Multimodal STEM Investigation of Polymer Damage Processes Induced by Electron Beam Irradiation

Abstract

Abstract Self-assembled polymer nanostructures are useful for many applications, including biomedicine, energy, and sensing, often presenting a more stable and customizable alternative for drug delivery than lipid-based assemblies, like liposomes. Polyethylene glycol-b-poly(propylene sulfide) (PEG-b-PPS) nanostructures are an example of a cutting-edge self-assembled polymer system. Here, to better understand the impact of electron irradiation on the molecular and macroscale structure, we utilize analytical scanning transmission electron microscopy. Through electron energy-loss spectroscopy (EELS), we access information regarding the degradation of PEG-b-PPS self-assembled polymers under the electron beam. By coupling the spatial and temporal resolution afforded by EELS, we describe the movement of elements in the polymer system during radiolysis and propose a mechanism for sample degradation. We believe this work will serve as a blueprint to determine the effects of electron irradiation on polymer architectures via spectroscopy.