Zhong Shenjie, Yuan Shuaixia, Zhang Xun, Zhang Jiawen, Xu Lang, Xu Tianqi, Zuo Tian, Cai Ying, Yi Lingmin
Institute of Advanced Functional Coatings, College of Textile Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
Engineering Research Center for Eco-Dyeing & Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, P. R. China.
ACS Appl Mater Interfaces. 2023 Aug 23;15(33):39807-39817. doi: 10.1021/acsami.3c06178. Epub 2023 Aug 9.
The development of new structural materials for passive daytime radiative cooling (PDRC) of buildings will significantly reduce global building energy consumption. Cellulose aerogels are potential PDRC materials for building cooling, but the cooling performance and mechanical strength of cellulose aerogels are considered as challenges for their practical applications. Herein, a bio-inspired hierarchically structured cellulose aerogel (HSCA) was fabricated through an assembly strategy assisted by a high-voltage electrostatic field. The HSCA possesses outstanding PDRC performance and moderate mechanical strength owing to aligned hierarchical porous network microstructures reinforced with -assembled crystalline cellulose nanofibers. Promisingly, the HSCA achieves a max cooling temperature of 7.2 °C and exhibits 1.9 MPa axial compressive strength. There was no significant cooling performance degradation after the hydrophobically modified HSCA was placed outdoors for 3 months. A simulation of potential cooling energy savings shows that by using HSCA as the building envelopes (side wall and roof), it can save 52.7% of cooling energy compared to the building baseline consumption. This new strategy opens up the possibility of developing advanced functionally regenerated cellulose aerogel, which is expected to provide a revolutionary improvement in aerogel materials for building cooling.
开发用于建筑物被动式日间辐射冷却（PDRC）的新型结构材料将显著降低全球建筑能耗。纤维素气凝胶是用于建筑制冷的潜在PDRC材料，但纤维素气凝胶的冷却性能和机械强度被认为是其实际应用面临的挑战。在此，通过高压静电场辅助的组装策略制备了一种受生物启发的分级结构纤维素气凝胶（HSCA）。由于由自组装结晶纤维素纳米纤维增强的排列有序的分级多孔网络微结构，HSCA具有出色的PDRC性能和适度的机械强度。令人鼓舞的是，HSCA实现了7.2℃的最大冷却温度，并表现出1.9MPa的轴向抗压强度。疏水改性的HSCA在户外放置3个月后，冷却性能没有明显下降。潜在冷却节能模拟表明，与建筑基线能耗相比，使用HSCA作为建筑围护结构（侧壁和屋顶）可节省52.7%的冷却能耗。这种新策略为开发先进的功能再生纤维素气凝胶开辟了可能性，有望为建筑制冷的气凝胶材料带来革命性的改进。
