Abstract
Molecular orientation in Langmuir-Blodgett (LB) films of newly synthesized ternary comb copolymers with N-vinylcarbazole (NVCz) and fluorinated side-chain was investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC) surface pressure-area (pi-A) isotherm, out-of plane and in-plane XRD, and atomic force microscopy (AFM). The results were compared with those of three-dimensional crystals. In the bulk state, these ternary comb copolymers formed side-chain crystals, which exhibited two-dimensional lattice spacing of 4.2 and 5.0 A. From the results of the DSC measurements, sharp melting peaks appeared in the relatively lower temperature side in the thermograms. This result supported the formation of side-chain crystals in the synthesized ternary comb copolymers. These copolymers formed extremely condensed monolayers on the water surface. From the out-of plane XRD measurements of multilayers on solids, formation of highly ordered layer structure were confirmed. From the in-plane XRD measurements of these multilayers, the two-dimensional lattice structures of ternary comb copolymer films containing NVCz units were different from that of their bulk state. These structural changes may be caused by the pi-pi interaction between the carbazole rings comparable with the van der Waals interaction between fluorocarbons.
