–butadiene–styrene (SBS) triblock copolymer and polyaniline doped with dodecylbenzene sulfonic acid (Pani.DBSA) were prepared by different procedures: mechanical mixing (MM) and ‘in situ’ polymerization (ISP) methods. The ISP blends exhibited higher levels of electrical conductivity, as compared to MM blends. The scanning electron micrographs of the ISP blend were characterized by the presence of microtubules, which favored the formation of the conducting pathways inside the SBS matrix. From dynamic mechanical and dielectric analysis, it was possible to suggest a higher interaction degree of the polyaniline with the polystyrene phase of the block copolymer. Blends prepared by ISP method displayed also higher dielectric constant and higher dielectric loss factor than blends prepared by MM method.magnified image

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Section: Full Papermentioning

confidence: 99%

Effect of Blend Preparation on Electrical, Dielectric, and Dynamical‐Mechanical Properties of Conducting Polymer Blend: SBS Triblock Copolymer/Polyaniline

Soares¹,

Leyva²

2007

Macro Materials & Eng

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“…The styrene‐butadiene‐styrene (SBS) block copolymer constitutes a very interesting insulating polymer matrix for the development of CPC because of its unique mechanical and morphological characteristics. SBS is considered a heterogeneous system because of the structural incompatibility between polystyrene (PS) and polybutadiene (PBD) segments 13. When CB is dispersed inside the SBS matrix, a preferential interaction of the filler is expected with the PBD phase, as observed in a previous study of PS‐PBD physical blends 7.…”

Section: Introductionmentioning

confidence: 95%

Electric, dielectric, and dynamic mechanical behavior of carbon black/styrene‐butadiene‐styrene composites

Leyva

Barra

Moreira

et al. 2003

J Polym Sci B Polym Phys

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The conductivity of styrene‐butadiene‐styrene block copolymers containing different amounts of extraconductive carbon black (CB) was investigated as a function of the mold temperature. The composites exhibited reduced percolation thresholds (between 1.0 and 2.0 vol % CB). The dynamic mechanical analysis characterization revealed that the glass‐rubber‐transition temperatures of both segments were not affected by the CB addition, although the damping of the polybutadiene phase displayed a progressive drop with an increase in the CB concentration. The normalized curves of tan δ/tan δmax (where tan δ represents the value of the loss tangent at any measurement temperature and tan δmax represents the loss tangent peak value at the corresponding temperature Tmax) versus T/Tmax (where T is the temperature and Tmax is the maximum temperature), corresponding to both polystyrene and polybutadiene phases as well as the activation energy related to the glass‐rubber‐transition process, did not present any significant change with the addition of CB. The dielectric analysis revealed the presence of two relaxation peaks in the composite containing 1.5 vol % CB, the magnitude of which was strongly influenced by the frequency, being attributed to interfacial Maxwell‐Wagner‐Sillars relaxations caused by the presence of different interfaces in the composite. The mechanical properties were not affected by the presence of CB at concentrations of up to 2.5 vol %. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2983–2997, 2003

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“…Studies of change in the microdomain structures under an external field, such as a shear flow or an electric field, are also notable. Exclusively, the lamellar ordering under the oscillatory shear, [8][9][10][11][12][13] under the electric field, 14,15 or in confined geometry ͑in thin films͒ 7, [16][17][18][19][20] has been studied experimentally and by computer simulations.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of morphological transition in Polystyrene–block- polybutadiene–block-polystyrene triblock copolymer melt

Sakurai

Umeda

Taie

et al. 1996

The Journal of Chemical Physics

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The kinetics of morphological transition from cylinders to lamellae was studied using a time-resolved small-angle x-ray scattering (SAXS) technique with synchrotron radiations. The sample examined is a polystyrene–block-polybutadiene–block-polystyrene (SBS) triblock copolymer having a number average molecular weight, Mn=6.31×104 and a volume fraction of polystyrene (PS) blocks, φPS=0.53. We previously reported that this sample formed a nonequilibrium morphology of polybutadiene (PB) cylinders when cast from its methyl ethyl ketone (MEK) solution. MEK is a selective solvent, i.e., good for PS chains but poor for PB chains. The transmission electron microscopy revealed that the PB cylinders transformed into wavy lamellae through coalescence when the samples were annealed at temperatures above the glass transition temperature of PS. It was also revealed that well-ordered lamellae were formed in the fully annealed samples. In order to discuss quantitatively the morphological transition and the subsequent lamellar ordering, we conducted the time-resolved SAXS measurements. Diffraction peaks arising from hexagonally packed cylinders were decreasing while those arising from alternating lamellae were increasing with time. It was found that the temporal change of the integrated intensity of the diffraction peak could not be fitted by a single exponential decay, but could be expressed by an exponential decay of time with β power. The values of β were in the range of 1<β<2. From the resultant decay time, apparent activation energies were further evaluated for coalescing cylinders and for ordering lamellae. These values were approximately in accord with each other, and it can be simply concluded that the kinetics of the morphological transition is governed by the polystyrene matrix phase.

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Atomic force microscopy of thin triblock copolymer films

Cited by 49 publications

References 6 publications

Effect of Blend Preparation on Electrical, Dielectric, and Dynamical‐Mechanical Properties of Conducting Polymer Blend: SBS Triblock Copolymer/Polyaniline

Effect of Blend Preparation on Electrical, Dielectric, and Dynamical‐Mechanical Properties of Conducting Polymer Blend: SBS Triblock Copolymer/Polyaniline

Electric, dielectric, and dynamic mechanical behavior of carbon black/styrene‐butadiene‐styrene composites

Kinetics of morphological transition in Polystyrene–block- polybutadiene–block-polystyrene triblock copolymer melt

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