Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of OCT. In addition to imaging based on tissue reflectivity, PS-OCT also enables depth-resolved mapping of sample polarization properties such as phase-retardation, birefringent axis orientation, Stokes vectors, and degree of polarization uniformity (DOPU). In this study, PS-OCT was used to investigate the polarization properties of melanin. In-vitro measurements in samples with varying melanin concentrations revealed polarization scrambling, i.e. depolarization of backscattered light. Polarization scrambling in the PS-OCT images was more pronounced for higher melanin concentrations and correlated with the concentration of the melanin granules in the phantoms. Moreover, in-vivo PS-OCT was performed in the retinas of normal subjects and individuals with albinism. Unlike in the normal eye, polarization scrambling in the retinal pigment epithelium (RPE) was less pronounced or even not observable in PS-OCT images of albinos. These results indicate that the depolarizing appearance of pigmented structures like, for instance, the RPE is likely to be caused by the melanin granules contained in these cells.

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The structure of the composite material consisting of the ionic liquid 1-butyl-3-methylimidazolium nitrate (BMINO3) entrapped in a silver matrix was investigated. Entrapment is confirmed by combining thermal analysis and spectroscopic investigations and by comparing physicochemical properties of the genuine ionic liquid and the composite BMINO3@Ag. An organization of the ionic liquid molecules toward the silver surface was observed.

Small-angle X-ray scattering (SAXS) experiments were carried out to investigate systems consisting of silica nanoparticles bridged by imidazolium-based linkers. This characterization method delivers a quantitative description of the efficiency to order nanoparticles obtained from different chemical approaches. Two packing factors were extracted from the SAXS curves, where one characterizes the stacking of the ligands and the other the order of the nanoparticles. The amount of order can be controlled by using different ligands such as mono-and diimidazolium-based ones with different flexibilities or by varying the ligand length.