scholarly journals High-Efficiency Responsive Smart Windows Fabricated by Carbon Nanotubes Modified by Liquid Crystalline Polymers

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 440
Author(s):  
Yuan Deng ◽  
Shi-Qin Li ◽  
Qian Yang ◽  
Zhi-Wang Luo ◽  
He-Lou Xie
Keyword(s):  
Carbon Nanotubes ◽  
Liquid Crystalline ◽  
Near Infrared ◽  
High Efficiency ◽  
Polymer Brush ◽  
Light Transmittance ◽  
Smart Window ◽  
Vertical Orientation ◽  
Smart Windows ◽  
Conversion Materials

Smart windows can dynamically and adaptively adjust the light transmittance in non-energy or low-energy ways to maintain a comfortable ambient temperature, which are conducive to efficient use of energy. This work proposes a liquid crystal (LC) smart window with highly efficient near-infrared (NIR) response using carbon nanotubes grafted by biphenyl LC polymer brush (CNT-PDB) as the orientation layer. The resultant CNT-PDB polymer brush can provide the vertical orientation of LC molecules to maintain the initial transparency. At the same time, the smart window shows a rapid response to NIR light, which can quickly adjust the light transmittance to prevent sunlight from entering the room. Different from common doping systems, this method avoids the problem of poor compatibility between the LC host and photothermal conversion materials, which is beneficial for improving the durability of the device.

scholarly journals Preparation and Properties of Thermoresponsive P(N-Isopropylacrylamide-co-butylacrylate) Hydrogel Materials for Smart Windows

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Jae-Hyung Park ◽  
Ji-Won Jang ◽  
Jae-Hak Sim ◽  
Il-Jin Kim ◽  
Dong-Jin Lee ◽  
...  
Keyword(s):  
Light Transmission ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Light Transmittance ◽  
Solar Light ◽  
Solution Temperature ◽  
Smart Window ◽  
Thermoresponsive Polymers ◽  
Smart Windows ◽  
Hydrogel Films

Thermoresponsive polymers that exhibit phase transition in response to temperature change can be used as material for smart windows because they can control solar light transmission depending on the outside temperature. The development of thermoresponsive polymers for a smart window that can be used over a wide temperature range is required. Therefore, to obtain smart window materials that can be used at various temperatures, three-dimensional thermoresponsive P(NIPAm-co-BA) hydrogels were prepared by free radical polymerization from main monomer N-isopropylacrylamide, comonomer butyl acrylate, and crosslinking agent N,N′-methylenebisacrylamide (MBAm) in this study. This study examined the effect of BA content on the lower critical solution temperature (LCST) and the solar light transmittance of crosslinked P(NIPAm-co-BA) hydrogel films. The LCST of hydrogel films was found to be significantly decreased from 34.3 to 29.5°C with increasing BA content from 0 to 20 mol%. It was found that the transparent films at T=25°C (T<LCST) were converted to translucent films at a higher temperature (T=45°C) (T>LCST). These results suggested that the crosslinked P(NIPAm-co-BA) hydrogel materials prepared in this study could have high potential for application in smart window materials.

scholarly journals Optical properties of doping electrochromic M0.125W0.875O3 (M=Mo, Nb, Ta, Ti, V): A first-principles study

2020 ◽  
Author(s):  
Yuanyuan Cui ◽  
Qinfan Wang ◽  
Bin Liu ◽  
Yanfeng Gao
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Near Infrared ◽  
High Efficiency ◽  
Infrared Region ◽  
Smart Window ◽  
Colored State ◽  
Light Region ◽  
Electrochromic Material ◽  
Ti Doping

Abstract Tungsten trioxide (WO3) is a representative electrochromic material that can change their optical properties under the action of a voltage pulse and has attracted great interest in the applications of energy efficient windows. Models of various W0.125M0.875O3 and LixM0.125W0.875O3 (M=Mo, Nb, Ta, Ti, V) were built to simulate the bleached and colored state of WO3 materials by first-principles calculations, respectively. The calculations show that doping systems of LixM0.125W0.875O3 (M= Nb, Ta, V) lead to an enhancement of the modulation efficiency in invisible light and a decrease in the modulation efficiency in near infrared region (NIR). Ti doping boosts an excellent high efficiency of NIR modulation, while no modulation was observed in the visible light region. Mo doping remarkably promotes the coloration efficiency in both NIR and visible regions. The specific characteristics of doped WO3 systems deserve more exploration of their application in green house or thermal modulation smart window.

