Preparation of water-repellent thin film by RF pulse-modulated plasma CVD using C2H2F2 gas

The influences of pulse modulation on water-repellent film preparation have been investigated in RF pulse-modulated plasma CVD using C2H2F2 and Ar mixture gases for an improvement of transparency with keeping repellency. In the case of high total pressure of 100 Pa, transparency of the prepared films decreased from 90 to 50% with increasing duty ratio of RF power, while the water contact angle increased from 120 to 160°. On the other hand, in the case of low-pressure of 25 Pa, these properties of the prepared films were almost independent on the duty ratio, keeping high transparency with more than 90% and normal hydrophobic nature with the contact angle of about 100°.