Structural Characterization of Self-Organized Mono- and Multilayers of Partly Fluorinated Polydialkoxyphosphazenes at the Air/Water Interface

We report studies of the collapse of monolayers of mesomorphic poly[bis-(2,2,3,3,4,4,5,5-octafluo-ropentoxy)phosphazene] and poly[bis-(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptoxy)phosphazene]. The structure of the films has been examined at different stages of the collapse process by synchrotron grazing incidence X-ray diffraction. Surface pressure–surface area isotherms show that these films undergo a stepwise collapse with formation of multilayers. Grazing incidence X-ray diffraction reveals only one diffraction peak for the monolayer as well as for multilayers of the two polymers studied, which corresponds to an in-plane interchain spacing d = 15.2±0.1°Å and 17.6±0.5°Å, respectively. The in-plane correlation length ξxy reaches ca. 500 Å for PFP-C5 (33 macromolecules) and ca. 400 Å for PFP-C7 (23 macromolecules), implying a certain mesoscale order similar to a quasi-long-range one