Bazı liyotropik kiral nematik ve rasemik nematik faz yapılarının küçük açı x-ışını saçılması yöntemiyle belirlenmesi

In this thesis, it was mainly aimed to make a contribution to the chiral induction mechanism of the chiral lyotropic nematic liquid crystals. For this purpose, the lyotropic nematic and chiral nematic liquid crystalline phases were produced using the racemic amphiphiles, potassium N-dodecanoyl-DL-alaninate (DL-KDDA) and DL-serinate (DL-KDDS) and their L-enantiomers, potassium N-dodecanoyl-L-alaninate (L-KDDA) and L-serinate (L-KDDS), respectively. Consequently, the different racemic nematic and chiral nematic phases were characterized by a polarizing light microscope, and their phase diagrams were constructed using laser light diffraction technique. Furthermore, our systems were investigated by the mass density and small-angle x-ray scattering techniques in order to determine the structural differences between the racemic micelles and the chiral micelles of the racemic and intrinsic chiral nematic phases. According to our experimental results and the results on the induced chiral nematic phases in the literature, we proposed a new model on the chiral induction mechanism. This model indicates that there must be (i) a crucial distance and (ii) a critical micelle size in order to obtain chiral induction. In addition, the model shows that the chiral induction does not take place completely as was suggested by pairwise interaction or sterical interaction models in the literature, but through anisotropic chiral interactions via distorted micelles for which a crucial distance between the micelles and a critical micelle size are required.