Association of block copolymers in selective solvents, 1. Measurements on hydrogenated poly(styrene‐isoprene) in decane and in <i>trans</i>‐decalin

Mandema, W.; Zeldenrust, H.; Emeis, C.A.

doi:10.1002/macp.1979.021800611

Cited by 53 publications

(28 citation statements)

References 18 publications

(1 reference statement)

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“…As an alternative extrapolation we have used the Heller + k'c (8) which are readily obtained from the Huggins and Kraemer equations. Equations 7 and 8 are recommended when the Huggins coefficient is higher than 0.5.15 The concentration dependences of / ß and c/ln ( ) for copolymer SEP1 in n-octane at 25 °C are plotted in Figure 10.…”

Section: Methodsmentioning

confidence: 99%

Micellization of a polystyrene-block-poly(ethylene/propylene) copolymer in n-alkanes. 2. Structural study

Quintana¹,

Villacampa²,

Andrio³

et al. 1992

Macromolecules

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The concentration and temperature dependences of micelle formation by a polystyrene-felocftpoly(ethylene/propylene) copolymer in n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and n-hexadecane are examined by light scattering and viscometry. At concentrations above the cmc an unusually large scattering intensity is found. The experimental dependences of light scattering and viscosity data on the concentration were always linear within the concentration range of 1 X 10~3 to 5 X 10"3 g-cm~3 for all the n-alkanes and temperatures studied. Molar mass and dimension of the micelles have been found to be independent of temperature. The variation of weight-average molar mass and hydrodynamic radius with the carbon number of the n-alkane shows a minimum for n-octane at higher temperatures (70 °C), whereas at low temperatures (25 °C) these magnitudes increase as the carbon number of the n-alkane increases. This behavior agrees with the values of the standard Gibbs energy of micellization that we have found for the different n-alkanes. Small and positive values of the second virial coefficient have been found, and they can be explained by taking into account that the formation of micelles leads to less unfavorable contacts between the polystyrene segments and the n-alkane molecules. The apparent radius of gyration of the micelles hardly depends on the n-alkane except for n-heptane. A larger value of the apparent radius of gyration has been found in this solvent. Heller equations have been employed to determine the limiting viscosity number of the micelles, since the Huggins and Kraemer equations do not lead to the same value. The hydrodynamic radius varies with temperature and carbon number of the n-alkane in a very similar way to the weight-average molar mass. We have found that temperature and solvent markedly influence the free chain-micelle equilibrium. However, this influence is relatively small on the molar mass and size of the micelles.

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Section: Methodsmentioning

confidence: 99%

Micellization of a polystyrene-block-poly(ethylene/propylene) copolymer in n-alkanes. 2. Structural study

Quintana¹,

Villacampa²,

Andrio³

et al. 1992

Macromolecules

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“…Systematic work from both experimental and theoretical points of view − has been devoted to the study of micelles formed by diblock copolymers. Similar studies have been extended to triblock copolymers, mainly for solvents selective for the outer blocks. − Relatively few studies on the formation of micelles composed of graft copolymers or more complex structures have appeared in the literature. − Most of this work, with some exceptions, deals with rather ill-defined copolymers, characterized by chemical and compositional heterogeneity, broad molecular weight distributions, and poor control over the number and the placement of the branches along the backbone.…”

Section: Introductionmentioning

confidence: 99%

Micellization of Model Graft Copolymers in Dilute Solution

et al. 1997

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The micellization behaviors of graft copolymers consisting of polystyrene, PSt, backbones and poly(tert-butyl methacrylate), PtBuMA, or poly(methacrylic acid), PMAA, branches were studied in dilute solutions by low angle laser light scattering, LALLS, viscometry, and dynamic light scattering, DLS. tert-Amyl alcohol, a selective solvent for the PtBuMA branches, and tetrahydrofuran, THF, a selective solvent for the PSt backbones, were used to promote the formation of micelles from the PSt-g-PtBuMA and PSt-g-PMAA graft copolymers, respectively. Low aggregation numbers were obtained in all cases due to the specific architectural characteristics of the samples. Aggregation numbers were dependent on the type of the component (backbone or branches) that was insoluble in the selective solvent. The formation of micelles from the PSt-g-PtBuMA graft copolymers in tert-amyl alcohol is evidenced by the appearance of large and rather loose aggregates at a certain concentration range. This kind of behavior was not observed for the micelles formed from the graft copolymers with PMAA branches in THF. Stable and compact structures were obtained in this case, with their hydrodynamic behavior resembling that of hard spheres.

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“…The micelle formation in selective solvents (pure and mixed solvents) for each block has been studied using several techniques viz. light scattering (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), viscosity (4,7,9,(13)(14)(15), osmometry (12,15,16), ultramicroscopy (1 9), electron microscopy (19)(20)(21), gel permeation chromatography (20), nmr (22,23), small angle X-ray scattering (17,18,24,25), photon correlation spectroscopy (19,26), and sedimentation measurements (10,15).…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic studies on micellar solutions of styrene–butadiene block copolymers in selective solvents

Oranli¹,

Bahadur²,

Riess³

1985

Can. J. Chem.

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LEVENT ORANLI, PRATAP BAHADUR, and GERARD RIESS. Can. J. Chem. 63, 2691 (1985). Hydrodynamic radius of micelles of several block copolymers in different selective solvents (for both types of blocks) was determined from photon correlation spectroscopy. The boundaries of micellar solutions in heptane (good solvent for polybutadiene block) and dimethylformamide (good solvent for polystyrene block) were established for polymers in terms of their molecular mass and block composition. The photon correlation spectroscopy data in combination with intrinsic viscosities of block copolymers in selective solvents were used to determine micellar molecular mass and aggregation number. The influence of temperature on the micelle size was examined. The block copolymer micelles could solubilize a certain amount of insoluble homopolymer within their insoluble core. 'H nmr spectra were examined to study the influence of temperature on micellar systems.LEVENT ORANLI, PRATAP BAHADUR et GERARD RIESS. Can. J. Chem. 63, 2691 (1985). Le rayon hydrodynamique des micelles de copolymkres blocs formks dans difftrents solvants stlectifs de l'une ou de l'autre stquence a kt6 dttermink par spectroscopie de photocorrklation. Pour ces copolymkres du type polystyrkne-block-polybutaditne on a dkfini le domaine d'existence des solutions micellaires dans I'heptane (solvant sklectif de la stquence polybutadikne) et dans le dimCthylformamide (solvant sklectif de la sequence polystyrkne) en fonction de la masse moltculaire et de la composition. La masse molkculaire des micelles et le nombre d'agrkgation ont ttt dkterminks sur la base de la viscositk intrinskque des copolymkres et des rksultats de spectroscopie de photocorrklation. On a exarnink par ailleurs I'influence de la temp6rature sur la taille des micelles et la solubilisation d'homopolymkres dans le coeur de celles-ci. Les caracttristiques micellaires du systkme ont kt6 ktudikes par spectroscopie rmn du proton ? I diffkrentes temptratures.

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Association of block copolymers in selective solvents, 1. Measurements on hydrogenated poly(styrene‐isoprene) in decane and in trans‐decalin

Cited by 53 publications

References 18 publications

Micellization of a polystyrene-block-poly(ethylene/propylene) copolymer in n-alkanes. 2. Structural study

Micellization of a polystyrene-block-poly(ethylene/propylene) copolymer in n-alkanes. 2. Structural study

Micellization of Model Graft Copolymers in Dilute Solution

Hydrodynamic studies on micellar solutions of styrene–butadiene block copolymers in selective solvents

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