We have studied the interaction between an organic molecule with a high dipolar moment (CH2CHCN) and an evaporated nickel surface, by UPS HeI and Metastable De-excitation Spectroscopy (He 23S). In chemisorption from vapour phase, CH2CHCN molecules are bound by the nitrile groups, as revealed by the absence of the nitrogen lone-pair peak in MDS and UPS spectra. On the other hand, when the interaction is performed at the cathode of an electrochemical cell, we observe a very strong nitrogen lone-pair peak. The polar molecule has been flipped by the intense electric field of the cathodic double layer and the molecule is bound through the -CH2 extremity.

A thin film of polyacrylonitrile, deposited by electropolymerisation onto a cathode of oxidizable metal (Ni, Fe,…) is subjected to heat treatment under vacuum (1 h, 600°C, 10−5 Pa). This procedure allows us to obtain a film of pyrolytic carbon, which retains the essential properties of a polyacrylonitrite film: homogeneity, purity, and a strong adherence to the metallic substrate.