Dynamics of ternary polymer blends: Disordered, ordered and bicontinuous microemulsion phases

Morkved, Terry L.; Chapman, Bryan; Bates, Frank S.; Lodge, Timothy P.; Štěpánek, Petr; Almdal, Kristoffer

doi:10.1039/a809169b

Cited by 54 publications

(80 citation statements)

References 38 publications

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“…16 An equivalent one-phase gap was observed between the micro-and macrophase separated states in the more low-molar mass system of PEE-PDMS, PEE and PDMS being poly͑ethyl ethylene͒ and poly͑dim-ethyl siloxane͒, respectively. [17][18][19] Moreover, in the near vicinity of the mean field Lifshitz point, this system showed critical exponents that are significantly larger relative to both mean field and 3d-Ising behavior. 17 In another SANS study on the PE-PP, PE, and PP mixture, PE and PP being poly͑ethyl ethylene͒ and head-to-head poly͑propylene͒, respectively, a qualitatively similar phase behavior was found; in particular, the microemulsion phase could be identified by the use of contrast variation technique.…”

Section: Introductionmentioning

confidence: 99%

Thermal composition fluctuations near the isotropic Lifshitz critical point in a ternary mixture of a homopolymer blend and diblock copolymer

Schwahn

Mortensen

Frielinghaus

et al. 2000

The Journal of Chemical Physics

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We have studied thermal composition fluctuations of a ternary symmetric homopolymer/diblock copolymer system of PEE/PDMS/PEE-PDMS ͓PEE and PDMS being poly͑ethyl ethylene͒ and poly͑dimethyl siloxane͒, respectively͔ in its disordered state with small angle neutron scattering for concentration ⌽ of diblocks up to 15%. The phase diagram shows three characteristic regimes; ͑1͒ below the Lifshitz concentration ⌽ LL Х9%; ͑2͒ in the very near vicinity of the Lifshitz concentration; and ͑3͒ above ⌽ LL . In the regime ͑1͒ of low diblock content the maximum neutron intensity is obtained at Qϭ0 and phase separation into macroscopic large domains is observed at low temperatures. With increasing diblock content the thermal fluctuations indicate a crossover from 3d-Ising to isotropic Lifshitz critical behavior with critical exponents of the susceptibility ␥ ϭ(1.62Ϯ0.01) and correlation length ϭ(0.99Ϯ0.04) appreciably larger than in the 3d-Ising case. In the structure factor this crossover is accompanied by a strong reduction of the Q 2 term leading to the dominance of the Q 4 term; the restoring force of the thermal fluctuations is strongly reduced as the Q 2 term is proportional to the surface energy. Near the Lifshitz critical temperature a further crossover was observed leading to the appreciably larger critical exponents ␥ϭ(2.44Ϯ0.08) and ϭ(1.22Ϯ0.08) and a stabilization of the disordered regime visible through a decrease of the phase boundary by nearly 10 K. This crossover is interpreted by the formation of fluctuation induced inhomogeneous diblock distribution at the interface of the thermal fluctuations. ͑2͒ In the intermediate regime between 9% and 12% diblock content the Lifshitz line was crossed twice upon increasing the temperature from low to high temperatures; at low and high temperatures the structure factor S(Q) shows diblock character ͑maximum of S(Q) at Q 0͒ while at intermediate temperature blendlike character ͑maximum of S(Q) at Qϭ0͒. At low temperatures a transition to a bicontinuous microemulsion phase is proposed. ͑3͒ At diblock content of 15% a weak order-disorder transition was observed. The data in the Lifshitz critical range and larger than the Lifshitz line could be interpreted by a recently developed theory of Kielhorn and Muthukumar who considered the effect of thermal fluctuations in ternary homopolymer/diblock copolymer samples and from which the Flory-Huggins parameter could be evaluated.

