Liu Wenkai, Ju Shenghong
China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China.
J Phys Chem B. 2024 Mar 28;128(12):2972-2984. doi: 10.1021/acs.jpcb.3c07445. Epub 2024 Feb 14.
In this work, the effects of the Si/Al ratio and moisture content on thermal transport in sustainable geopolymers have been comprehensively investigated by using the molecular dynamics simulation. The thermal conductivity of geopolymer systems increases with the increase of Si/Al ratio, and the phonon vibration frequency region, which plays a major role in the main increase of its thermal conductivity, is 8-25 THz, while the rest of the frequency interval contributes less. With the increase of moisture content, the thermal conductivity of geopolymer systems decreases at first, then increases, and finally stabilizes, which is contrary to the changing trend of the porosity of the system. This is mainly because the existence of pores leads to phonon scattering during thermal transport, which, in turn, affects the thermal conductivity of the system. When the moisture content is 5%, the thermal conductivity reaches a minimum value of about 1.103 W/(m·K), which is 40.2% lower than the thermal conductivity of the system without a water molecule. This work will help to enhance the physical level understanding of the relationship between the geopolymer structures and thermal transport properties.
在这项工作中，通过分子动力学模拟全面研究了硅铝比和含水量对可持续地质聚合物热传输的影响。地质聚合物体系的热导率随硅铝比的增加而增加，其热导率主要增加部分中起主要作用的声子振动频率区域为8 - 25太赫兹，而其余频率区间贡献较小。随着含水量的增加，地质聚合物体系的热导率先降低，然后升高，最后稳定，这与体系孔隙率的变化趋势相反。这主要是因为孔隙的存在导致热传输过程中的声子散射，进而影响体系的热导率。当含水量为5%时，热导率达到约1.103 W/(m·K)的最小值，比不含水分子体系的热导率低40.2%。这项工作将有助于从物理层面加深对地质聚合物结构与热传输性质之间关系的理解。
