Nanotexturing of plasma-polymer thin films using argon plasma treatment

Plasma-polyaniline films are treated by argon plasma in order to obtain nanostructured surfaces. The polymer deposition and its subsequent treatment are realized in a low pressure microwave reactor. The effects of several operating conditions, i.e., discharge power, argon pressure, processing time and substrate bias on the chemical and morphological structure of the obtained layers are examined. The chemical structure of the polymer is characterized using Fourier Transform Infra-Red spectroscopy whereas the film morphology is determined by Atomic Force Microscopy. The results show that the density and the dimensions of the nanostructures can be finely tuned by the plasma parameters. Low argon flow rate or microwave power, short treatment time and the use of substrate polarization yield high structured surfaces. We show that the formation of the nanodots is mainly ion-dependent according to the ion energy and the ion flux. Concerning the chemical structure of treated films, a moderate destruction of aromatic character and a partial loss of amine groups are observed.