Enhanced electro-optic characteristics of polymer-dispersed nano-sized liquid crystal droplets utilizing PEDOT:PSS polymer composite

Manda, Ramesh; Shin, Hye‐Rim; Lee, Junhyeok; Lim, Young Jin; Kim, Min Su; Lee, Seung Hee

doi:10.1016/j.molliq.2020.114959

Cited by 23 publications

(3 citation statements)

References 28 publications

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“…The normal-mode meant that the film was opaque at the off-state and clear at the on-state, while the reverse-mode meant that the film was clear at the off-state and opaque at the on-state. The normal-mode film was typically based on the polymer-dispersed liquid crystal (PDLC), which was named after the composite structure of dispersing liquid crystal microdroplets uniformly in a homogeneous polymer matrix during polymerization. − The reverse-mode film was mainly made from the polymer-stabilized liquid crystal (PSLC), which was named after the application mechanism of the anchoring stabilization effect of oriented liquid crystalline polymers on the alignment of liquid crystals, formed by in situ photopolymerization of liquid crystalline curable monomers in a preoriented liquid crystal cell. , The reverse-mode film matched the vast majority of application scenarios as transparency was the main state and met the requirements of energy conservation; meanwhile, the film was free of side-view haze problem which was caused by refractive index mismatch at the clear state, and furthermore no safety issues were caused by sudden power outages in comparison to PDLC, which broadened the application prospect. − However, there were still challenging issues of weak mechanical strength inhibiting its large-scale flexible production . There was a weak connection between the polymer and substrates demanding van de Waals force alignment effect here, and the polymer content was extremely low constrained by sharply increasing anchoring force to the liquid crystal, thereby deteriorating E–O properties. ,, …”

Section: Introductionmentioning

confidence: 99%

Reverse-Mode Polymer-Stabilized Liquid Crystal Films with Enhanced Peel Strength and Electro-Optical Performance Based on Photoreactive Self-Assembly Alignment Layers and Patterned Polymer Walls

Wu,

Zou,

Shi

et al. 2024

ACS Appl. Mater. Interfaces

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Polymer-stabilized liquid crystal (PSLC) is a promising material toward the practical application of serving as energy-saving reverse-mode smart windows owing to its superior electro-optical (E–O) properties, simple and efficient processability, and compatibility to most practical circumstances. However, its feeble peel strength originated from low polymer content and poor adhesion between polymer networks and substrates inhibited its large-scale flexible film production. It is still a challenging task to derive good mechanical properties and superior E–O performance for PSLCs at the same time. In this study, a highly durable liquid crystal/polymer composite film showing enhanced peel strength and excellent E–O properties was attained by simultaneously building photoreactive self-assemble alignment layers through an efficient one-step method and the sculpture of a patterned polymer wall structure. This film has comprehensive ascendant E–O properties of lower driving voltages, faster response times, and higher contrast ratio, together with an over 30 times lift of the peel strength. The effectuation mechanisms of the alignment, E–O properties, peel-strength, microstructures, and cyclic durability of the films have been systematically studied. This novel liquid crystal/polymer composite film demonstrates advantages in every aspect of performance compared to traditional PSLC devices, which hoards promising applications in smart windows for cars and buildings.

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Section: Introductionmentioning

confidence: 99%

Reverse-Mode Polymer-Stabilized Liquid Crystal Films with Enhanced Peel Strength and Electro-Optical Performance Based on Photoreactive Self-Assembly Alignment Layers and Patterned Polymer Walls

Wu,

Zou,

Shi

et al. 2024

ACS Appl. Mater. Interfaces

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“…The use of smart windows can save up to 70% of the energy used for heating and cooling in buildings [2]. Different smart window systems has been proposed such as suspended particle devices [3], micro-blinds [4], polymer-dispersed liquid crystals [5], electrochromic [6], thermochromic devices [7], and photochromic materials [8]. Photochromic materials change their optical transmittance in response to light irradiation.…”

