Label-free characterization of aqueous micelle nanostructure, chemistry, and dynamics via in-situ RSoXS*

Micelles are key to nanocarrier applications from drug delivery to environmental remediation. Their structure and dyanmics are of critical importance to their properties and functions but are difficult to measure. Here we demonstrate a novel technique capable of such measurements based on resonant soft X-ray scattering (RSoXS), which uniquely probes organic materials using their intrinsic chemical bonds rather than laborious and disruptive labeling. Our customized microfluidic cell enables RSoXS to be performed in liquid environments, allowing structure and dynamics to be measured in-situ. We first apply the technique to a model smart medicine platform, Pluronic F127. Resonant contrast tuning allows the internal structure and chemical composition to be measured quantitatively without labeling. We further investigate a novel amphiphilic statistical copolymer designed for oil spill remediation. Dynamic dual flow reveals an unexpected concentration dependence of the corona, which was not resolved with traditional visible light scattering. We further show that despite aggregation, the unimeric bridged-core structure is retained at all concentrations, crucial for its application.