Chemically directed self-assembly of perpendicularly aligned cylinders by a liquid crystalline block copolymer

Yamashita, Nanae; Watanabe, Satoru; Nagai, Keiji; Komura, Motonori; Iyoda, Tomokazu; Aida, Kouhei; Tada, Yutaka; Yoshida, Hiroshi

doi:10.1039/c4tc02851a

Cited by 10 publications

(11 citation statements)

References 50 publications

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“…In general, surface wettability [2][3][4][5] and excluded free volume of the rod like molecules [6][7][8][9] affect the specific orientation of the azobenzene side chain. For example, polymer films with hydrophobic groups containing rod-like side chains such as pentyl-phenyl benzoate, 2 and butyl, 10 pentyl, 11 and hexyl 12 substituted azobenzene all adopted a perpendicular orientation to the substrate. Furthermore, Li and coworkers 13 have previously estimated a tilt angle between small azobenzene molecules (that were self-assembled on the substrate) and the normal surface using reflectance absorption polarized infrared spectroscopy.…”

Section: Orientation Of P5az6a In Supported Thin Filmsmentioning

confidence: 99%

Marangoni Instability Driven Surface Relief Grating in an Azobenzene-Containing Polymer Film

Kim

Wistrom

et al. 2016

Macromolecules

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The Marangoni effect describes fluid flow near an interface in response to a surface tension gradient. Here, we demonstrate that the Marangoni effect is the underlying mechanism for flow driven feature formation in an azobenzene-containing polymer film; features formed in azobenzene-containing polymers are often referred to as surface relief gratings or SRGs. An amorphous poly(4-(acryloyloxyhexyloxy)-4′pentylazobenzene) was synthesized and studied as a model polymer.To isolate the surface tension driven flow from the surface tension pattern inscription step, the surface tension gradient was preprogrammed via photoisomerization of azobenzene in a glassy polymer film without forming topographical features. Subsequently, the latent image was developed in the absence of light by annealing above the glass transition temperature where the polymer is a liquid. The polymer flow direction was controlled with precision by inducing different surface tension changes in the exposed regions, in accordance with expectation based on the Marangoni effect. Finally, the height of the formed features decreased upon extensive thermal annealing due to capillary leveling with two distinct rates. A scaling analysis revealed that those rates originated from dissimilar capillary velocities associated with different azobenzene isomers.

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Section: Orientation Of P5az6a In Supported Thin Filmsmentioning

confidence: 99%

Marangoni Instability Driven Surface Relief Grating in an Azobenzene-Containing Polymer Film

Kim

Wistrom

et al. 2016

Macromolecules

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“…The template provides a <100 nm sized structure as a periodic and thin membrane. [142][143][144][145][146][147] The concept of the biotemplating process directly borrows from natural microstructures for new material fabrications. A use of three-dimensional helical feature in nature is an example of the biotemplate in which helical microalgae, Spirulina (Arthrospira platensis), a naturally shaping lefthanded (LH) open helical structure, was utilized.…”

Section: G Template Processes To Control Micro and Nanostructuresmentioning

confidence: 99%

A review of low density porous materials used in laser plasma experiments

2018

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This review describes and categorizes the synthesis and properties of low density porous materials, which are commonly referred to as foams and are utilized for laser plasma experiments. By focusing a high-power laser on a small target composed of these materials, high energy and density states can be produced. In the past decade or so, various new target fabrication techniques have been developed by many laboratories that use high energy lasers and consequently, many publications and reviews followed these developments. However, the emphasis so far has been on targets that did not utilize low density porous materials. This review therefore, attempts to redress this balance and endeavors to review low density materials used in laser plasma experiments in recent years. The emphasis of this review will be on aspects of low density materials that are of relevance to high energy laser plasma experiments. Aspects of low density materials such as densities, elemental compositions, macroscopic structures, nanostructures, and characterization of these materials will be covered. Also, there will be a brief mention of how these aspects affect the results in laser plasma experiments and the constrictions that these requirements put on the fabrication of low density materials relevant to this field. This review is written from the chemists' point of view to aid physicists and the new comers to this field.

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“…Orientation is also important for periodic nanostructures used as lithographic masks where the nanoscale pores allow for higher feature density than possible with conventional lithography 1,22 . Additionally, gold structures with a uniaxial aligned gyroid morphology have been demonstrated to function as metamaterials for visible light, featuring exotic optical properties that depend on nanostructure orientation 23,24 .…”

Section: Introductionmentioning

confidence: 99%

Aligned platinum nanowire networks from surface-oriented lipid cubic phase templates

et al. 2016

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Chemically directed self-assembly of perpendicularly aligned cylinders by a liquid crystalline block copolymer

Cited by 10 publications

References 50 publications

Marangoni Instability Driven Surface Relief Grating in an Azobenzene-Containing Polymer Film

Marangoni Instability Driven Surface Relief Grating in an Azobenzene-Containing Polymer Film

A review of low density porous materials used in laser plasma experiments

Aligned platinum nanowire networks from surface-oriented lipid cubic phase templates

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