Section: Introductionmentioning

confidence: 99%

Photochromic TiO2/PEGDA organogels

Eglı̅tis

Šutka

2022

Photochem Photobiol Sci

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Photochromic materials can be used for modulation of the visible and infrared light transmittance for providing privacy or energy saving by blocking the heat. Titanium dioxide (TiO 2 ) nanoparticles has been well reported as a promising photochromic material. However, a high photochromic response from TiO 2 can be observed only when the nanoparticles are dispersed in a strong photogenerated hole scavenger at a liquid state, but polymer composites are less responsive due to lack of hole scavenging capability. However, it is intricate to apply suspensions in real window devices because of possible leaking. Here, we describe the preparation of TiO 2 quantum dot (QD)-based gels from polyethylene glycol diacrylate (PEGDA), N,N-Dimethylformamide (DMF), and ethanol (EtOH). Photochromic gels with TiO 2 contents (1-5 volume%) show performance comparable to their colloidal counterparts with capable of photodarkening within 30 min with a transmittance change ranging from 35.8 to 84.5% at 550 nm. These gels were capable of fully recovering the initial transmittance when not exposed to ultraviolet (UV) light within 3-8 h. The photochromic gel systems with ethanol shows reasonable stability by decreasing in transmittance recovery only by less than 10% in 10 cycles. A potential application for the developed photochromic gels can be photochromic windows.

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“…Thus, PLC materials can combine both the stimuli-responsive properties of LCs and the excellent mechanical properties of polymers. [8][9][10][11][12] The most typical application of PLC materials is in the field of smart windows, [13][14][15][16] which can dynamically adjust the optical transmittance. These electrochromic materials also have potential applications in display, sensing, and other fields.…”

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confidence: 99%

MWCNT Doped Reverse-Mode Polymer Network Liquid Crystals with Frequency Response Property

Li 李,

Ji 姬,

Zhang 张

et al. 2024

Chinese Phys. Lett.

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Polymer-liquid crystals (PLC) is a common material for smart windows. However, PLC smart windows usually require high driving voltage to maintain transparency. In this work, we synthesized a novel PLC smart film by doping multi-wall carbon nanotubes (MWCNT) into a reverse-mode polymer network liquid crystal (R-PNLC). It was found that doping MWCNT could effectively reduce the threshold voltage (V th) of R-PNLC from 19.0V to 8.4V. Due to co-orientation between MWCNT and LC molecules, the doped R-PNLC was able to maintain a high transmittance of visible light (~80%) without an applied electric field. We found that doping MWCNT could change the frequency modulation property of R-PNLC. The doped R-PNLC exhibits a wider frequency modulation range up to 40,000Hz, while the frequency modulation of the undoped R-PNLC reached to a saturation at 23,000 Hz. We also tested the electromagnetic interference (EMI) shielding efficiency of R-PNLC and found that the EMI shielding efficiency could be improved by doping only 0.01wt% MWCNT into the system. The total shielding effectiveness (SET) value of 0.01wt% MWCNT doped R-PNLC was up to 14.91 dB during frequency band of 5.38 GHz-8.17 GHz. This study demonstrates that the films are potentially useful for low-energy-consumption smart windows with enhanced electromagnetic shielding capability.

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Enhanced electro-optic characteristics of polymer-dispersed nano-sized liquid crystal droplets utilizing PEDOT:PSS polymer composite

Cited by 23 publications

References 28 publications

Reverse-Mode Polymer-Stabilized Liquid Crystal Films with Enhanced Peel Strength and Electro-Optical Performance Based on Photoreactive Self-Assembly Alignment Layers and Patterned Polymer Walls

Reverse-Mode Polymer-Stabilized Liquid Crystal Films with Enhanced Peel Strength and Electro-Optical Performance Based on Photoreactive Self-Assembly Alignment Layers and Patterned Polymer Walls

Photochromic TiO2/PEGDA organogels

MWCNT Doped Reverse-Mode Polymer Network Liquid Crystals with Frequency Response Property

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