in: ACS Applied Materials & Interfaces (2017) 44181
The supra-molecular structure essentially determines the properties of organic thin films. Therefore, it is of utmost importance to understand the influence of molecular structure modifications on supramolecular structure formation. In this paper we report about the influence of the length of an alkylic spacer between a thiazole chromophore and a polar anchor group on the solid state phases that can be accessed. Therefore, we characterize their corresponding supra-molecular structures, thermodynamic, absorption and fluorescence properties. Particularly, the polarization-dependence of the fluorescence is analyzed to deduce molecular orientations and their possible changes after annealing, i.e. to characterize the thermodynamic stability of the individual solid state phases. Since the investigated thiazoles are amphiphilic, the different solid state phases can be formed and controlled by means of the Langmuir-Blodgett (LB) technique. This technique also allows to deduce atomistic supra-molecular structure motives of the individual solid phases and to characterize their thermodynamic stabilities. Utilizing the LB-technique we demonstrate that subtle molecular changes, like the variation in spacer length, can yield entirely different solid state phases with distinct supra-molecular structures and properties.