Orientation effects of PTFE nanolayers upon the nematic 5CB

Planar nematic layers of 5CB oriented by 'sliding on' nanolayers of PTFE were studied by electro-optic methods. Deposited layers were characterized by AFM and spectroscopic ellipsometry. It was found that at 100 degrees C presumably single PTFE chains (4 nm thickness) are deposited. By ellipsometry measurements c. 0.1 degrees pretilt angle of the nematic layer was determined. In planar nematic layers low frequency flexoelectric splay oscillations were excited. An overall 1/f shape of the oscillation spectrum was found in the range 1 to 1000 Hz, giving no evidence of a surface viscosity effect in this range.