Structure control of a zinc tetraphenylporphyrin thin film by vapor annealing using fluorine containing solvent

he solvent vapor annealing (SVA) technique is one of the useful post processing techniques of a thin film, which is an alternative technique of the thermal annealing one. SVA has a great advantage that the molecular rearrangement in the film is made moderately by employing an appropriate solvent without the sample heating. The moderate processing is expected to yield a benefit that the molecular coalescence would be suppressed, which would readily keep the continuous surface topography of the film during the annealing, and another benefit that a metastable structure would be obtained. To make the best use of the SVA-specific characteristics, in the present study, a material having a metastable structure is chosen. The sample is zinc tetraphenylporphyrin (ZnTPP) that yields a metastable triclinic crystal structure, which can easily be converted to a monoclinic crystal structure by thermal annealing. A triclinic-structure film of ZnTPP by the combination of a wet process and the thermal annealing has thus never been reported. By choosing a fluorine-containing solvent, which has a low affinity to ZnTPP, a triclinic-structure film has first been obtained by a wet process while the surface continuity is protected

Fluorous Property of a Short Perfluoroalkyl-Containing Compound Realized by Self-Assembled Monolayer Technique on a Silicon Substrate

Fluorous properties represented by water-and-oil repellency are perfluoroalkyl (Rf) compound-specific characteristics, which are widely used for surface coating of glass, electronic devices and textiles for preventing water and grease fouling. According to the stratified dipole-arrays (SDA) theory, the minimum Rf length of (CF₂)₇ is theoretically necessary for realizing fluorous properties. Unfortunately, however, production of compounds involving this chemical unit is strictly banned because of concerns of environmental pollution, which is a big dilemma. Here, we show that the fluorous properties can be realized by self-assembled monolayer (SAM) even with a short Rf-containing compound, since the SAM technique makes the best use of the self-aggregation property of the Rf groups, and it readily makes the molecules immobile