Label-free measurement of core-shell Pluronic F127 Micelle nanostructure determined using in-situ Resonant Soft x-ray Scattering*

Micelles are key to many applications such as drug delivery, and their size, shape and internal molecular conformation are of critical importance to their performance. By having both hydrophobic and hydrophilic monomer groups, polymers like Pluronic F127 self-assymble into spherical core-shell structures called Micelles. However, confirming the structural parameters, in particular conformation, is difficult if not impossible to date. Here we demonstrate a novel technique capable of such measurements based on Resonant Soft X-ray Scattering (RSoXS), which is uniquely sensitive to bond orientation and capable of probing organic materials using their intrinsic chemical structure for contrast manipulation rather than laborious and potentially disruptive isotopic labeling that is required in techniques such as neutron scattering. Like electron microscopy, RSoXS requires a high vacuum environment. By adapting a Poseidon Protochips TEM holder for use at BL11.0.1.2 of the Advance Light Source, we show that RSoXS can now be performed in in-situ/operando environments, allowing sample structure and interactions to be measured in the same conditions/environment as the intended application.