Bio-inspired modification of silicon carbide foams for oil/water separation and rapid power-free absorption towards highly viscous oils

Abstract A bio-inspired strategy for the fabrication of superhyrophobic silicon carbide (SiC) ceramic foams (SCFs) using commercially available melamine foam (MF) as the template and vinyl-containing hyperbranched liquid polycarbosilane (VHPCS) as the binder was developed. The pre-oxidation process and crystallization degree during the sintering were monitored by Fourier transform infrared spectroscopy and X-ray diffraction. A plausible reaction was proposed and the thermogravimetry analysis results indicated that VHPCS was more suitable for the adhesive agent of SiC powders. By optimizing the mass ratio of VHPCS and SiC, a maximum compression strength of 1.25 MPa for SCFs was achieved with a low density of 0.514 g/cm3 and only 6.72% of volume shrinkage. The obtained SCFs exhibited rapid power-free absorption towards highly viscous oils after a biomimetic surface modification with n-octadecylamine (ODA). It took only 22 s for the complete absorption of 200 μL ultra-high viscosity oil (5000 mPa s). A probable mechanism for the rapid absorption of viscous oil had been revealed and the decoration of low-surface-energy molecules together with the distinct porous structure were regarded as the critical factors.