LOW-ENERGY ELECTRONIC STATES RELATED TO CONTACT ELECTRIFICATION OF PENDANT-GROUP POLYMERS - PHOTOEMISSION AND CONTACT POTENTIAL DIFFERENCE MEASUREMENT

Low-energy electronic states, 3-6 eV below the vacuum level, relevant to contact electrification of pendant-group polymers were investigated by means of photoemission and contact potential difference (CPD) measurements under atmospheric conditions. As a result, it was shown that the thresholds of photoemission of the polymers are related to their highest occupied molecular orbital (HOMO) levels derived from modified neglect of diatomic overlap (MNDO) molecular orbital calculation, and that the thresholds exist near the energy corresponding to their work function inferred from CPD measurement. Furthermore, it was found that the contact electrification of the polymers is related to their threshold of photoemission. These results are interpreted in terms of a molecular ion model proposed by Duke et al. [Phys. Rev. B 18 (1978) 5717].