Regulation and control of polymer network deformation in reverse-mode polymer-stabilised cholesteric texture

Chu, Yutian; Yin, Zhiping; Sha, Junqing; Xu, Chao; Zhang, Guobing; Lv, Guoqiang; Qiu, Longzhen; Lu, Hongbo

doi:10.1080/02678292.2016.1230895

Cited by 8 publications

(4 citation statements)

References 23 publications

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“…It is estimated that an energy savings of 20% can be made through smart windows due to the reduced power for cooling and heating, but we also notice that the operation of smart windows still consumes unwanted electrical power, which increases as the window size scales up. − In this case, a self-powered smart window or a window driven by green power is highly demanded to achieve genuine energy savings and environmental protection. Over the past several years, many efforts have been devoted to develop self-powered smart windows, where components with special functionality are incorporated.…”

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confidence: 99%

Normally Transparent Tribo-Induced Smart Window

Wang

Meng

et al. 2020

ACS Nano

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Self-powered smart windows are desirable with the expectations of their energy-saving, weather-independent, usercontrollable, and miniature performance. Recently developed solaror thermal-powered smart windows largely depend on the weather conditions and have an extremely slow response, and only a certain portion of the saved energy can be utilized by the external circuit for mode conversion. In this work, a self-powered normally transparent smart window was developed by the conjunction of a rotary freestanding sliding triboelectric nanogenerator (RFS-TENG) and a polymer network liquid crystal (PNLC) cell. To fabricate the PNLC cell, the alignment layer with randomly distributed microdomains was constructed to encapsulate a mixture of LC polymers and nematic LCs. The opacity of the smart window exposed to an alternating electric field was considerably improved owing to the embedded microdomains and a dense web of LC polymers. The ultrahigh haziness greatly alleviates the charge density required for the LC actuation and thus enables the driving by the TENG where the charge amount is usually limited. The RFS-TENG was elaborately designed with six periodic bent triboelectric films and Ag electrodes, which presented an ultralow friction wear and met the frequency requirement to achieve the steady opacity. By harvesting the mechanical energies from ambient environments, the tribo-induced smart window can benefit a wide variety of fields, such as self-powered sunroofs, wind-driven smart farming systems etc.

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confidence: 99%

Normally Transparent Tribo-Induced Smart Window

Wang

Meng

et al. 2020

ACS Nano

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“…To fabricate the tunable IR reflector, a cholesteric liquid crystal mixture similar to a previous report was used [28,39]. The LC mixture consisted of both reactive (polymerizable) and non-reactive (non-polymerizable) mesogens mixed with a photoinitiator (Irgacure 369).…”

Section: Resultsmentioning

confidence: 99%

“…This was explained by a transition from a non-uniform pitch distortion into a uniform pitch gradient when the cell gap increases [28]. There are also studies demonstrated that the polymer network deformation and helical twisting power of chiral dopants could influence the electrically induced dynamic response of the PSCLC based cells [39,40].…”

Section: Introductionmentioning

confidence: 99%

Cell thickness dependence of electrically tunable infrared reflectors based on polymer stabilized cholesteric liquid crystals

Haan

Khandelwal

et al. 2017

Sci. China Mater.

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We reported here the fabrication of the electrically tunable infrared (IR) reflectors based on the polymer stabilized cholesteric liquid crystal (PSCLC) with negative dielectric anisotropy. A systematic study of the influence of cell gap on the electrically tunable reflection bandwidth was performed. When a direct current (DC) electric field was applied, the reflection bandwidth red shifted in the cells with small cell gap, whereas the bandwidth broadening was observed in the cells with large cell gap. It is therefore reasonable to deduct that the reflection is dictated by the pitch gradient steepness which strongly relies on the cell thickness. The results reveal that for making PSCLC based IR reflector windows with electrically induced bandwidth broadening, a minimal cell gap thickness is required. The resulted IR reflectors possess a short native switching time and long-term operation stability, and are potentially applicable as smart energy saving windows in buildings and automobiles.

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“…[20] However, the high polymer content of PDLCs that operate smart windows requires a high operating voltage, an obstacle restricting their usage in daily life. [19,[21][22][23][24][25] Simultaneously, a PSLC is used in this system, where the LC materials serve as the continuous matrix, and a tiny portion of the polymer network (usually a few percent by weight) is dissolved in the anisotropic fluid. Compared with PDLC films, PSLC-based smart windows show a highly transparent condition and a low driving voltage because of the low polymer content.…”

Section: Introductionmentioning

confidence: 99%

Self‐Assembled Multistable Scattering Mode for Versatile Energy‐Saving Smart Windows

Selvaraj,

Cheng,

Kuo

et al. 2023

Laser & Photonics Reviews

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Smart windows are crucial to dynamic control over light transmission to fulfill various demands in energy saving, privacy, and information display; however, most present technologies still perform a single function (often tint or haze adjustment) and require continuous electricity for operation. In this study, novel self‐assembled ionic liquid crystals (ILCs) doped with negative cholesteric liquid crystals (CLCs) to offer electrically switchable and stable scattering‐mode light modulators are presented. The novel smectic A phase based on the ILCs exhibits high solubility in the adopted nematics, enhancing the LC device's performance in several ways, including improved homogeneity, stable alignment quality, prolonged stability, and simplified fabrication. The LC device can potentially offer a dynamically rapid switching function between stable transparent (imperfect fingerprint textures) states and stable scattering (focal conic textures with small domains) states by using external stimuli and highly maintained multistable states for prolonged periods, even when the external stimuli are removed. The LC device also offers polarization‐independent scattering and transparent‐mode LC light modulators, low operating voltage, excellent contrast, and broad viewing angles. Its versatility and outstanding field‐off stability make it ideal for various applications such as smart lighting, building climate control, energy‐saving displays, and augmented reality (AR) glasses.

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Regulation and control of polymer network deformation in reverse-mode polymer-stabilised cholesteric texture

Cited by 8 publications

References 23 publications

Normally Transparent Tribo-Induced Smart Window

Normally Transparent Tribo-Induced Smart Window

Cell thickness dependence of electrically tunable infrared reflectors based on polymer stabilized cholesteric liquid crystals

Self‐Assembled Multistable Scattering Mode for Versatile Energy‐Saving Smart Windows

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