Surface Mechanical Behavior of Water-Spread PS–PEG Cylindrical Micelles at the Air-Water Interface

Our lab has been studying the air-water interfacial properties of PS-PEG micelles, exploring their potential for treating respiratory distress syndrome (RDS). Initially, our research focused on spherical micelles formed by PS-PEG block copolymers. This presentation presents our latest findings regarding the behavior of cylindrical micelles at the air-water interface. We prepared kinetically-frozen PS-PEG cylindrical micelles via equilibration-nanoprecipitation. Similar to spherical micelles, cylindrical ones demonstrated the ability to generate high surface pressure (>70 mN/m) upon compression, a critical factor for RDS therapy. However, cylindrical micelles exhibited a distinct monolayer-to-bilayer transition, resulting in a secondary plateau in their surface pressure-area isotherm, preceding ultimate collapse during compression—a phenomenon absent in spherical micelles. Additionally, the population of cylindrical micelles influenced increased hysteresis on the surface pressure-area isotherm during compression and expansion cycles. This work demonstrates the potential to optimize therapeutic outcomes by fine-tuning the surface mechanics of PS-PEG micelles through tailored micelle shapes.