A two‐dimensional polymer synthesized at the air/water interface

A trifunctional, partially fluorinated anthracene?substituted triptycene monomer is spread at the air/water interface into a monolayer, which is transformed into a long?range ordered 2D polymer by irradiation with a standard ultraviolet lamp using 365 nm light. The polymer is analyzed by Brewster angle microscopy directly at this interface and by scanning tunneling microscopy measurements and non?contact atomic force microscopy (nc?AFM), both after transfer from below the interface onto highly oriented pyrolytic graphite and then into ultra?high vacuum. Both methods confirm a network structure, the lattice parameters of which are virtually identical to a structural model network based on X?ray diffractometry of a closely related 2D polymer unequivocally established in a single crystal. The nc?AFM images are obtained with unprecedentedly high resolution and prove long?range order over areas of at least 300 ? 300 nm2. As required for a 2D polymer, the pore sizes are monodisperse, except for the regions, where the network is somewhat stretched because it spans over protrusions. Together with a previous report on the nature of the cross?links in this network, the structural information provided here leaves no doubt that a 2D polymer has been synthesized under ambient conditions at an air/water interface