Self-Assembly Behavior of Amphiphilic Poly(2-ethyl-2-oxazoline)-<i>b</i>-poly(2-isostearyl-2-oxazoline) Block Copolymers
James Lefley, Roberto Terracciano, Zivani Varanaraja, James Beament, C. Remzi Becer
Abstract
High Resolution Image Download MS PowerPoint Slide By utilizing a unique hydrophobic 2-oxazoline monomer, we report the facile and efficient synthesis of a novel poly(2-ethyl-2-oxazoline)- block -poly(2-isostearyl-2-oxazoline) copolymer library via cationic ring-opening polymerization. Varying the hydrophilic–hydrophobic block ratios of the copolymers afforded good control over thermal properties such as the glass transition temperature, leading to an increase from 0 to 60 °C as the volume fraction of the 2-ethyl-2-oxazoline block increased. A solvent-free self-assembly method was employed to study the self-assembly behavior of the copolymer library. Thus, using thin film hydration, a wide range of self-assembled structures were obtained in aqueous solution. Structures such as micelles, short and long worms, and unilamellar and multilamellar vesicles were observed and characterized via dynamic light scattering and electron microscopy analysis. All structures exhibited excellent stability in solution at ambient temperatures over a 2 month period and showed thermoresponsive behavior.