Improving Hydrophilicity and Adhesion of PDMS through Dopamine Modification Assisted by Carbon Dioxide Plasma

In this paper, the carbon dioxide (CO2) plasma-assisted method was firstly developed for the preparation of dopamine coating polydimethylsiloxane (PDMS). The PDMS films were pre-treated by CO2 plasma at the power of 30–60 W for 5–10 min and then modified by dopamine for 18 h. The results showed that many polar groups such as C-O bonds, C=O bonds, and O-C=O bonds were introduced into the surface of PDMS films, which successfully promoted the formation of poly(dopamine) coating. Finally, the results of contact angle measurements showed that the surface of the plasma-assisted dopamine grafted samples changed from 118° to 64°. The shearing adhesion strength increased from 2.22 N/cm2 to 6.02 N/cm2, almost three times that of the original sample. This method provides a successful strategy for obtaining good poly(dopamine) coating layers on PDMS with strong hydrophilicity and shearing adhesion, which can be widely applied in the fields of medical and adhesive materials.