Normal- and Reverse-Mode Thermoresponsive Controllability in Optical Attenuation of Polymer Network Liquid Crystals

Kakiuchida, Hiroshi; Matsuyama, Akihiko; Ogiwara, Akifumi

doi:10.1021/acsami.9b01280

Cited by 17 publications

(8 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermally responsive P-LC materials were prepared based on the liquid crystal phase transition. Hiroshi Kakiuchida 144 et al developed a nonuniform irradiation method for photopolymerization-induced phase separation. The transparent and scattering states of LC/polymer films were controlled by temperature-induced phase separation of nuclei, and thermally responsive polymer network liquid crystal films in normal mode and reverse mode were developed, as shown in Fig.…”

Section: Principles Of Lc-based Light Protectionmentioning

confidence: 99%

See 1 more Smart Citation

Advanced liquid crystal-based switchable optical devices for light protection applications: principles and strategies

Zhang

Han

et al. 2023

Light Sci Appl

View full text Add to dashboard Cite

With the development of optical technologies, transparent materials that provide protection from light have received considerable attention from scholars. As important channels for external light, windows play a vital role in the regulation of light in buildings, vehicles, and aircrafts. There is a need for windows with switchable optical properties to prevent or attenuate damage or interference to the human eye and light-sensitive instruments by inappropriate optical radiation. In this context, liquid crystals (LCs), owing to their rich responsiveness and unique optical properties, have been considered among the best candidates for advanced light protection materials. In this review, we provide an overview of advances in research on LC-based methods for protection against light. First, we introduce the characteristics of different light sources and their protection requirements. Second, we introduce several classes of light modulation principles based on liquid crystal materials and demonstrate the feasibility of using them for light protection. In addition, we discuss current light protection strategies based on liquid crystal materials for different applications. Finally, we discuss the problems and shortcomings of current strategies. We propose several suggestions for the development of liquid crystal materials in the field of light protection.

show abstract

Section: Principles Of Lc-based Light Protectionmentioning

confidence: 99%

“…As early as the late 1960s, researchers found that when low-frequency electric fields were applied to some Reproduced with permission from ref. 144 . Copyright 2019, American Chemical Society nematic liquid crystals, the LCs exhibited significant hydrodynamic instabilities.…”

Section: Dynamic Scatteringmentioning

confidence: 99%

Advanced liquid crystal-based switchable optical devices for light protection applications: principles and strategies

Zhang

Han

et al. 2023

Light Sci Appl

View full text Add to dashboard Cite

show abstract

“…Ogiwara et al . developed structures consisting of meso‐scale domains organized with multiaxially orientation‐ordered liquid crystals and orientation‐disordered reactive mesogens for normal‐ and reverse‐mode thermoresponsive light control [131,132] …”

Section: Thermochromic Smart Windowsmentioning

confidence: 99%

“…[129,130] Ogiwara et al developed structures consisting of meso-scale domains organized with multiaxially orientation-ordered liquid crystals and orientation-disordered reactive mesogens for normal-and reverse-mode thermoresponsive light control. [131,132] Several other efforts have been made for thermochromic windows. For example, VO 2 coatings have been fabricated using 3D-printed technology on glass surfaces to selectively block sunlight during summer and allow it during winter.…”

Section: Thermochromic Smart Windowsmentioning

confidence: 99%

Multi‐stimuli‐responsive and Multi‐functional Smart Windows

et al. 2022

View full text Add to dashboard Cite

Smart windows can change their optical characteristics according to environmental conditions or external stimuli (such as heat and electricity). They are manufactured by considering building characteristics, regional climate, energy policies, and indoor air conditions. Their key optical properties have been improved by developing novel materials, fabrication methods, and designs. The optical properties can be further improved by developing multi‐stimuli‐responsive smart window systems. Recently, some smart windows have been integrated with energy storage, solar energy harvesting, self‐cleaning, and air‐purifying functions. The energy consumed by buildings and houses accounts for a considerable portion of the total energy consumed by a country as well as the world; therefore, these state‐of‐the‐art smart windows will greatly contribute to saving energy. Moreover, some multi‐functional smart windows can help in addressing environmental challenges. This mini‐review particularly focuses on discussing the recent advances made in multi‐stimuli‐responsive and multi‐functional smart windows, in addition to summarizing the researches on electrochromic, thermochromic, and other types of smart windows.

show abstract

“…However, they are inferior in the controllability of scattering intensity to electrically operated PNLCs since the molecular orientation of LCs is less ordered in the absence of electric fields. The nonuniform irradiation technique was a successful external method for producing meso-scale nonuniform structures of (i) and (ii) and enabled various thermoresponsive changes in light scattering. , In the present study, we address this issue via internal material design and use monofunctional reactive mesogens (RMs) possessing cyanobiphenyl (CB) groups as found in the mesogenic body of the LCs, as shown in Scheme . The RMs become normal chain polymers accompanying CB branches by polymerization reactions of acryloyl groups via PPIPS.…”

Section: Introductionmentioning

confidence: 99%

Thermoresponsive Reflective Scattering of Meso-Scale Phase Separation Structures of Uniaxially Orientation-Ordered Liquid Crystals and Reactive Mesogens

Kakiuchida

Kabata²,

Matsuyama³

et al. 2021

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Polymer network liquid crystals (PNLCs) capable of thermoresponsive change in reflective scattering were fabricated using a self-organization technique called photopolymerization-induced phase separation. These PNLCs exhibit nonscattering states at temperatures τ below the nematic-to-isotropic (NI) phase transition temperature τNI but reflective scattering states at τ values above τNI. The magnitude of change of optical clarity is 80% and of solar transmittance is 20% in PNLCs with a thickness of 50 μm. The microscopic structures consist of wavelength- or meso-scale phase separation domains of liquid crystals (LCs) and polymerized reactive mesogens (RMs) in which cyanobiphenyl (CB) groups are thermoresponsively transformed between uniaxially orientation-co-ordered and disordered states. Such thermoresponsive structures were fabricated by employing the CB groups as mesogenic bodies, which were expected to mutually associate due to their physicochemical structures. Cross-linkers stabilized the meso-scale domains and made the PNLCs durable through repeated temperature changes. Polarizing optical microscopy (POM) and scanning electron microscopy showed meso-scale composites that reflectively scatter visible and near-infrared light. POM and Fourier-transform infrared spectroscopy at different temperatures suggest that the orientation order of the CB groups changes in the LC phase in response to temperature but remains ordered in the RM phase. Such a thermoresponsive change in the orientation order produces the switchability in meso-scale nonuniformity and consequently in reflective light scattering. The thermoresponsive PNLCs are not only effective as energy-saving smart windows but also advantageous at stages of manufacture, installation, and operation.

show abstract

Normal- and Reverse-Mode Thermoresponsive Controllability in Optical Attenuation of Polymer Network Liquid Crystals

Cited by 17 publications

References 27 publications

Advanced liquid crystal-based switchable optical devices for light protection applications: principles and strategies

Advanced liquid crystal-based switchable optical devices for light protection applications: principles and strategies

Multi‐stimuli‐responsive and Multi‐functional Smart Windows

Thermoresponsive Reflective Scattering of Meso-Scale Phase Separation Structures of Uniaxially Orientation-Ordered Liquid Crystals and Reactive Mesogens

Contact Info

Product

Resources

About