Fabrication of super-hydrophobic copper mesh by liquid oxidation and vapor silylation

Super-hydrophobic copper mesh was fabricated by liquid oxidation using K2S2O8 as oxidant and followed by vapor silylation with hexamethyldisilazane (HMDS). The preparation process was optimized with respect to four factors. The samples were characterized by Water Contact Angle (CA), XRD, FTIR, respectively as well as evaluated by oil-water separation test. The obtained optimum preparation condition is a K2S2O8 concentration of 0.145 mol·L-1 , a oxidation time of 60 min, a calcaination temperature of 300 °C and a silylation temperature of 190 °C, under which the highest CA can achieve 154°. XRD and FTIR characterizations demonstrate the reaction result of the oxidation of CM to form OCM and of the silylation of OCM to form SOCM, respectively. CM, OCM and SOCM are shown to be low hydrophobicity, hydrophilicity and high hydrophobicity (CA = 154°), respectively. Three samples possess a oil-water (methylbenzene-water) separation ratio of 45.6%, 3.3% and 99.9%, respectively. The reusing experiments for methylbenzene, chloroform and kerosene indicate that SOCM can be utilized for 30 cycles and retains an oil-water separation efficiency of at least 98% for any one oil. It suggests that SOCM has an excellent hydrophobicity, which results from the vapor silylation as a vesatile method for modifying the copper mesh.