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212 results on '"Tang, Changyu"'

7. Self-cleaning and self-cooling paper

Author

Tian, Yanpei, Shao, Hong, Liu, Xiaojie, Chen, Fangqi, Li, Yongsheng, Tang, Changyu, and Zheng, Yi

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science
Abstract

The technique of passive daytime radiative cooling (PDRC) is used to cool an object down by simultaneously reflecting sunlight and thermally radiating heat to the cold outer space through the Earth's atmospheric window. However, for practical applications, current PDRC materials are facing unprecedented challenges such as complicated and expensive fabrication approaches and performance degradation arising from surface contamination. Here, we develop a scalable paper-based material with excellent self-cleaning and self-cooling capabilities, through air-spraying ethanolic polytetrafluoroethylene (PTFE) microparticles suspensions embedded within the micropores of the paper. The formed superhydrophobic PTFE coating not only protects the paper from water wetting and dust contamination for real-life applications but also reinforces its solar reflectance by sunlight backscattering. The paper fibers, when enhanced with PTFE particles, efficiently reflect sunlight and strongly radiate heat through the atmospheric window, resulting in a sub-ambient cooling performance of 5$^{\circ}$C and radiative cooling power of 104 W/m$^2$ under direct solar irradiance of 834 W/m$^2$ and 671 W/m$^2$, respectively. The self-cleaning surface of the cooling paper extends its lifespan and keep its good cooling performance for outdoor applications. Additionally, dyed papers are experimentally studied for broad engineering applications. They can absorb appropriate visible wavelengths to display specific colors and effectively reflect near-infrared lights to reduce solar heating, which synchronously achieves effective radiative cooling and aesthetic varieties in a cost-effective, scalable, and energy-efficient way.

Published
2020

9. Mechanical Characteristics of Multi-Level 3D-Printed Silicone Foams.

Author

Yang, Zhirong, Wen, Jinpeng, Zhang, Guoqi, Tang, Changyu, Deng, Qingtian, Ling, Jixin, and Hu, Haitao

Abstract

Three-dimensional-printed silicone rubber foams, with their designable and highly ordered pore structures, have shown exceptional potential for engineering applications, particularly in areas requiring energy absorption and cushioning. However, optimizing the mechanical properties of these foams through structural design remains a significant challenge. This study addresses this challenge by formulating the research question: How do different 3D-printed topologies and printing parameters affect the mechanical properties of silicone rubber foams, and how can we design a novel topological structure? To answer this, we explored the mechanical behavior of two common structures–simple cubic (SC) and face-centered tetragonal (FCT)–by varying printing parameters such as filament spacing, filament diameter, and layer height. Furthermore, we proposed a novel two-level 3D-printed structure, combining SC and FCT configurations to enhance performance. The results demonstrated that the two-level SC-SC structure exhibited a specific energy absorption of 8.2 to 21.0 times greater than the SC structure and 2.3 to 7.2 times greater than the FCT structure. In conclusion, this study provides new insights into the design of 3D-printed silicone rubber foams, offering a promising approach to developing advanced cushioning materials with superior energy absorption capabilities. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Forming Effect of Plasma Treatment on Wettability and Water-Soluble Microneedles of Silicone Rubber.

Author

SUN Li, DENG Ke, WANG Jie, XIAO Haitao, LIU Yingzhi, SHAO Hong, and TANG Changyu

Subjects
WETTING, POLYVINYL alcohol, POVIDONE, SILICONE rubber, HYDROPHILIC surfaces, ADHESION
Abstract

Silicone rubber molds were treated with air plasma and used to prepare polyvinyl alcohol/polyvinylpyrrolidone water-soluble microneedles. The effects of plasma treatment on mold wettability, coating adhesion, micro-needle yield and mechanical properties were discussed. The results showed that plasma treatment could generate polar hydrophilic groups on the surface of the mold, improve the wettability of the mold, the adhesion of polyvinyl alcohol/polyvinylpyrrolidone coating, and elevate the yield rate of micro-needles and the overall mechanical properties. With the prolongation of plasma treatment time, the wettability of the mold, the yield rate of microneedles and the mechanical properties increased increased and then decreased. When the silicone rubber mold was treated with air plasma for 6-8 minutes, water-soluble microneedles with a complete structure, good mechanical property and easy demolding ability could be prepared. [ABSTRACT FROM AUTHOR]

Published
2023
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