Interaction between polymers in dilute solutions of two polymers in a single solvent measured by light scattering and the compatibility of polymers

Kratochvı́l, Pavel; Straková, Dagmar; Tuzar, Zdeněk

doi:10.1002/pi.4980090309

Cited by 21 publications

(9 citation statements)

References 5 publications

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“…It shows an evident analogy with that defining the Flory-Huggins free energy of a mixture of two polymers A and B in the absence of a solvent [5,32]. The only difference comes from the fact that, in our case, chains A and B have blobs of size ξ as subunits, and that the segregation parameter is no longer χ but the effective one χ defined by (14). Of course, these two parameters coincide in the limit ca d → 1 (a is the Kuhn statistical segment and d the space dimensionality).…”

Section: The Blob Modelmentioning

confidence: 86%

“…Consequently, our model is defined by the free energy (19), where F b is that given within the framework of the blob model by (13) with (14). We note that we can use the same analysis as pointed out in reference [24], to show that the boundary condition (20) can naturally emerge from the model recently introduced by Cohen and Muthukumar [37], in the context of the critical wetting of twocomponent polymer blends.…”

Section: The Model and Equation For The Profilementioning

confidence: 92%

“…We assume that the bulk energy to be the classical FloryHuggins energy given by (13), with the effective Flory interaction parameter defined by (14). The surface free energy F s is a functional of the composition x 0 on the surface [33,34].…”

Section: The Model and Equation For The Profilementioning

confidence: 99%

“…Also, the effective Flory interaction parameter χ is inversely proportional to temperature. Expression (14) can be understood, in a certain sense, as a renormalization of interactions due to the chemical difference between species A and B. Expression (14) calls the following remark.…”

Section: The Blob Modelmentioning

confidence: 99%

“…Phase separation in ternary polymer-polymer-solvents mixtures is the subject of a great deal of attention in both theoretical [1][2][3][4][5][6][7][8][9] and experimental [10][11][12][13][14][15][16][17][18][19][20] studies. From a theoretical point of view, the study of the phase separation within these systems has been done using, first, the random phase approximation (RPA) [5], and second, the blob model [8], which is a direct consequence of the renormalization theory.…”

Section: Introductionmentioning

confidence: 99%

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Phase separation of polymer blends in solution near adsorbing surface

2000

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In this paper, we consider a mixture of two polymers A and B of different chemical nature, dissolved in a common good solvent, in contact with an interacting surface. We start from a mixture of two incompatible homopolymers A and B in the molten state, and assume that the surface adsorbs strongly one or both polymer species at high temperature. It is assumed that this is a strong adsorption, so that chains cannot desorb once they are linked to the surface. This constrains the system to a quenched composition on the surface. Once the adsorption process is finished, a quantity of a good solvent is added to get a semi-dilute solution. We assume that demixing transition in the presence of solvent occurs at lower temperature. The purpose is to discuss the influence of the quenched surface fluctuations on the critical properties of the mixture. Within the framework of the so-called blob model, we determine the exact shape of the composition profile as a function of the distance z to the surface, for any value of the relevant parameters, namely, the temperature T , the molecular weight M , the monomer concentration c and the surface composition x 0. Our analysis reveals a universal character of the composition profile for D z ξt, where the characteristic size D is some known length depending on the relevant parameters of the problem, and not on temperature, and ξt is the thermal correlation length. Near surface, for a z D (a is the monomer size), the profile is no longer universal, and in particular, it is sensitive to the boundary condition. Far from the surface, that is z ξt, the profile tends exponentially to its bulk value. We show that the length D approaches its lowest value as the surface composition reaches its saturated value l. In this limit, we find that the profile shape is a characteristic of critical adsorption in simple binary fluid mixtures. Finally, this work must be regarded as a natural extension of a previous one, which was concerned with the same problem, but in the absence of solvent.

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Section: The Blob Modelmentioning

confidence: 86%

Section: The Model and Equation For The Profilementioning

confidence: 92%

Section: The Model and Equation For The Profilementioning

confidence: 99%

Section: The Blob Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phase separation of polymer blends in solution near adsorbing surface

2000

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Specific Refractive Index Increments of Polymers in Dilute Solution

Michielsen

1999

The Wiley Database of Polymer Properties

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Liquid‐liquid phase separation in multicomponent polymer systems, 21. Deuterium isotope effect in polymer compatibility

et al. 1984

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The spinodal and, hence, the miscibility gap of relatively short chain polystyrene/polybutadiene (PS/PB) mixtures is shifted by 14 "C towards higher temperatures, if the hydrogen in PB is replaced by deuterium. The shift corresponds to a difference in the heat of mixing of about 0,2 kJ per mole of styrene units for a 1 : 1 PS/PB mixture. The effect has been observed by means of Gordon's Pulse Induced Critical Scattering method and the resulting spinodals are found to differ also with respect to the location of their maximum which indicates disparity in the entropy of mixing. For the prediction of the spinodal in a polystyrene/polybutadiene/perdeutereous polybutadiene (PS/PBH/PBD6) system the assumption of non-athermal mixing in PBH/PBD6 is needed. The value estimated for the PBH/PBD6 interaction parameter involves the second virial coefficient for solutions of PBD6 in PBH to be very close to zero. Expressions are presented for the second virial coefficient in quasiternary systems by scattering methods.Very recently we became aware of a theoretical treatment by Buckingham and Hentschel of the partial miscibility of liquid mixtures of hydrogenous and deutereous high polymerss3). These authors conclude that the heat of mixing must be expected to be positive, but so small that the chains must have a considerable length before partial miscibility of the upper critical type can occur. Assuming the gz3 value discussed above not to depend on the chain lengths we can calculate for a symmetrical case (mz = m3 = m) that chains longer than rn = 104 would not mix in all proportions. It is of interest to note that the experimental heats of mixing reported by

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Interaction between polymers in dilute solutions of two polymers in a single solvent measured by light scattering and the compatibility of polymers

Cited by 21 publications

References 5 publications

Phase separation of polymer blends in solution near adsorbing surface

Phase separation of polymer blends in solution near adsorbing surface

Specific Refractive Index Increments of Polymers in Dilute Solution

Liquid‐liquid phase separation in multicomponent polymer systems, 21. Deuterium isotope effect in polymer compatibility

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