Expansion factor of a part of a polymer chain in a good solvent measured by small-angle neutron scattering

Matsushita, Yushu; Noda, Ichiro; Nagasawa, Mitsuru; Lodge, Timothy P.; Amis, Eric J.; Han, Charles C.

doi:10.1021/ma00139a027

Cited by 27 publications

(21 citation statements)

References 11 publications

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“…For example, the value evaluated for a DP20 solution ( ¢ = 0.111) by the fitting procedure is about 24.6 nm, higher than the value in 8 solvents (17 .1 nm), but close to 23.8 nm in good solvents at infinite dilution. 27 Therefore, we conclude that the fitted results are close to the values at infinite dilution and further speculate that block copolymers in the disordered semidilute re-392 0. 25.---~----.----.---~----.----.--- gion are expanded in common good solvents from the unperturbed dimension by excluded volume effects, similarly to homopolymer solutions in the semidilute region, 28 and also by fluctuation effect existing near ODT.3,s,7 Mayes et al, 29 reported that the concentration dependence of the correlation length of the semidilute block copolymer solution is consistent with the scaling prediction in the semidilute region, whereas the concentration dependence of q* ( (S 2 ) 112 ) is weaker than the prediction.…”

Section: Discussionsupporting

confidence: 67%

“…(S 2 ) 112 evaluated for DP17 in bulk in the disordered states by the fitting procedure are almost constant around 3.3 nm, close to the value of polystyrene with the same degree of polymerization in e solvents (3.1 nm). 27 Almost the same fitting procedure can be used for DP19 and DP20 solutions in the disordered state using the floating base line and peak height as additional fitting parameters. If Leibler's theory is also applicable to these (semidilute) solutions, (S 2 ) 112 can be evaluated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Order-Disorder Transition of Symmetric Poly(styrene-b-2-vinylpyridine) in Bulk and Solution

Takahashi

Kitade

Noda

et al. 1998

Polym J

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ABSTRACT:Order-disorder transitions (ODT) of symmetric poly(styrene-b-2-vinylpyridine) in a common good solvent and bulk were determined by dynamic rheological and small-angle neutron scattering measurements. ODT conditions determined by both methods are consistent with each other and the degree of polymerization dependence of critical volume fraction in solution at almost constant temperature agrees with the theoretical prediction for semidilute solutions. However, semidilute behavior persists to a much higher concentration than for ordinary polymer solutions and the crossover from semidilute to concentrated regimes is not clear. KEY WORDSOrder-Disorder Transition / Symmetric Diblock Copolymers / Poly(styrene-b-2-vinylpyridine) / Small-Angle Neutron Scattering/ Semidilute Region/ Block copolymers exhibit a phase transition between ordered (microphase-separated) and disordered (homogeneous) states under certain conditions. The orderdisorder transitions (ODT) of block copolymers have been extensively studied and the results are summarized in the literature. 1 -8 A brief outline of the results is as follows.Theoretically, the phase diagram for diblock copolymers in bulk was first discussed by the mean-field approach,9 and later modified to include fluctuation effects. 10 According to the theory, the ODT of symmetric diblock copolymers occurs at (xN)ooT= 10.5 +41.0. N-113 ( 1) where x is the Flory-Huggins interaction parameter, N is the number of statistical segments (monomers) per copolymer molecule and (2) is a term for fluctuation correction. Here (S 2 ), Mm p, and NA are the mean square radius of gyration, number-average molecular weight, mass density and Avogadro's number, respectively. It was also predicted that eq 1 and 2 can be applied to block copolymer solutions by appropriate replacement of the parameters. 11 • 12 Experimentally, most studies on ODT have been carried out for polystyrene-polydiene diblock copolymers such as poly(styrene-b-isoprene) (SI) and hydrocarbon diblock copolymers such as poly(ethylenepropylene-b-ethylethylene) in bulk. Several experimental methods to determine ODT have been examined. At present, small-angle X-ray scattering, small-angle neutron scattering (SANS), birefringence measurement and dynamic rheological measurements (DRM) are generally used. 1 -s Recently, we studied the viscoelastic properties of SI diblock copolymer solutions near ODT and reported that t To whom correspondence should be addressed. 388the shear rate dependence of the first normal stress difference changes from first order to second order, after shear-induced alignment of the microdomain structure occurs. 13 Generally speaking, systematic studies on viscoelastic properties, especially those under steady shear flow are much easier in solution than in bulk. Difference in viscoelastic properties of block components may affect the shear-induced alignment. For better understanding of the viscoelastic properties and shearinduced alignment of diblock copolymers near ODT, it is essential to study them both ...

