Engineering Self‐Adaptive Multi‐Response Thermochromic Hydrogel for Energy‐Saving Smart Windows and Wearable Temperature‐Sensing

Abstract

Buildings account for ≈40% of the total energy consumption. In addition, it is challenging to control the indoor temperature in extreme weather. Therefore, energy‐saving smart windows with light regulation have gained increasing attention. However, most emerging base materials for smart windows have disadvantages, including low transparency at low temperatures, ultra‐high phase transition temperature, and scarce applications. Herein, a self‐adaptive multi‐response thermochromic hydrogel (PHC‐Gel) with dual temperature and pH response is engineered through “one‐pot” integration tactics. The PHC‐Gel exhibits excellent mechanical, adhesion, and electrical conductivity properties. Notably, the low critical solubility temperature (LCST) of PHC‐Gel can be regulated over a wide temperature range (20–35 °C). The outdoor practical testing reveals that PHC‐Gel has excellent light transmittance at low temperatures and radiation cooling performances at high temperatures, indicating that PHC‐Gel can be used for developing energy‐saving windows. Actually, PHC‐Gel‐based thermochromic windows show remarkable visible light transparency (Tlum ≈ 95.2%) and solar modulation (△Tsol ≈ 57.2%). Interestingly, PHC‐Gel has superior electrical conductivity, suggesting that PHC‐Gel can be utilized to fabricate wearable signal‐response and temperature sensors. In summary, PHC‐Gel has broad application prospects in energy‐saving smart windows, smart wearable sensors, temperature monitors, infant temperature detection, and thermal management.

Self-adaptive high-temperature gels with long-lasting underwater stability for environmentally tolerant flexible sensors and water-writing papers

“…Particularly, smart gels that can change their optical properties (e.g., fluorescence, structural color, and transparency) by responding to external stimuli (e.g., heat, light, chemicals, and electricity) have attracted great attention. [44][45][46] These responsive gels have become ideal candidates for generating multifunctional information handling models and have been widely used in anti-counterfeiting technology, information encryption and smart windows. [47][48][49][50][51] Interestingly, the prepared PEA-AA-MAm/ IL gel demonstrated an obvious transparency-shifting behavior under the stimulation of different polar solvents.…”

Thermochromic Hydrogels with Adjustable Transition Behavior for Smart Windows

“…Energy conservation and emission reduction have become a global challenge. It has been reported that the building energy consumption accounts for 40% of the total energy, − of which half is consumed by heating, ventilation, and air conditioning . Therefore, improving the energy efficiency of buildings is the key to energy conservation. − …”

Smart Contact Lens for Colorimetric Visualization of Glucose Levels in the Body Fluid

“…Further technological advancements in these sensors have been supported by improvements in wireless communication technology, which facilitate seamless data transmission between the sensors and mobile monitoring devices. Additionally, the advancement of wearable, transparent, , and flexible electrode materials, − alongside the innovation of antimicrobial and biocompatible hydrogels, , has not only maintained the essential transparency of contact lenses but also improved their functional integration, making the lenses comfortable to wear. However, only a few of the electrochemistry-based technologies developed have been commercialized, owing to the following reasons: (1) The existing electrochemical-based smart contact lenses (glucose sensors) generate heat that could damage the tissues of eyes due to the presence of a circuit.…”