Structure and properties of polymer core-shell systems: Helium ion microscopy and electrical conductivity studies

Abstract

Peculiarities of the structural organization and electrical properties of two core-shell polymer systems under different fabrication protocols have been studied with a combination of helium ion microscopy (HIM) and current-voltage characterization. The systems under study included a submicrometer core of a ferroelectric polymer polyvinylidene fluoride and a shell of intrinsically conducting or semiconducting polymer polyaniline (PANI) or poly(3-methylthiophene) (P3MT). Application of HIM allowed identification of the polymer components, visualization of the electrically conductive percolation network of PANI or P3MT, and its variation due to thermal annealing and/or interaction with the environment. HIM is proved to be a powerful tool for characterization of not only the morphology but also of the charge distribution and conductivity properties on the nanoscale. The specific contrast formation in HIM imaging is due to differences in local electrical conductivity of the components. The authors have demonstrated that the polymer core-shell systems under study can serve as a universal platform for development of nanostructured multifunctional materials. Specifically, it is shown that they can be used for preparation of conducting and semiconducting polymer films or layers having promising nonlinear electrical and sensor properties.