948: The Role of PDMS Topology in Designing Hydrophobic Waterborne Polyurethane Coatings with Low Surface Energy

The Role of PDMS Topology in Designing Hydrophobic Waterborne Polyurethane Coatings with Low Surface Energy

M. Çiğdem Uçar^a,b, Ekin Berksun^a,b, Serkan Ünal^a,b,*

^aFaculty of Engineering and Natural Sciences, Material Science and Nano Engineering,

Sabanci University, Tuzla, Istanbul, Turkiye

^bIntegrated Manufacturing Technologies Research and Application Center & Composite Technologies Center of Excellence, Sabanci University, Pendik, Istanbul, Turkiye

*E-mail : serkan.unal@sabanciuniv.edu 

Hydrophobic soft matter plays a crucial role in the development of coatings requiring flexibility, water resistance and tunable properties, making it valuable in industries such as wood, construction, automotive, electronics and textiles. Waterborne polyurethane dispersions (WPUs) are environmentally friendly colloidal systems that contribute to sustainable and safe coating applications due to their low volatile organic compound (VOC) emissions. However, their inherently hydrophilic nature limits their water resistance in some applications. This study explores the synthesis and characterization of novel WPUs modified with polydimethylsiloxane (PDMS) oligomers of varying topologies to enhance hydrophobicity while maintaining mechanical integrity. The effect of incorporating linear, pendant or branched PDMS segments at different concentrations into the polyurethane backbone is investigated to optimize the balance between topology, hydrophobicity and mechanical flexibility. The resulting coatings are evaluated through static and dynamic contact angle measurements and water absorption tests to determine the optimal PDMS topology and content for achieving both high durability and low wettability.