Preparation of low contact angle TiO2–polyester “core-shell” emulsions employing ultrasonic irradiation

TiO 2 –polyester composite emulsions with low contact angle on steel sheet were prepared in a “core-shell” structure employing ultrasonic irradiation. The cluster size of the TiO 2 was reduced and the nano-particles were well dispersed. The molecular weight of the polyester resin initially decreased, then increased forming the characteristic core-shell structure. This was a clear indication that the TiO 2 particles were coated with the recombined polyester as a direct result of the ultrasonic irradiation. The contact angle of the emulsion was reduced which indicated that the wettability of the emulsion was improved without the addition of chemical additives. These results suggest the possibility of producing low contact angle coatings by mechanical way.