trans -Stilbene aggregates and crystallites in polystyrene films: microscopy and spectroscopy studies.

Solid and liquid stilbene forms were characterized using a range of techniques, including atomic force microscopy, coherent anti-Stokes Raman scattering microspectroscopy and optical spectroscopy. The obtained experimental results were analyzed by means of quantum chemical calculations and using a non-negative matrix factorization algorithm. It was confirmed that pure cis -stilbene formed a homogeneous fluid film on a glass substrate, whereas pure trans -stilbene formed crystals. Mixtures of trans -stilbene and polystyrene were shown to form stable solid films, which were non-homogeneous on the microscopic scale: stilbene molecules self-organized into microcrystals, which floated on the surface of polystyrene glass.