Phase transition of block copolymer/homopolymer binary blends under 2D confinement

Kim, Youngkeol; Mun, Je Ho; Yu, Guiduk; Char, Kookheon

doi:10.1007/s13233-017-5128-3

Cited by 10 publications

(5 citation statements)

References 34 publications

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“…Block copolymer (BCP) composed of chemically different blocks has attracted researchers over decades because the BCP generates fascinating self-assembled structures in nanoscale dimensions, and researchers have proposed many applications in nanotechnology, microelectronics, and clean energy. − To correlate the physical properties of BCP with specific applications, it is imperative to attain fundamental understanding on the thermodynamic behaviors and phase transitions of BCPs in terms of their molecular parameters, as reported in many theoretical and experimental studies. − In the case of symmetric A–B diblock copolymers, the BCPs undergo an order-to-disorder transition (ODT) from a lamellar structure to a disordered state upon decreasing segregation power of χ N , where χ and N represent the Flory–Huggins interaction parameter between two blocks and the overall degree of polymerization, respectively. , Thus, an ODT-type phase transition of BCPs similarly pertains to the upper critical solution transition (UCST) in the binary polymer blends, as the χ is inversely proportional to temperature ( T ). , …”

Section: Introductionmentioning

confidence: 99%

Composition Fluctuation Inhomogeneity of Symmetric Diblock Copolymers: χN Effects at Order-to-Disorder Transition

Jun

Lee

et al. 2017

Macromolecules

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Section: Introductionmentioning

confidence: 99%

Composition Fluctuation Inhomogeneity of Symmetric Diblock Copolymers: χN Effects at Order-to-Disorder Transition

Jun

Lee

et al. 2017

Macromolecules

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“…We hypothesize that this phenomenon stems from local entropic penalties for each BCP layer within the onion-like PS- b -P4VP particles. In concentric lamellar structures, the BCP chains near the center experience stronger entropic penalties (i.e., stretching penalty) due to their higher local curvature . Thus, Au NPs may selectively segregate at the central domains of each layer to alleviate BCP chain stretching.…”

Section: Resultsmentioning

confidence: 99%

“…In concentric lamellar structures, the BCP chains near the center experience stronger entropic penalties (i.e., stretching penalty) due to their higher local curvature. 60 Thus, Au NPs may selectively segregate at the central domains of each layer to alleviate BCP chain stretching. The change in entropy between the domains of onion-like BCP particles gives the potential to control the number of Au NP layers (N) formed within the ALO particles.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Entropy-Driven Assembly of Nanoparticles within Emulsion-Evaporative Block Copolymer Particles: Crusted, Seeded, and Alternate-Layered Onions

Lee

et al. 2020

Chem. Mater.

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Hybrid organic/inorganic systems with modulated nanostructures and well-defined morphologies are of great importance to develop novel nanomaterials with tailored functionalities. Herein, we report the tunable assemblies of polystyrene-grafted Au nanoparticles (Au@PS NPs) within onion-like particles of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP), controlled by the molecular weight (M n ) of PS ligands. Coassembly of Au@PS and PS-b-P4VP through solvent-evaporative emulsions exhibits dramatic morphological changes in the NP assemblies depending on the M n of PS ligands: (1) addition of low M n (1.8 kg mol −1 ) Au@PS creates crusted onion-like hybrid particles with well-ordered hexagonal NP superlattices covering their surface; (2) in contrast, high M n (6.4 kg mol −1 ) Au@PS segregate at PS domains of the block copolymer particles. Interestingly, these NPs form a hexagonal packing structure at the center of the PS domains, producing concentric lamellar particles with hierarchically stacked Au@PS in an alternate-layered onion-like structure. Finally, cryogenic electron microscopy analysis is conducted to probe the entropy-driven mechanism of the formation of these hybrid particles. These initial demonstrations of multicomponent hybrid particles with targeted spatial alignments offer new strategies to design complex nanomaterials with tailorable properties for potential technological applications.

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“…An interesting parameter that can be employed to influence BCP self-assembly is homopolymer additives. While homopolymer additives have been widely investigated for their ability to tune the self-assembly of BCP in the bulk [12][13][14] phase, studies that examine the effects of these homopolymer on corresponding systems in solution are comparatively limited [15]. A better understanding of homopolymer effects can allow more scientists to take advantage of this potentially facile approach to manipulate BCP morphology in solution for various applications.…”

Section: Introductionmentioning

confidence: 99%

Controlling the morphology of poly(ethylene glycol)-b-poly(lactide) (PEG-PLA) self-assemblies in solution: Interplay of homopolymer additive and kinetic traps

Lim,

Parikh,

Venkatraman

et al. 2023

Preprint

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Block copolymer (BCP) self-assembly involves various components in the system interacting in diverse and intricate ways to result in a final state. This paper explores the how homopolymer additives and kinetic traps can be used to control the morphology of self-assembly of poly(ethylene glycol)-b-poly(lactide) (PEG-PLA) nanostructures in water. By kinetically trapping PEG-PLA nanostructures formed in the presence of a non-adsorbing PEG homopolymer, we reveal how different concentrations and molecular weights of the added PEG was found to be able to induce micelle-to-vesicle transitions. This phenomenon was ascribed to a change in the molecular geometry of the underlying BCP induced by the added PEG homopolymer due largely to excluded volume screening effects. In addition, we demonstrated the reverse vesicle-to-micelle transition upon homopolymer removal, and the kinetic nature of the system rendered the transition effect time and temperature dependent. Analysis of the intermediate transition structures reinforces our proposed mechanism involving the change in the underlying molecular geometry of the PEG-PLA BCP. As proof of concept, we showed how our understanding of the PEG-PLA system allowed us successfully utilize the PEG-PLA vesicles thermoresposive delivery systems. We showed how the vesicles was able to retain dye at low temperature (4℃) and the release can be triggered upon heating (37℃). Overall, the work here introduces a novel means of regulating the morphology and behavior of BCP nanostructures, which can have important downstream applications.

show abstract

Phase transition of block copolymer/homopolymer binary blends under 2D confinement

Cited by 10 publications

References 34 publications

Composition Fluctuation Inhomogeneity of Symmetric Diblock Copolymers: χN Effects at Order-to-Disorder Transition

Composition Fluctuation Inhomogeneity of Symmetric Diblock Copolymers: χN Effects at Order-to-Disorder Transition

Entropy-Driven Assembly of Nanoparticles within Emulsion-Evaporative Block Copolymer Particles: Crusted, Seeded, and Alternate-Layered Onions

Controlling the morphology of poly(ethylene glycol)-b-poly(lactide) (PEG-PLA) self-assemblies in solution: Interplay of homopolymer additive and kinetic traps

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