Structure control of lattice-patterned liquid crystals–polymer composites prepared by polarization-selective UV-curing through the addition of a fluorinated acrylate monomer

Sung, Shi‐Joon; Jung, Eunhye; Sim, Kyoseung; Kim, Dae-Hwan; Cho, Kuk Young

doi:10.1016/j.mee.2012.09.010

Cited by 8 publications

(3 citation statements)

References 23 publications

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“…Polymer walls (PWs) [6][7][8] have come forward to keep uniform cell gaps of flexible LCDs and have been extensively studied. However, the formation of PWs is usually together with residual monomers in the active areas, and the small line width PWs (about 20μm) are rarely accomplished in the former work.…”

Section: Introductionmentioning

confidence: 99%

16.3: Flexible Liquid Crystal Displays with Fine‐Width Polymer Walls and Self‐Assembled Monolayer Alignment

Gong

Luo

Qiu

et al. 2021

Symp Digest of Tech Papers

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Flexible liquid crystal displays (LCDs) are regarded as one of the most promising candidates to achieve flexible displays. In this paper, we proposed a novel technique to fabricate flexible LCDs combining polymer walls (PWs) and self‐assembled‐monolayer(SAM). The PWs with fine morphology and line‐width (about 20 µm) were fabricated to keep uniform cell gap and provided a larger aperture opening ratio for flexible LCDs. Alignment by alkyl trichlorosilane(TS) SAM was achieved at room temperature. In this way, general flexible substrates could be used for flexible LCDs. This work is promising for the manufacture of flexible LCDs.

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Section: Introductionmentioning

confidence: 99%

16.3: Flexible Liquid Crystal Displays with Fine‐Width Polymer Walls and Self‐Assembled Monolayer Alignment

Gong

Luo

Qiu

et al. 2021

Symp Digest of Tech Papers

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“…Differences in the monomer reactivity, size and cross-linking ability, result in gradients in the monomer chemical potentials [ 27 , 28 , 29 ]. These chemical potentials provide the driving force for monomer migration and for polymer formation in the illuminated regions [ 18 , 22 , 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Forming Spacers in Situ by Photolithography to Mechanically Stabilize Electrofluidic-Based Switchable Optical Elements

et al. 2016

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Electro-Fluidic Displays (EFD) have been demonstrated to be an attractive technology for incorporation into portable display devices. EFDs have excellent optical efficiency and fast switching enabling video content. Ensuring mechanical stability of EFD display cells is a key challenge and essential for developing large area as well as flexible displays. Although the electro-optic performance of an EFD, unlike a liquid crystal display (LCD), is insensitive to cell-gap, extreme changes in cell-gap can result in irreversible collapse of the cell. Here we use photolithography to develop spacers to prevent cell-gap collapse and provide the required mechanical stability for EFD devices. The spacer is formed directly on the cover plates (ITO/glass) after cell assembly with UV light induced phase separation polymerization in the illuminated area. Phase separation behavior between polar aqueous solution and polymer is closely related to the solubility of acrylate monomers. In this work, polyethylene glycol diacrylate (PEGDA) as cross-linker, 2-hydroxyethyl acrylate (HEA) and acrylic acid or acrylamide as co-monomers are investigated for fabricating the spacers. PEGDA was added to the mixtures in order to increase the mechanical strength of the spacer. The spacers showed excellent performance for cell-gap control in EFD devices.

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“…[12,13] For instance, Kim et al [14] proposed a robust vertically aligned LC cell, where the LC were locked by polymer walls, and the azimuthal anchoring on the surface of the alignment layer was controlled by the polymerisation of a UV curable reactive mesogen monomer. As a result, the defect points were trapped at a single position, resulting in a greatly improved response time.…”

Section: Introductionmentioning

confidence: 99%

Reverse-mode polymer dispersed liquid crystal films prepared by patterned polymer walls

et al. 2015

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This article proposes a methodology to prepare polymer dispersed liquid crystal (PDLC) films working in the reverse-mode operation, where the ion-doped nematic liquid crystals (NLCs) with negative dielectric anisotropy (Δε) were locked by polymer walls. On-state and off-state of films were controlled by an electric field. In the absence of an electric field, it appears to be transparent. In the field, the homogeneous alignment NLCs form dynamic scattering, giving rise to opaque. The effect of the cylindrical holes with different diameters of photo masks and liquid crystal Δε on the electro-optical properties and transmittance wavelength range of 400-3000 nm light of samples were investigated. It was found that it exhibited very good electro-optical characteristics, high contrast ratio and excellent infrared energy-efficient of films used as switchable windows.Keywords: reverse-mode polymer dispersed liquid crystal; polymer walls; nematic liquid crystal; negative dielectric anisotropy; electro-optical properties IntroductionPolymer dispersed liquid crystal (PDLC) films are technologically important class of materials that find numerous applications as electrically switchable optical devices.[1-3] PDLC films are formed by liquid crystal (LC) microdroplets embedded in a polymer matrix. They can exhibit either a droplet morphology in which droplets of LC are embedded in a polymer matrix, or a polymer ball morphology in which the LC takes up the voids and the crevices of a network structure formed by small polymer balls. In the normal-mode operation, they are in an opaque state (offstate) and can be turned into a transparent state (onstate) by controlling the LC molecule orientation by means of a suitable voltage. The reverse-mode PDLC films are transparent in its off-state and can be turned into an opaque on-state. A greater interest has been aroused by reverse-mode PDLC films that are useful as switchable windows, automotive applications [4,5] and used in a wide range of applications that need a transparent state in the absence of any applied voltage.Several authors have reported examples of reverse-mode PDLC films obtained by modification of the polymer surface energy,[6] by functionalising the LC/polymer matrix interface,[7] by using dualfrequency addressable LC,[8] by means of rough surfaces [9,10] or by increasing the LC content. [11]

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Structure control of lattice-patterned liquid crystals–polymer composites prepared by polarization-selective UV-curing through the addition of a fluorinated acrylate monomer

Cited by 8 publications

References 23 publications

16.3: Flexible Liquid Crystal Displays with Fine‐Width Polymer Walls and Self‐Assembled Monolayer Alignment

16.3: Flexible Liquid Crystal Displays with Fine‐Width Polymer Walls and Self‐Assembled Monolayer Alignment

Forming Spacers in Situ by Photolithography to Mechanically Stabilize Electrofluidic-Based Switchable Optical Elements

Reverse-mode polymer dispersed liquid crystal films prepared by patterned polymer walls

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