Geopolymers have emerged as a promising alternative to ordinary cement due to their attractive physical and thermal properties. The typical compressive strength of geopolymers and their composites is usually limited to around 80 MPa, therefore they should be further strengthened for wider applications, such as ultrahigh strength concrete and bone replacement. This paper presents a facile method for enhancing the compressive strength by incorporating silicon carbide particles (SiC p ) and silicon carbide whiskers (SiC w ) into a geopolymer matrix via the geopolymerization of metakaolin (MK). The effects of the reinforcement of SiC p and SiC w on the microstructure, thermal properties and compressive properties of the composites were investigated. The SEM images showed that both SiC p and SiC w were well dispersed in the geopolymer matrix. Due to the bridging effect among the SiC w particles, the silicon carbide whisker/geopolymer (SiC w /GP) composites possessed higher porosity and lower density, and thus lower thermal stability and thermal conductivity as compared with the silicon carbide particle/geopolymer (SiC p /GP). The mechanical tests showed that the compressive strength of SiC p /GP composites increased with the increase of SiC p concentration. With an optimum concentration of 10 wt % of SiC p , the compressive strength of the composite was enhanced to 155 MPa, corresponding to a 100% increase as compared with the unfilled geopolymer.
In recent years, water harvesting in arid or semi-arid areas has gained increasing attention. Inspired by the fog harvesting ability of hydrophobic–hydrophilic surfaces associated with Namib desert beetles, considerable effort has been expended in creating such bionic surfaces. However, designing a surface with excellent water harvesting, superamphiphobic, and water/oil self-cleaning properties remains challenging. Herein, an innovative hybrid consisting of a superamphiphobic surface combined with hydrophilic/hydrophobic particles is fabricated by a facile method. This hybrid surface exhibits a praiseworthy drop nucleation effect, high removal efficiency, excellent water collection efficiency, and commendable water/oil self-cleaning performance. The surface’s water/oil wettability, condensation properties, water collection rate and its dependence on the relative humidity and fog flow velocity were systematically investigated. The results obtained strongly indicated that the proposed hybrid superamphiphobic surface exhibits enhanced water drop condensation and water collection performance. In fact, the hybrid superamphiphobic surface doped with silicon carbide particles wrapped with an acrylic acid polymer emulsion (SiC@PAA) exhibited a better water harvesting effect, with a water collection rate more than double that of the nano-SiO2 superamphiphobic surface. The findings of this work are considered instrumental to the further design and implementation of hybrid superamphiphobic surfaces for cost-efficient atmospheric water harvesting.
危险品化学品经营许可证（带存储）