Effective interaction parameter of linear/star polymer blends and comparison with that of linear/linear and star/star blends

Theodorakis, Panagiotis E.; Avgeropoulos, Apostolos; Freire, Juan J.; Kosmas, Marios K.; Vlahos, Costas

doi:10.1063/1.2731786

Cited by 7 publications

(6 citation statements)

References 14 publications

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“…Equation ( 7) means that a pair of monomers (A, B) is defined to have a pairwise contact if their distance is less than r n . Similar quantities have been also used to characterize the incompatibility between linear and star chains in polymer melts and blends [76][77][78]. As can be seen from figure 4, the number of contacts A-B averaged over all conformations increases as the number of blocks n increases.…”

Section: Resultsmentioning

confidence: 99%

Analysis of the static properties of cluster formations in symmetric linear multiblock copolymers

Fytas¹,

Theodorakis²

2011

J. Phys.: Condens. Matter

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Abstract. We use molecular dynamics simulations to study the static properties of a single linear multiblock copolymer chain under poor solvent conditions varying the block length N , the number of blocks n, and the solvent quality by variation of the temperature T . We study the most symmetrical case, where the number of blocks of monomers of type A, n A , equals that of monomers B, n B (n A = n B = n/2), the length of all blocks is the same irrespective of their type, and potential parameters are also chosen symmetrically, as for a standard Lennard-Jones fluid. Under poor solvent conditions the chains collapse and blocks with monomers of the same type form clusters, which are phase separated from the clusters with monomers of the other type. We study the dependence of the size of the formed clusters on n, N and T . Furthermore, we discuss our results with respect to recent simulation data on the phase behaviour of such macromolecules, providing a complete picture for the cluster formations in single multiblock copolymer chains under poor solvent conditions.

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Section: Resultsmentioning

confidence: 99%

Analysis of the static properties of cluster formations in symmetric linear multiblock copolymers

Fytas¹,

Theodorakis²

2011

J. Phys.: Condens. Matter

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“…This interfacial tension difference can be attributed to the sterically hindered interaction of PMMA chains with the inner layer of the grafted PS brush, analogous to star-linear polymer blends. 34,35 When comparing the interactions between PMMA and end-grafted PS chains versus linear PS chains, different from star-linear polymer blends, it seems more appropriate to consider a single grafted PS chain instead of all the grafted chains on one particle together. As mentioned earlier, the composition-dependent phase separation behavior of AuPS nanoparticles is more analogous to the linear PS counterpart with the same molecular weight as one grafted chain.…”

Section: Resultsmentioning

confidence: 99%

Pattern-Directed Phase Separation of Polymer-Grafted Nanoparticles in a Homopolymer Matrix

et al. 2016

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The controlled organization of nanoparticle (NP) constituents into superstructures of well-defined shape, composition and connectivity represents a continuing challenge in the development of novel hybrid materials for many technological applications. We show that the phase separation of polymer-tethered nanoparticles immersed in a chemically different polymer matrix provides an effective and scalable method for fabricating defined submicron-sized amorphous NP domains in melt polymer thin films. We investigate this phenomenon with a view towards understanding and controlling the phase separation process through directed nanoparticle assembly. In particular, we consider isothermally annealed thin films of polystyrene-grafted gold nanoparticles (AuPS) dispersed in a poly(methyl methacrylate) (PMMA) matrix. Classic binary polymer blend phase separation related morphology transitions, from discrete AuPS domains to bicontinuous to inverse domain structure with increasing nanoparticle composition is observed, yet the kinetics of the AuPS/PMMA polymer blends system exhibit unique features compared to the parent PS/PMMA homopolymer blend. We further illustrate how to pattern-align the phase-separated AuPS nanoparticle domain shape, size and location through the imposition of a simple and novel external symmetry-breaking perturbation via soft-lithography. Specifically, submicron-sized topographically patterned elastomer confinement is introduced to direct the nanoparticles into kinetically controlled long-range ordered domains, having a dense yet well-dispersed distribution of non-crystallizing nanoparticles. The simplicity, versatility and roll-to-roll adaptability of this novel method for controlled nanoparticle assembly should make it useful in creating desirable patterned nanoparticle domains for a variety of functional materials and applications.

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“…These results are consistent with previous theoretical and experimental researches, which investigated the miscibility of star/linear binary blends based on thermodynamic interaction parameter χ eff . Theodorakis et al compared the effective interactions of linear/star, linear/linear, and star/star polymer blends by Monte Carlo simulations. They found that linear/star blends are more miscible than the corresponding linear/linear blends, and linear/star mixtures are less miscible than star/star blends.…”

Section: Resultsmentioning

confidence: 99%

Positron annihilation lifetime spectroscopy for miscibility investigations of styrene–butadiene–styrene copolymer/polystyrene blends

Meng

Liu

et al. 2013

Polymer Engineering & Sci

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The free volume parameters of styrene-butadiene-styrene copolymer/polystyrene (SBS/PS) blends were investigated with positron annihilation lifetime spectroscopy (PALS) in this study. The behaviors of free volume distribution, average free volume, and relative fractional free volume revealed the difference of interfacial miscibility. Based on different models, inter-chain interaction parameter b, geometric factor g, and hydrodynamic interaction parameter a obtained from free volume data were employed to further determine the effect of molecular architecture and styrene content on the miscibility. The results suggest the better miscibility in star-shaped SBS/PS blends than that of corresponding linear SBS/PS systems, even than that of systems containing more styrene unit. In addition, differential scanning calorimetry, dynamic mechanical analysis, and scanning electron microscopy, which are sensitive to heterogeneities in larger domain size, give different results of miscibility from free volume data. It should be attributed the difference of characterization scale. The mechanical property corroborates the results of miscibility. POLYM. ENG. SCI., 54:785-793, 2014.

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Effective interaction parameter of linear/star polymer blends and comparison with that of linear/linear and star/star blends

Cited by 7 publications

References 14 publications

Analysis of the static properties of cluster formations in symmetric linear multiblock copolymers

Analysis of the static properties of cluster formations in symmetric linear multiblock copolymers

Pattern-Directed Phase Separation of Polymer-Grafted Nanoparticles in a Homopolymer Matrix

Positron annihilation lifetime spectroscopy for miscibility investigations of styrene–butadiene–styrene copolymer/polystyrene blends

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