Preparation and characterization of polymeric materials preventing bacterial adhesion

Biofilms are three-dimensional protective matrices formed by microorganisms adhering to living or non-living surfaces, composed of extracellular macromolecules such as proteins, polysaccharides, and nucleic acids. These structures enable microorganisms to meet their nutritional needs, protect themselves from chemical agents, and establish favorable microenvironments. In particular, biofilms that persist on equipment surfaces in fields such as the food and pharmaceutical industries, medical devices, and water systems lead to significant contamination problems. This thesis study aimed to synthesize functional filler materials that inhibit bacterial adhesion and biofilm formation, and to develop composite materials incorporating these fillers. For this purpose, various modified synthetic layered double hydroxides (LDHs) and organosilicon-based polyhedral oligomeric silsesquioxane (POSS) compounds were synthesized, and their structural features were confirmed through FTIR, XRD, BET, SEM, TGA, and DSC analyses. Based on antimicrobial activity tests, effective synthesized fillers against Gram-positive and Gram-negative bacterial strains were incorporated into unsaturated polyester resin (DPes) and polypropylene (PP) matrices as representatives of thermoset and thermoplastic systems, respectively. The formation of biofilms on the surface of suitable materials was quantitatively assessed using fluorescence-based microplate analysis. In addition, the mechanical properties of the selected materials were also investigated through texture analysis and DMA. For the first time in this study, the exfoliated LDH filler (BA-LDH-PC), which possesses a boron-phosphorus cluster-like structural geometry, was synthesized and characterized, demonstrating the highest antibacterial activity. Among the composites, DPes-based material (M3) containing 5 wt% and PP-based material (P3) containing 7 wt% of this filler exhibited the lowest levels of biofilm formation on their surfaces. Mechanical analysis revealed that M3 exhibited a ductile behavior with low modulus and strength, while P3 exhibited a rigid structure with high modulus and tensile strength. This study is the first to demonstrate that the developed fillers can be used in the production of biofilm-inhibiting composite materials based on different polymer matrices. The results indicate that the developed materials offer high application potential for use on equipment and food packaging surfaces in food production facilities, as well as in hygiene-critical environments and shared public areas such as lavatories, showers, and toilets.