Titre : AFM-IR Spectroscopy and Imaging of Polymer Nanofibers and Thin Films at the Nanoscale.
Endroit : Pavillon Roger-Gaudry, salle G-715 à 11 h
Hôte : Professeur Christian Pellerin
La conférence sera prononcée (en anglais) par le professeur John Rabolt, du département des sciences des matériaux et de génie de l'University of Delaware.
Résumé : The combination of atomic force microscopy (AFM) and infrared (IR) spectroscopy is an extremely powerful tool that can provide topographic information that can be correlated with chemical, conformational and molecular orientation information at a spatial resolution of 50-100 nm. Using an AFM-IR instrument, we have explored the correlation between structure, processing and chain orientation/crystallinity in biodegradable and biocompatible poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (PHBHx) electrospun nanofibers and thin films and tested the hypothesis that different processing protocols can alter the concentration of the stable α-crystalline form and the metastable β-crystalline form. The ability to obtain IR spectra at high spatial resolutions has allowed us to probe, for example, crystalline populations as a function of nanofiber diameter and as a function of location within the fiber and we have observed, for the first time, the existence of a core-shell structure in a single electrospun nanofiber. In addition, the spectroscopic imaging capability of the AFM-IR instrument has been utilized to create a map of α and β crystalline content as a function of location within the nanofiber and this clearly verifies the existence of a core-shell structure.
