I have tried to coat the magnetic core with TEOS using ultrasonic bath. However, it turned that my product was hardly seperated by external magnet because the interaction with the dispersant (water) was to strong. I just assumed that its because the hydrogen bonding of between the Fe3O4-SiO2 and water was to strong.
My question is, is it right because of the hydrogen bonding? And how to solve it if I still want to use the ultrasonic bath?
Thank you.