Printable Thermochromic Hydrogel‐Based Smart Window for All‐Weather Building Temperature Regulation in Diverse Climates

Abstract

Thermochromic smart windows are widely developed to modulate building energy exchange to save building energy consumption. However, most smart windows have fixed working temperatures, moderate energy‐saving efficiency, and are not suitable for diverse (cold and hot) climates. Here smart windows with strong temperature modulation over a broad range of hydrogels with adjustable transition temperatures for all‐weather building temperature regulation in different climates are reported. Thermochromic poly(N‐isopropylacrylamide‐co‐N, N‐dimethylacrylamide) hydrogels, with lower critical transition temperatures ranging from 32.5 to 43.5 °C, are developed for smart windows with solar modulation up to 88.84% and intrinsic transmittance up to 91.30% over full spectrum without energy input. Simulated indoor investigations are performed in different cities from 23 °N to 39 °N from winter to summer. The results indicate that smart windows have a strong solar modulation in summer to reduce indoor temperature up to 7.3 °C and efficient heat conservation in winter to save energy up to 4.30 J m−3, in comparison to glass windows. Smart windows with grid patterns and Chinese kirigami are fabricated by using 3D printing of the hydrogels to achieve both solar modulation and light incidence. The strategy offers an innovative path for thermochromic smart windows for low carbon economy.

Colored Polymeric Films with a Bilayer Porous Design for Efficient Subambient Radiative Cooling

“…A coagulation bath consisting of a DMF–water blend (v/v = 3:7) was used to solidify the printed structures (Figure g). 3D printing is a versatile rapid prototyping technology that allows for the fabrication of complex three-dimensional structures based on digital models. , In the case of the CPRCs, the printing process involved the immediate phase separation of the PVC/DMF solution upon contact with the coagulation bath, which resulted in the efficient solidification of the printing ink. By repeating the printing process layer by layer, diverse and well-designed patterns could be created by using the 3D printing method.…”

An Ultrafast, Energy‐Efficient Electrochromic and Thermochromic Device for Smart Windows

“…[4] Among smart windows, thermochromic windows can dynamically adapt to variations of solar and thermal radiation without energy consumption, and are drawing enormous attention recently. [5] Nonetheless, existing thermochromic windows are generally limited to a single color, namely white, which fails to capture the aesthetic preferences of individuals in contemporary society. By combining thermochromic devices with colorful yet energyefficient electrochromic devices (ECDs), it becomes feasible to achieve multiple objectives such as enhancing building/vehicle energy efficiency, preserving privacy, and improving aesthetics.…”

3D printed microstructured ultra-sensitive pressure sensors based on microgel-reinforced double network hydrogels for biomechanical applications

“…7,8 Polymer hydrogels are biomimetic biofunctional materials of a 3D cross-linked hydrophilic polymer network containing a large amount of water with adjustable physical, chemical, mechanical and electrical properties. 9–11 Therefore, polymer hydrogels have emerged as ideal materials for wearable flexible electronic devices. For application of flexible sensors in human health monitoring, such as monitoring pulse 12,13 and respiration, 14,15 and during gaiting, 16,17 it is necessary to develop hydrogels with excellent mechanical properties, sensitivity and processibility.…”