The Effect of Silica Powder Based on Methyltrimethoxysilane and Silica Sand as a Hydrophobic Material

In this research, a hydrophobic surface has been successfully created using a mixture of silica sand and methyltrimethoxysilane (MTMS) precursor. This research aims to determine the effect of varying the volume of MTMS on the hydrophobic surface. The MTMS as silica precursor was synthesized with Stöber method. The variation used is the volume of the MTMS precursor, while the silica from silica sand is made constant. The volume variation of the MTMS precursor is 9.5 ml, 19 ml, 28.5 ml and 38 ml. The MTMS/SiO2 composite which has been synthesized then get mixed with steel ship paint and coated on the steel plate surface as a topcoat. The MTMS/SiO2 composite was further characterized by X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Water Contact Angle (WCA), and Atomic Force Microscope (AFM) which were employed to investigate crystal structure, morphology of particle, hydrophobicity on a surface, and topography of the three-dimensional surface layer respectively. The type of liquid used in the WCA characterization is seawater. XRD characterization results show that silica sand has a quartz phase, MTMS has an amorphous phase and MTMS/SiO2 composite tends to have an amorphous phase. SEM characterization show that the particle size of silica sand that has been mixed with MTMS is around 8 – 20 μm. WCA characterization show that the addition of silica powder on the topcoat increase surface roughness and WCA, so that the steel plate surface has good hydrophobic properties. The highest water contact angle obtained in this research was 109o by seawater.