Three-dimensional observation of confined phase-separated structures in block copolymer nanoparticles

Higuchi, Takeshi; Motoyoshi, Kiwamu; Sugimori, Hidekazu; Jinnai, Hiroshi; Yabu, Hiroshi; Shimomura, Masatsugu

doi:10.1039/c2sm07139h

Cited by 66 publications

(55 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When these dual units interact with one another in large numbers, the interplay between attractive and repulsive forces gives rise to a plethora of self-organized morphologies. [57][58][59][60][61] In numerical studies, while confinement of copolymers has been extensively investigated with the assistance of probabilistic methods 11,28,[62][63][64] and cell dynamics simulation, 34,[65][66][67] still little is known on how confined morphologies are directly related to the parameters of a free energy functional. [1][2][3][4][5] Among the different types of three-dimensional confinements, cylindrical 2,3,6-27 and spherical 11,[28][29][30][31][32][33][34][35][36][37][38][39] confinements have been extensively studied with the aim of developing diverse technological applications such as the design of nanoreactors [40][41][42][43] and sophisticated vehicles possessing a rich internal structure for drug delivery, 44-51 among others.…”

Section: Introductionmentioning

confidence: 99%

Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn–Hilliard equations

et al. 2016

Self Cite

View full text Add to dashboard Cite

We numerically study a set of coupled Cahn-Hilliard equations as a means to find morphologies of diblock copolymers in three-dimensional spherical confinement. This approach allows us to find a variety of energy minimizers including rings, tennis balls, Janus balls and multipods among several others. Phase diagrams of confined morphologies are presented. We modify the size of the interface between microphases to control the number of holes in multipod morphologies. Comparison to experimental observation by transmission electron microtomography of multipods in polystyrene-polyisoprene diblock copolymers is also presented.

show abstract

Section: Introductionmentioning

confidence: 99%

Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn–Hilliard equations

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…100 Deviations from the bulk behavior have been observed especially under strong confinement conditions, i.e., when the droplet diameter approaches the periodicity of the block copolymer. 101 Although this concept was demonstrated for triblock terpolymers 102 and dentritic linear block copolymers, 103 diblock copolymers are by far the most reported, most likely because they are easier accessible and block orientation can be predicted with high certainty. Polymer-rich droplets are produced by drop-wise addition of water immiscible polymer solutions to water, e.g., polystyrene-block-poly(4vinylpyridine) (PS-b-P4VP) in chloroform), under vigorous stirring or sonication (Fig.…”

Section: Self-assembly Of Ab Diblock Copolymersmentioning

confidence: 99%

Self-assembly concepts for multicompartment nanostructures

2015

View full text Add to dashboard Cite

Compartmentalization is ubiquitous to many biological and artificial systems, be it for the separate storage of incompatible matter or to isolate transport processes. Advancements in the synthesis of sequential block copolymers offer a variety of tools to replicate natural design principles with tailor-made soft matter for the precise spatial separation of functionalities on multiple length scales. Here, we review recent trends in the self-assembly of amphiphilic block copolymers to multicompartment nanostructures (MCNs) under (semi-)dilute conditions, with special emphasis on ABC triblock terpolymers. The intrinsic immiscibility of connected blocks induces short-range repulsion into discrete nano-domains stabilized by a third, soluble block or molecular additive. Polymer blocks can be synthesized from an arsenal of functional monomers directing self-assembly through packing frustration or response to various fields. The mobility in solution further allows the manipulation of self-assembly processes into specific directions by clever choice of environmental conditions. This review focuses on practical concepts that direct self-assembly into predictable nanostructures, while narrowing particle dispersity with respect to size, shape and internal morphology. The growing understanding of underlying self-assembly mechanisms expands the number of experimental concepts providing the means to target and manipulate progressively complex superstructures.

show abstract

“…Similar frustrated morphologies from the 2D confinement have been predicted by Monte Carlo simulation. 45 A sphere 46,47 and an inverted sphere (e.g., inverse opals 48 ) have been used for 3D confinement. The frustrated morphologies in spherical confinement have been investigated from both experimental 46,48,49 and theoretical 50−52 viewpoints.…”

Section: Accounts Of Chemical Researchmentioning

confidence: 99%

Three-Dimensional Visualization and Characterization of Polymeric Self-Assemblies by Transmission Electron Microtomography

et al. 2017

Self Cite

View full text Add to dashboard Cite

* S Supporting Information CONSPECTUS: Self-assembling structures and their dynamical processes in polymeric systems have been investigated using three-dimensional transmission electron microscopy (3D-TEM). Block copolymers (BCPs) self-assemble into nanoscale periodic structures called microphase-separated structures, a deep understanding of which is important for creating nanomaterials with superior physical properties, such as high-performance membranes with well-defined pore size and high-density data storage media. Because microphase-separated structures have become increasingly complicated with advances in precision polymerization, characterizing these complex morphologies is becoming increasingly difficult. Thus, microscopes capable of obtaining 3D images are required. In this article, we demonstrate that 3D-TEM is an essential tool for studying BCP nanostructures, especially those self-assembled during dynamical processes and under confined conditions. The first example is a dynamical process called order−order transitions (OOTs). Upon changing temperature or pressure or applying an external field, such as a shear flow or electric field, BCP nanostructures transform from one type of structure to another. The OOTs are examined by freezing the specimens in the middle of the OOT and then observing the boundary structures between the preexisting and newly formed nanostructures in three-dimensions. In an OOT between the bicontinuous double gyroid and hexagonally packed cylindrical structures, two different types of epitaxial phase transition paths are found. Interestingly, the paths depend on the direction of the OOT. The second example is BCP self-assemblies under confinement that have been examined by 3D-TEM. A variety of intriguing and very complicated 3D morphologies can be formed even from the BCPs that self-assemble into simple nanostructures, such as lamellar and cylindrical structures in the bulk (in free space). Although 3D-TEM is becoming more frequently used for detailed morphological investigations, it is generally used to study static nanostructures. Although OOTs are dynamical processes, the actual experiment is done in the static state, through a detailed morphological study of a snapshot taken during the OOT. Developing time-dependent nanoscale 3D imaging has become a hot topic. Here, the two main problems preventing the development of in situ electron tomography for polymer materials are addressed. First, the staining protocol often used to enhance contrast for electrons is replaced by a new contrast enhancement based on chemical differences between polymers. In this case, no staining is necessary. Second, a new 3D reconstruction algorithm allows us to obtain a high-contrast, quantitative 3D image from fewer projections than is required for the conventional algorithm to achieve similar contrast, reducing the number of projections and thus the electron beam dose. Combining these two new developments is expected to open new doors to 3D in situ real-time structural observation of polymer materials.

show abstract

Three-dimensional observation of confined phase-separated structures in block copolymer nanoparticles

Cited by 66 publications

References 67 publications

Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn–Hilliard equations

Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn–Hilliard equations

Self-assembly concepts for multicompartment nanostructures

Three-Dimensional Visualization and Characterization of Polymeric Self-Assemblies by Transmission Electron Microtomography

Contact Info

Product

Resources

About