Constructing core@shell SiO <sub>2</sub>@C-Au multicomponent nanocomposites to enhance conduction and polarization loss capabilities for microwave absorption and antimicrobial
Xiaofeng Gong, Jing Dang, Junxiong Xiao, Xihui Wang, Tianming Jia, Li Yao, Jingliang Yang, Xiaosi Qi, Yunpeng Qu, Wei Zhong
Abstract
Conduction and/or polarization loss play a key role in improving electromagnetic wave (EMW) absorption. In this work, a combined polymerization and high-heat treatment process was utilized to efficiently fabricate core@shell structure SiO<sub>2</sub>@C adopting SiO<sub>2</sub> nanospheres as a hard template. The acquired SiO<sub>2</sub>@C nanocomposites displayed unsatisfied EMW absorption performances with minimum reflection loss value of -34.92 dB at 6.35 mm, and effective absorption bandwidth value of 3.20 GHz at 4.83 mm, respectively. In order to further comprehensively boost its MAPs, a facile self-assembly strategy was adopted to load Au nanoparticles on the outer surface of SiO<sub>2</sub>@C nanospheres, constructing core@shell SiO<sub>2</sub>@C-Au multicomponent nanocomposites (MCNCs). By regulating the volume of Au nanoparticles, different Au contents of SiO<sub>2</sub>@C-Au MCNCs could be selectively produced in high efficiencies. The obtained outcomes demonstrated that the SiO<sub>2</sub>@C-Au MCNCs presented improved properties including EMW attenuation, impedance matching, conduction loss and polarization loss with increasing the content of Au nanoparticles. Thanks to the introduction of conductive Au nanoparticles and excellent interfacial effects, the SiO<sub>2</sub>@C-Au MCNCs presented the greatly improved antimicrobial and EMW absorption performances including strong absorption, wide bandwidth and small thicknesses. Consequently, this finding offered a novel strategy to construct core@shell SiO<sub>2</sub>@C-Au MCNCs, which simultaneously boosted conduction and polarization loss capabilities for EMW absorption.