Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

Abstract

A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core-shell micelles composed of linear diblock copolymers poly(ethylene glycol)-<i>b</i>-poly(caprolactone) (PEG-<i>b</i>-PCL), poly(ethylene oxide)-<i>b</i>-poly(lactic acid) (PEG-<i>b</i>-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-<i>g</i>-PEG/PLA) were characterized by dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core-shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.