Investigation of partially deuterated organic multilayers by means of X-ray and polarized neutron reflectometry

The investigation of organic multilayer structures prepared by means of the Langmuir-Blodgett (LB) technique is found to be complex due to molecular intermixing arising during the preparation procedure. To fully understand the intermixing processes, not only the X-ray reflectivity, but also neutron reflectivity measurement, must be carried out. It has been already reported 1,2] that it is impossible to investigate the chain-chain intermixing process only by X-ray reflectivity. This due to the lack of electron density contrast within the mixed materials. Sufficient contrast, however, can be achieved by applying neutron reflectivity [3,4], because of the possibility to generate a strong contrast between chains by the deuteration process which only slightly changes the material properties. On the other hand, X-ray reflectivity provides sharp layer structure peaks and Kiessig oscillations from which the period of structure and total thickness of film system can be determined.