Abstrakt

Autogenous chemical and structural transition and the wettability of electro polymerized PANI surface

  Mr.Yoganandan Govindaraj 

 Polyaniline (PANI) was electrochemically deposited on mild steel substrate. Autogeneous transition in physical and chemical structure in nanometer scale showed anomalous ehaviour in the wettability of the surface. Surface morphology showed the formation of nano dentritic structure on naturally aged PANI coated surface. Spontaneous changes in the backbone of the polymer was also observed due to oxidation. Electrochemical impedance spectroscopy results exhibited a continuous increase in resistance of the PANI layer due to self-oxidation. Surface topography of naturally aged PANI surface was more smooth and homogeneous as compared to that of as pereaed condition. Water contact angle measurement using different liquids showed the surface energy of PANI has decreased >70% after 30 days of exposure in the ambient environment. A gradual increase in water contact angle of >1500 on electro polymerized PANI surface was observed over the period indicated superhydrophobic surface. A self-assembled one layer formation was explained with the help of SEM, FT-IR, Raman, XPS and contact angle measurements. The findings are explained based on the cassie-Baxster mechanism of micro-nano-cluster formation over PANI surface during continuous exposure.