A NEW ROUTE TO THIN POLYMERIC, NONCENTROSYMMETRIC COATINGS

A new method for the build-up of non-centrosymmetric multilayers has b een developed, based on physisorption of polyelectrolytes and subseque nt ''pole reversal'' by chemical activation. The multilayers obtained are characterized by UV-Vis spectrometry, X-ray reflectometry, ellipso metry, time-of-flight secondary ion mass spectroscopy and measurements of the zeta-potential. In the chemical activation step of the multila yer build-up, a non-linear optical chromophore is formed, allowing sec ond harmonic generation experiments which corroborate the non-centrosy mmetric structure of the multilayers prepared, as well as demonstratin g the non-centrosymmetry arrangement of the chromophores created.