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Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Order-Disorder Transition of Symmetric Poly(styrene-b-2-vinylpyridine) in Bulk and Solution

Takahashi

Kitade

Noda

et al. 1998

Polym J

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“…On the other hand, the ν value for a linear polymer in a good solvent is approximately 3/5, which was obtained from the neutron and light scattering experiments. [4][5][6][7] The ν values from the experiments agree well with those predicted by the theoretical studies [8][9][10] and the simulations, [11][12][13][14][15] where chain trajectories can be described with a self-avoiding walk (SAW), because the chains bear excluded volumes. a) Electronic mail: jiro.suzuki@kek.jp.…”

Section: Introductionsupporting

confidence: 79%

The theta-temperature depression caused by topological effect in ring polymers studied by Monte Carlo simulation

Suzuki¹,

Takano²,

Matsushita³

2011

The Journal of Chemical Physics

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We studied equilibrium conformations of linear and ring polymers in dilute solutions over the wide range of segment number N of up to 2048 with Monte Carlo simulation, and evaluated N dependence of the radii of gyration, R(g), of chains. The polymer molecules treated in this study are assumed to be composed of beads and bonds, and they are put in a three-dimensional face-centered cubic (FCC) lattice. The values of Flory's critical exponent, ν, for linear and ring polymers were estimated from the N dependence of R(g), and the temperatures at which ν reach 1/2 were obtained. Here we define those as Θ-temperatures in this report. The simulation result shows that the Θ-temperature for ring polymers is evidently lower than that of the linear polymers, and the origin of the Θ-temperature depression is discussed. Since R(g) of a ring polymer is smaller than that for a linear polymer at the same N and temperature, the segment density for a ring polymer is increased by the topological effect and the repulsive force between segments of a ring polymer at the Θ-temperature for a linear polymer is stronger. Thus, the origin of the Θ-temperature depression for ring polymers is the repulsive force emphasized by the topological effect of rings.

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“…To explain this finding, we approximate the PS part of each PS-b-PEO molecule as an ellipse with a longer radius of d PS_PREDICTED /2 ≈ 5.5 nm and a shorter radius x. To find the value of x, we equate a volume of such an ellipse with a volume a sphere with the PS gyration radius, 52 R G,PS in a toluene is 10−30% more, 53 so we estimate that R G,PS = 3.8 ± 0.5 nm. Then, we find that x ≈ 3.5 nm, which makes the PS component to be about 1 nm thicker than the PEO cylinder.…”

Section: Application Of Local Heat To Induce Fingerprintmentioning

confidence: 99%

Local Thermomechanical Analysis of a Microphase-Separated Thin Lamellar PS-b-PEO Film

Rice

Mokarian‐Tabari

King³

et al. 2012

Langmuir

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We use atomic force microscopy (AFM) and hot tip AFM (HT-AFM) to thermophysically characterize a 30 nm thick film of poly(styrene-block-ethylene oxide), PS-b-PEO, and to modify its lamellar patterns having spacing of 39 ± 3 nm. AFM tip scans of the polymer film induce either abrasive surface patterns or nanoscale ripples, which depend upon the tip force, temperature, and number of scans. The evolution of the lamellar patterns is explained by the polymer film molecular structure and mode I crack propagation in the polymer combined with the stick-and-slip behavior of the AFM tip. The HT-AFM measurements at various tip-sample temperatures and scanning speeds yield several thermophysical quantities: the PEO melting temperature of 54 ± 12 °C, the PS glass transition temperature of 54 ± 12 °C, the PS-b-PEO specific heat of 3.6 ± 2.7 J g(-1) K(-1), the PEO melting enthalpy of 111 ± 88 J g(-1), and the free energy of Helmholtz for PEO unfolding (and melting) of 10(-20) J nm(-2). These quantities are obtained for PS-b-PEO volumes of 30,000 nm(3), which correspond to 30 ag of the polymer.

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Expansion factor of a part of a polymer chain in a good solvent measured by small-angle neutron scattering

Abstract: mation prior to publication.Registry No. (Butadiene) (homopolymer), 9003-17-2; (butadiene)-(styrene) (copolymer), 9003-55-8.

Cited by 27 publications

References 11 publications

Order-Disorder Transition of Symmetric Poly(styrene-b-2-vinylpyridine) in Bulk and Solution

Order-Disorder Transition of Symmetric Poly(styrene-b-2-vinylpyridine) in Bulk and Solution

The theta-temperature depression caused by topological effect in ring polymers studied by Monte Carlo simulation

Local Thermomechanical Analysis of a Microphase-Separated Thin Lamellar PS-b-PEO Film

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