This lecture covers the synthesis and applications of polymer brushes, focusing on surface-initiated polymerization methods, such as grafting from and grafting onto techniques. It discusses the challenges, architectures, and post-polymerization modifications of polymer brushes. The instructor explains the controlled surface-initiated polymerization techniques and various strategies like ST-NMP and S-RAFT. The lecture also explores the use of polymer brushes in protein microarrays, adhesion of endothelial cells, and ion sensors, showcasing case studies and experimental setups.