Near infrared-sensitive smart windows from Au nanorod–polymer hybrid photonic hydrogels

2021 ◽  
Author(s):  
Xin Xiao ◽  
Dongjian Shi ◽  
Zhaokun Yang ◽  
Qiuyan Yu ◽  
Daisaku Kaneko ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Near Infrared ◽  
Smart Window ◽  
Smart Windows ◽  
Polymer Hybrid

We developed a hybrid photonic hydrogel consisting of Au NRs, the P(NIPAm-co-AAm) hydrogel, and a photonic crystal and fabricated a NIR-sensitive smart window.

scholarly journals Multifunctional Smart Window Based on Dielectric Elastomer Actuator

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 32
Author(s):  
Milan Shrestha ◽  
Gih-Keong Lau ◽  
Anand Asundi ◽  
Zhenbo Lu
Keyword(s):  
Flat Glass ◽  
Green Building ◽  
Dielectric Elastomer ◽  
Light Transmittance ◽  
Smart Window ◽  
Smart Windows ◽  
Dielectric Elastomer Actuators ◽  
State Construction ◽  
Soft Actuators ◽  
External Stimuli

Soft actuators are compliant material-based devices capable of producing large deformations upon external stimuli. Dielectric elastomer actuators (DEAs) are a type of soft actuators that operate on voltage stimuli. Apart from soft robotics, these actuators can serve many novel applications, such as tunable optical gratings, lens, diffusers, smart windows and so on. This article presents our current work on tunable smart windows which can regulate light transmittance and sound absorption. This smart window can promote daylighting while maintaining privacy by electrically switching between being transparent and opaque. As a tunable optical surface scatters, it turns transparent with smooth surfaces like a flat glass; however, it turns opaque (translucent) with the micro-rough surface. The surface roughness is varied, employing surface microwrinkling or unfolding by using dielectric elastomer actuation. In addition, this smart window is equipped with another layer of transparent microperforated dielectric elastomer actuators (DEAs), which act like Helmholtz resonators, serving as a tunable and broader sound absorber. It can electrically tune its absorption spectrum to match the noise frequency for maximum acoustic absorption. The membrane tension and perforation size are tuned using DEA activation to tune its acoustic resonant frequency. Such a novel smart window can be made as cheap as glass due to its simple, all-solid-state construction. In the future, they might be used in smart green building and could potentially enhance urban livability.

scholarly journals Dielectric Elastomer Actuator-Based Multifunctional Smart Window for Transparency Tuning and Noise Absorption

Actuators ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 16
Author(s):  
Milan Shrestha ◽  
Gih-Keong Lau ◽  
Anand Asundi ◽  
Zhenbo Lu
Keyword(s):  
Flat Glass ◽  
Dielectric Elastomer ◽  
Light Transmittance ◽  
Smart Window ◽  
Smart Windows ◽  
Dielectric Elastomer Actuator ◽  
State Construction ◽  
Soft Actuators ◽  
Novel Applications ◽  
External Stimuli

Soft actuators are compliant material-based devices capable of producing large deformation upon external stimuli. Dielectric elastomer actuators (DEA) are a type of soft actuator that operates on voltage stimuli. Apart from soft robotics, these actuators can serve many novel applications, for example, tunable optical gratings, lenses, diffusers, smart windows and so on. This article presents our current work on tunable smart windows which can regulate the light transmittance and the sound absorption. This smart window can promote daylighting while maintaining privacy by electrically switching between transparent and opaque. As a tunable optical surface scatters, it turns transparent with smooth surfaces like a flat glass; but it turns ‘opaque’ (translucent) with the micro-rough surface. The surface roughness is varied employing surface micro-wrinkling or unfolding using dielectric elastomer actuation. Moreover, this smart window is equipped with another layer of transparent micro-perforated dielectric elastomer actuator (DEA), which acts like Helmholtz resonators serving as a tunable and broader sound absorber. It can electrically tune its absorption spectrum to match the noise frequency for maximum acoustic absorption. The membrane tension and perforation size are tuned using DEA activation to tune its acoustic resonant frequency. Such a novel smart window can be made as cheap as glass due to its simple all-solid-state construction. In future, they might be used in smart green buildings and could potentially enhance urban livability.

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