Investigation of biological and mechanical properties of liquid crystalpolymer membranes

In this thesis project, polymer matrix liquid crystal-based composite membranes were prepared, and their antimicrobial and mechanical properties were investigated. Considering the properties of liquid crystal materials that make composite membranes, It is known that they are organic materials formed in different phases during the transition of matter from solid to liquid state and have at least five carbon structures. While their molecular arrangement resembles the regular state of solids, they can physically show fluidity like liquid materials. Thermotropic liquid crystals, which are liquid crystals divided into two main classes among themselves, change phase as a function of temperature and are generally used in technological applications such as electronic books and screens; Lyotropic liquid crystals, which show phase change depending on their dissolution in water as well as temperature, are found in the structures of human DNA, cholesterol, and lipids. Lyotropic liquid crystals, mostly used in biological and medical fields, are called 'amphiphile molecules' because they have a head and tail. Liquid crystals, frequently encountered in membrane applications, can also be used by forming composites with polymer materials used for biological applications. Studies on polymer matrix-liquid crystal composite membranes have also increased in recent years. In this thesis study, unlike the studies in the literature, In addition to the liquid crystal-polymer membrane formation, it is aimed to examine the effects on the biological properties of the membranes formed by adding Anticoagulant Citrate Dextrose (ACD) and Cinnamaldehyde (CA) additives to the system. The effects of the additives on the formed membranes were visualized with various microscopes, and biological evaluations such as water tests, surface contact angle measurements, and thromboplastin measurements were made. The biocompatibility of membranes with thromboplastin obtained from rabbit blood and albumin obtained from rabbits, which has a standard feature with human blood due to its high fibrinogen level, were investigated. As a result of the tests, it was observed that the water holding capacity decreased, but the surface contact angle increased as the mass concentration of the CA additive in the membranes containing 5:5 by mass liquid crystal and polymer increased. As the mass concentration of the additive increased, it was observed that the thromboplastin spread over the surface, and in the blood coagulation indices (BCI), it was observed that the sample containing 3% by mass CA had the highest BCI value. When the samples containing ACD additive are examined, it is seen that the water holding capacity and surface contact angle measurements are similar. In contrast, the sample containing 2% ACD additive by mass has the highest BCI value.