Takahiro Seki

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT"Command surfaces" of Langmuir-Blodgett films. Photoregulations of liquid crystal alignment by molecularly tailored surface azobenzene layersTakahiro Seki, Masako Sakuragi, Yuji Kawanishi, Takashi Tamaki, Ryoichi Fukuda, Kunihiro Ichimura, and Yasuzo SuzukiCite this: Langmuir 1993, 9, 1, 211–218Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 January 1993https://doi.org/10.1021/la00025a041RIGHTS

Alignment methods of nematic liquid crystals (LCs) by surface photoreactions on substrate surfaces were initially proposed around 1990, and the photoalignment technology of nematic LCs has recently been integrated into the LC device fabrication industry due to its profitable features. Accumulated efforts in this field have revealed that applications of photoalignment processes are not limited to conventional nematic LCs but that a variety of functional materials can also be manipulated according

The photoalignment of liquid crystalline materials has been studied extensively over the past two and a half decades and has recently become of technological importance in the liquid crystal display panel industry. This review introduces recent attempts at the photoalignment of liquid crystalline polymers and focuses on two aspects. First, strategies to ensure effective in-plane alignment of photoresponsive mesogens are highlighted. Despite the numerous investigations reported to date, film syst

Slide-ring topological gels with mobile cross-linking units are a new class of soft materials that exhibit distinct features differing from those of conventional chemically or physically cross-linked gels. Photoresponsive behavior arising from the dynamic nature of the cross-linkers is demonstrated for a slide-ring gel prepared by adding azobenzene units to the mobile α-cyclodextrin units of a poly(ethylene oxide)-based polyrotaxane (see figure).

Abstract Molecular and macromolecular assemblies have good “chemistry” with light. In the research of photochromic molecules and systems, the number of papers in the most recent 10 years exceeds the half of the whole past century. Photochromic molecules have been studied for their characteristic color changes. Although the importance in this line has not dimmed, other powerful areas have emerged in the last two or three decades. Much more attention has been drawn to light induced motions trigger

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal isomerization behaviors of a spiropyran in bilayers immobilized with a linear polymer and a smectitic clayTakahiro Seki and Kunihiro IchimuraCite this: Macromolecules 1990, 23, 1, 31–35Publication Date (Print):January 1, 1990Publication History Published online1 May 2002Published inissue 1 January 1990https://pubs.acs.org/doi/10.1021/ma00203a007https://doi.org/10.1021/ma00203a007research-articleACS PublicationsRequest reuse permissionsArticle V

The immense potential of light responsive polymer materials toward technological applications in photonics, mechanics and micro-fabrication has been attracting increasing attention from both materials chemists and physicists.

Photoresponsive azobenzene-containing systems ranging from molecular to macroscopic material levels have greatly been increasing their significance in materials chemistry. This review focuses on the studies on light induced or triggered motions in azobenzene liquid crystalline (LC) polymer films at mesoscopic and microscopic levels. Due to the cooperative nature of liquid crystalline materials, highly efficient photoalignment and photo-triggered migrating motions are realized in mostly repeated

Photoinduced expansion and contraction response in monolayers consisting of a poly(vinyl alcohol) derivative having an azobenzene (Az) side chain at the air−water interface was investigated in detail by surface potential measurements, Brewster angle microscopy (BAM), UV−visible absorption spectroscopy, and the macroscopic area estimations with a Langmuir film balance. Surface potential measurements confirmed the model of photostimulated motions previously supposed (Seki et al., Bull. Chem. Soc.

Abstract Light can be used as a precise stimulus by selecting suitable wavelengths, polarization directions, and intensity, allowing non-contact control. When photoresponsive (mostly photochromic) molecular units are combined with polymeric materials and liquid-crystalline materials, various types of smart photofunctions can be created. Smart functions involve photomechanical responses, photoalignment of anisotropic materials, orientational amplifications, photoinduced phase changes, photo-tunin

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical alignment regulation of a nematic liquid crystal by Langmuir-Blodgett layers of azobenzene polymers as "command surfaces"Takahiro Seki, Takashi Tamaki, Yasuzo Suzuki, Yuji Kawanishi, Kunihiro Ichimura, and Koso AokiCite this: Macromolecules 1989, 22, 8, 3505–3506Publication Date (Print):August 1, 1989Publication History Published online1 May 2002Published inissue 1 August 1989https://pubs.acs.org/doi/10.1021/ma00198a056https://doi.org/10.

This letter describes a compact and high-gain multilayer parasitic microstrip array antenna (MPMAA). The design and performance of the proposed array antenna are presented. The antenna employs three layers with a 2/spl times/2 parasitic array on each layer. The developed prototype MPMAA employs a multilayer low-temperature co-fired ceramic (LTCC) substrate that is well suited to the assembly of MMIC chips. The fabricated MPMAA achieves a 7.17 dBi absolute gain at 60 GHz including the loss derive

This paper proposes a highly efficient multilayer parasitic microstrip antenna array that is constructed on a multilayer Teflon substrate for millimeter-wave system-on-package modules. The proposed antenna achieves a radiation efficiency of greater than 91% and an associated antenna gain of 11.1 dBi at 60 GHz. The antenna size is only 10 mm /spl times/ 10 mm. Additionally, this paper describes a 60-GHz-band prototype antenna employing a multilayer Teflon substrate that is well suited to achievin