Ultrasonic-assisted synthesis of hydrophobic magnesium hydroxide nanoparticles

In this paper, with the aid of ultrasonic irradiation, hydrophobic magnesium hydroxide (MH) nanoparticles were synthesized via one-step precipitation reaction, in which the reactant solutions were simultaneously added into an organic phase instead of an aqueous phase. Tween 80 was added as a stabilizer, dispersant and surface modifier. During this synthesis process, ultrasonic irradiation could restrict the crystal growth of MH on each lattice plane and improve hydrophobicity of MH nanoparticles. Addition of Tween 80 was favourable to obtain smaller sized MH nanoparticles with even crystal growth and better dispersibility, and to further enhance the hydrophobic property of MH nanoparticles based on its bridging function between surface of MH nanoparticles and aliphatic compounds in organic phase. In addition, the morphology and the properties of obtained MH nanoparticles were characterized by XRD, FESEM, FT-IR, TGA, respectively. The improved hydrophobicity and dispersibility of surface modified MH nanoparticles were also verified by the sedimentation tests.