Simple and Accurate Calibration of the Flory–Huggins Interaction Parameter

Willis, J. D.; Beardsley, Tom; Matsen, Mark W.

doi:10.1021/acs.macromol.0c02115

Cited by 32 publications

(28 citation statements)

References 63 publications

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“…Moreover, none of the SCFT predictions for this system ,, correctly predict the phase sequence with temperature. There is, however, reason for optimism going forward in this vein because of a recent breakthrough in the methods for estimating χ parameters from experimental data …”

Section: Key Outstanding Questionsmentioning

confidence: 99%

Frank–Kasper Phases in Block Polymers

Dorfman

2021

Macromolecules

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The discovery of the Frank−Kasper σ phase in diblock copolymer and tetrablock terpolymer melts catalyzed a renewed interest over the past decade in understanding particle-forming phases in block polymer systems. This Perspective provides a concise overview of the Frank−Kasper phases seen to date in block polymers (A15, σ, and the C14 and C15 Laves phases) and mechanisms known to produce them: conformational asymmetry in neat diblock copolymer melts, interfacial segregation effects in diblock copolymer blends, particle swelling in diblock copolymer/homopolymer blends, and matrix segregation effects in neat tetrablock terpolymer melts. While a qualitative understanding of the emergence of Frank−Kasper phases in block polymer systems has been achieved, a number of outstanding questions remain, in particular those arising from the low degree of polymerization used in experiments, nonequilibrium effects during thermal processing, and the large design space available in blends and multiblock systems. This Perspective discusses potential avenues for future research related to these areas as well as overarching issues underlying the connections between Frank−Kasper phase formation in block polymers to other soft matter and metals.

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Section: Key Outstanding Questionsmentioning

confidence: 99%

Frank–Kasper Phases in Block Polymers

Dorfman

2021

Macromolecules

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“…The earliest treatment by Fredrickson and Helfand [ 24 ] predicted a shift of

, where

is the invariant polymerization index. Particle-based simulations of different models [ 8 , 9 , 10 , 11 ] have since provided the more accurate prediction

…”

Section: Applicationsmentioning

confidence: 99%

“…Consequently, they can all be mapped onto the standard Gaussian chain model (GCM) [ 5 ], which is a minimal model that treats block copolymer systems as incompressible melts of thin elastic threads that interact by pairwise contact forces. At present, the most accurate method of performing the mapping is the Morse calibration [ 4 , 6 ], which has been well demonstrated for experiments [ 7 ] and particle-based simulations [ 8 , 9 , 10 , 11 , 12 ], as well as field-theoretic simulations [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Field-Theoretic Simulations for Block Copolymer Melts Using the Partial Saddle-Point Approximation

Matsen

Beardsley

2021

Polymers

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Field-theoretic simulations (FTS) provide an efficient technique for investigating fluctuation effects in block copolymer melts with numerous advantages over traditional particle-based simulations. For systems involving two components (i.e., A and B), the field-based Hamiltonian, Hf[W−,W+], depends on a composition field, W−(r), that controls the segregation of the unlike components and a pressure field, W+(r), that enforces incompressibility. This review introduces researchers to a promising variant of FTS, in which W−(r) fluctuates while W+(r) tracks its mean-field value. The method is described in detail for melts of AB diblock copolymer, covering its theoretical foundation through to its numerical implementation. We then illustrate its application for neat AB diblock copolymer melts, as well as ternary blends of AB diblock copolymer with its A- and B-type parent homopolymers. The review concludes by discussing the future outlook. To help researchers adopt the method, open-source code is provided that can be run on either central processing units (CPUs) or graphics processing units (GPUs).

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“…When two different types of polymer chains are mixed together, the relative interaction between monomers, characterized by the χ parameter, is a dominant factor that determines the miscibility of the blends. − Although the relative interaction is critical to the thermodynamics of polymer blends, the flexibility of a single polymer chain, determined solely by intramolecular interactions such as torsional and bending potential energies, is often considered as an intrinsic property of the individual chain. − Whether the relative flexibility of a chain of interest (compared to the flexibility of other chains) may affect the spatial arrangement, the conformation, and even the transport of the chain has remained elusive. In this work, we report coarse-grained molecular dynamics (MD) simulations for a single ring chain in thin polymer films of linear chains.…”

Section: Introductionmentioning

confidence: 99%

Relative Chain Flexibility Determines the Spatial Arrangement and the Diffusion of a Single Ring Chain in Linear Chain Films

2021

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The flexibility of a single polymer chain, characterized by its persistence length, is considered to be an intrinsic property of the polymer chain, which determines its conformation and transport properties. In this work, we find from molecular dynamics simulations for a single ring polymer chain in thin films of linear chain melts that the relative flexibility of the ring chain (compared to the flexibility of linear chains) determines where the ring polymer chain is located within thin films and how fast the ring polymer chain diffuses laterally. In this work, we tune the flexibility of ring and linear chains by changing the bending angle potential parameter, while other intra- and intermolecular interaction potentials are identical for both ring and linear chains. We find that it is not the flexibility of individual polymer chains but the relative flexibility that determines the spatial arrangement of the ring chain in thin polymer films. When a ring polymer chain is more flexible (more rigid) than linear polymer chains, the ring polymer is more likely to be located at the film surface (the film center). Such spatial arrangement should originate from the conformational entropy of the ring polymer chain. The ring chain at the film surface is compressed more than that at the film center. This makes the ring chain at the surface threaded less by linear chains. Because the relatively flexible ring chain prefers the film surface (which is more mobile than at the film center) and experiences less entanglement, the relatively flexible ring chain diffuses faster than the relatively rigid ring chain.

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Simple and Accurate Calibration of the Flory–Huggins Interaction Parameter

Cited by 32 publications

References 63 publications

Frank–Kasper Phases in Block Polymers

Frank–Kasper Phases in Block Polymers

Field-Theoretic Simulations for Block Copolymer Melts Using the Partial Saddle-Point Approximation

Relative Chain Flexibility Determines the Spatial Arrangement and the Diffusion of a Single Ring Chain in Linear Chain Films

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