Materials self-assembly and fabrication in confined spaces

Ramanathan, Mala; Kilbey, S. Michael; Ji, Qingmin; Hill, Jonathan P.; Ariga, Katsuhiko

doi:10.1039/c2jm16629a

Cited by 78 publications

(61 citation statements)

References 350 publications

(358 reference statements)

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“…[56] Use of a patterned substrate to direct assembly has proven promising for reducing the defect density of other self-organizing systems too. [11,62] Here, we survey results for a variety of material chemistries, showing the versatility of this technique and applicability to the field of optics. The templatedirected assembly can be based on topographic patterns, chemical surface modifications, and confinement effects.…”

Section: Wwwadvopticalmatdementioning

confidence: 99%

Template‐Directed Solidification of Eutectic Optical Materials

Kulkarni

Kohanek

Tyler

et al. 2018

Advanced Optical Materials

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polarizers, some waveguides, and many lasers. [1][2][3] Materials with powerful optical functionalities, including negative-index of refraction and optical chirality, can be realized by appropriate placement of materials with suitable properties in 2D or 3D space. [4][5][6] Light in the visible spectrum can be manipulated, although the tolerance for defects is exceedingly low at visible frequencies, and the number of materials with the appropriate properties is limited. [7,8] Most photonic crystals are fabricated by high-resolution top-down 2D patterning methods such as electron-beam lithography, interference lithography, and focused ion beam milling. [9] However, it is challenging to fabricate large-area bulk materials with these techniques, especially with intricate internal structures. [8] Additionally, many materials with promising optical properties are not compatible with these top-down patterning methods. [4,10] As work on colloidal crystals has shown, controlled self-assembly is an effective route to organizing materials into 3D architectures, which interact strongly with light. [9][10][11][12][13] Colloidal self-assembly, however, only offers a limited set of symmetries (generally those of close packed arrangements), and a spherical basis. [12] For many applications, considerably more complex structures are of interest. Particularly promising approaches for forming materials with complex internal microstructures include eutectic solidification and block copolymer self-assembly, [14][15][16][17] and materials with interesting optical properties have been reported using both approaches. These methods are advantageous due to the wide range of microstructures they form. Here, we focus on the structures formed by eutectic solidification since materials with a broader range of optical properties are available compared to that provided by block copolymers, and because the characteristic lengths of structures accessible through eutectic solidification better match the wavelengths of visible and IR light. Further, forming materials with sufficiently large characteristic dimensions for interaction with visible light by block copolymer assembly is synthetically challenging as it requires high molecular weight polymers. [18] Similarly, self-assembly of other building blocks, e.g., nanoparticles, [19,20] molecules, [21,22] and DNA, [23,24] tend to produce structures with characteristic dimensions too small to provide strong light-matter interactions (via diffractive phenomena), [2,3,25] and are thus not the emphasis of this review.Mesostructured materials can exhibit enhanced light-matter interactions, which can become particularly strong when the characteristic dimensions of the structure are similar to or smaller than the wavelength of light. For controlling visible to near-infrared wavelengths, the small characteristic dimensions of the required structures usually demand fabrication by sophisticated lithographic techniques. However, these fabrication methods are restricted to producing 2D and a limited range of 3D...

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Section: Wwwadvopticalmatdementioning

confidence: 99%

Template‐Directed Solidification of Eutectic Optical Materials

Kulkarni

Kohanek

Tyler

et al. 2018

Advanced Optical Materials

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“…The behavior of fluids changes dramatically when they are injected into small pores because of the increasing importance of the boundary conditions and molecule-surface interactions. Various modes of confinement, such as topological, chemical, biological, and interfacial, can affect structural and kinetic aspects of fluid behavior, such as phase equilibria, mechanical and viscoelastic properties, diffusion, fluid flow, and, therefore, the matrix penetrability [2]. Such dramatic modification of the fluid properties under confinement can be efficiently exploited in a variety of technologies, provided there are ways of controlling the surface chemistry and internal structures of the target porous material at the macroscopic (pores with sizes R > 500 Å), mesoscopic (20 R 500 Å), microscopic (R < 20 Å), and molecular levels [3].…”

Section: Porous Media For Energy Environmental and Biomedical Applimentioning

confidence: 99%

Structural Characterization of Porous Materials Using SAS

Melnichenko

2016

Small-Angle Scattering From Confined and Interfacial Fluids

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This chapter begins with an overview of various engineered and naturally occurring porous solids and their applications in modern technologies. Different modes of confinement, such as topological, chemical, biological, and interfacial, can affect structural and kinetic aspects of the fluid phase equilibria, mechanical and viscoelastic properties, diffusion, and flow in confined spaces. Such dramatic modification of the fluid properties under confinement can be efficiently exploited in a variety of technologies, provided there are ways of controlling the internal structures and surface chemistry of the target porous material at the macroscopic, mesoscopic, microscopic, and molecular levels. SAS represents a nonintrusive technique that can provide information on the structure of porous media that is inaccessible to other methods of structural characterization. The rest of the chapter is devoted to the description of SAS structural analysis of porous silicas, carbons, membranes, polymer monoliths, sedimentary rocks and other common materials.

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“…Other authors point to the presence of 'pinning' sites at the substrate surface that result in high defect densities. [20][21][22] To overcome the substrate limitations, a surface pre-treatment with a hydroxyl-terminated polydimethylsiloxane (PDMS-OH) homopolymer brush is usually required. [ 7,13 ] However, it should be noted that the use of a PDMS-OH brush may present further problems for pattern transfer into the substrate.…”

Section: Introductionmentioning

confidence: 99%

Graphoepitaxial Directed Self‐Assembly of Polystyrene‐Block‐Polydimethylsiloxane Block Copolymer on Substrates Functionalized with Hexamethyldisilazane to Fabricate Nanoscale Silicon Patterns

Borah

Rasappa

Senthamaraikannan

et al. 2014

Adv Materials Inter

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In block copolymer (BCP) nanolithography, microphase separated polystyrene‐block‐polydimethylsiloxane (PS‐b‐PDMS) thin films are particularly attractive as they can form small features and the two blocks can be readily differentiated during pattern transfer. However, PS‐b‐PDMS is challenging because the chemical differences in the blocks can result in poor surface‐wetting, poor pattern orientation control and structural instabilities. Usually the interfacial energies at substrate surface are engineered with the use of a hydroxyl‐terminated polydimethylsiloxane (PDMS‐OH) homopolymer brush. Herein, we report a facile, rapid and tuneable molecular functionalization approach using hexamethyldisilazane (HMDS). The work is applied to both planar and topographically patterned substrates and investigation of graphoepitaxial methods for directed self‐assembly and long‐range translational alignment of BCP domains is reported. The hexagonally arranged in‐plane and out‐of‐plane PDMS cylinders structures formed by microphase separation were successfully used as on‐chip etch masks for pattern transfer to the underlying silicon substrate. The molecular approach developed here affords significant advantages when compared to the more usual PDMS‐OH brushes used.

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Materials self-assembly and fabrication in confined spaces

Cited by 78 publications

References 350 publications

Template‐Directed Solidification of Eutectic Optical Materials

Template‐Directed Solidification of Eutectic Optical Materials

Structural Characterization of Porous Materials Using SAS

Graphoepitaxial Directed Self‐Assembly of Polystyrene‐Block‐Polydimethylsiloxane Block Copolymer on Substrates Functionalized with Hexamethyldisilazane to Fabricate Nanoscale Silicon Patterns

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