[Hydrophilic Surface Modification of Polydimethylsiloxane with UV/Ozone Treatment]

The UV/ozone surface treatment was a simple and low cost hydrophilic modification method. In this paper，UV/ozone treatment is utilized to hydrophilize the surface of PDMS and the results are compared. Contact angle is applied to estimate the effect and stability of the modified surfaces. The results show that the contact angle is around 60° on the PDMS surface with UV/ozone treatment after 12 hours, and it can maintain the surface hydrophilicity in two weeks under ambient atmosphere. The results of FTIR spectroscopy indicate that many chemical functional groups of PDMS surface have been changed with UV/ozone modification, —CH3 hydrophobic group gradually decrease over time, —OH and Si—OH hydrophilic groups increase obviously, and the characteristic peaks of SiO2 gradually appear. Through SEM/EDS analysis, it has been found that the major constituent of the surface of PDMS is SiO2 after the surface modification. These results demonstrate that the more hydrophilic groups and the glass-like SiOx layer are formed on the PDMS surface modified with UV/ozone, which enhance the surface hydrophilic and minimize the hydrophobic recovery.