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Section: Introductionmentioning

confidence: 99%

Thermal composition fluctuations near the isotropic Lifshitz critical point in a ternary mixture of a homopolymer blend and diblock copolymer

Schwahn

Mortensen

Frielinghaus

et al. 2000

The Journal of Chemical Physics

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“…The system under investigation was the ternary model system consisting of symmetric AB copolymers as well as A and B homopolymers, the homopolymers being α = 0.2 times as long as the copolymers. This system had previously been the object of a series of experiments conducted by Bates et al [31,32,33]. Mean-field calculations of its phase diagram predict a Lifshitz critical point where the disordered, lamellar, and phase-separated regions meet [34,35].…”

Section: Introductionmentioning

confidence: 99%

Formation and structure of the microemulsion phase in two-dimensional ternary AB+A+B polymeric emulsions

Düchs

Schmid

2004

The Journal of Chemical Physics

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We present an analysis of the structure of the fluctuation-induced microemulsion phase in a ternary blend of balanced AB diblock copolymers with equal amounts of A and B homopolymers. To this end, graphical analysis methods are employed to characterize two-dimensional configuration snapshots obtained with the recently introduced Field-Theoretic Monte Carlo (FTMC) method. We find that a microemulsion forms when the mean curvature diameter of the lamellar phase coincides roughly with the periodicity of the lamellar phase. Further, we provide evidence to the effect of a subclassification of the microemulsion into a genuine and a defect-driven region.

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“…), can be incorporated more easily in density functional approaches [103,104]. Density functionals have also served as a starting point for the development of dynamical theories which allow to study the evolution of multiphase polymer blends in time [105][106][107][108] Figure: Reprinted from [454]. Copright (1999) with permission from Royal Society of Chemistry.…”

Section: Related Mean Field Approachesmentioning

confidence: 99%

Theory and Simulation of Multiphase Polymer Systems

Schmid

2011

Handbook of Multiphase Polymer Systems

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The theory of multiphase polymer systems has a venerable tradition. The 'classical' theory of polymer demixing, the Flory-Huggins theory, was developed in the 1940s [1,2]. It is still the starting point for most current approaches -be they improved theories for polymer (im)miscibility that take into account the microscopic structure of blends more accurately, or sophisticated field theories that allow to study inhomogeneous multicomponent systems of polymers with arbitrary architectures in arbitrary geometries. In contrast, simulations of multiphase polymer systems are quite young. They are still limited by the fact that one must simulate a large number of large molecules in order to obtain meaningful results. Both powerful computers and smart modeling and simulation approaches are necessary to overcome this problem.In the limited space of this chapter, we can only give a taste of the state-of-the-art in both areas, theory and simulation. Since the theory has reached a fairly mature stage by now, many aspects of it are covered in textbooks on polymer physics [3][4][5][6][7][8][9]. The information on the state-of-the art of simulations is much more scattered. This is why we have put some effort into putting together a representative list of references in this area -which is of course still far from complete.The chapter is organized as follows. In Section II, we briefly introduce some basic concepts of polymer theory. The purpose of this part is to make the chapter accessible to readers who are not very familiar with polymer physics; it can safely be skipped by the others. Section III is devoted to the theory of multiphase polymer systems. We recapitulate the Flory-Huggins theory and introduce in particular the concept of the Flory interaction parameter (the χ parameter), which is a central ingredient in most theoretical descriptions of multicomponent polymer systems. Then we focus on one of the most successful mean-field theories for inhomogeneous (co)polymer blends, the self-consistent field theory. We sketch the main idea, discuss various Handbook of Multiphase Polymer Systems, First Edition. Edited by Abderrahim Boudenne, Laurent Ibos, Yves Candau, and Sabu Thomas.

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Dynamics of ternary polymer blends: Disordered, ordered and bicontinuous microemulsion phases

Cited by 54 publications

References 38 publications

Thermal composition fluctuations near the isotropic Lifshitz critical point in a ternary mixture of a homopolymer blend and diblock copolymer

Thermal composition fluctuations near the isotropic Lifshitz critical point in a ternary mixture of a homopolymer blend and diblock copolymer

Formation and structure of the microemulsion phase in two-dimensional ternary AB+A+B polymeric emulsions

Theory and Simulation of Multiphase Polymer Systems

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