Systematic analysis and nanoscale chemical imaging of polymers using photothermal-induced resonance (AFM-IR) infrared spectroscopy

In this work, a reliable and time-saving protocol for the measurement of polymers using photothermal-induced resonance (AFM-IR) at the nanoscale was developed and applied to 4 industrially relevant polymers: a polypropylene-based reactor thermoplastic polyolefin (rTPO), linear low density polyethylene (LLDPE) for molding and two recycled post-consumer polypropylene/polyethylene blends. In addition to the morphology obtained through AFM, we were able to identify and image the major components of each polymer, including the mineral fillers (talc and calcium carbonate) present in each blend using nanoscale spatial resolution infrared imaging. The protocol developed allows the quick analysis and identification at the nanoscale of the major components of a blend without having previous knowledge of the sample composition, a major advantage when compared to other traditionally used imaging techniques such as TEM and SEM.