Preparation of superhydrophobic and oleophobic diamond nanograss array

The paper reports on the fabrication of superhydrophobic boron-doped diamond nanograss surfaces. The boron-doped diamond nanograss array (BDD NG) was prepared simply by reactive ion etching (RIE) with oxygen plasma of highly boron-doped (the boron doping level is 8 x 10(19) B cm(-3)) polycrystalline diamond electrodes. Depending on the RIE conditions, substrates with different nanograss densities can be prepared. Chemical functionalization of the NG array surface with octadecyltrichlorosilane (OTS) or 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (PFTS) led to the formation of superhydrophobic surfaces. Under optimized conditions, BDD NG surfaces with contact angles as high as 160 degrees and quasi null hysteresis (< 2 degrees) can be reached. A water droplet deposited on the surface tends to roll off when the NG surface was tilted by a few degrees. Furthermore, the BDD NG array chemically modified with PFTS displays oleophobic properties. A contact angle of 94 degrees was measured for hexadecane. The resulting surfaces were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, and contact angle (CA) measurements.