Conductive poly(pyrrole-co-(1-(2-carboxyethyl)pyrrole)) core-shell particles: Synthesis, characterization, and optimization

Abstract

Abstract Functional conductive polymers such as poly(pyrrole-co-(1-(2-carboxyethyl)pyrrole)) (P(Py-PyCOOH)) copolymer has raised significant research interests in biomedical field for their electrical conductivity, biocompatibility, and functionality that facilitates further biological modifications. However, most P(Py-PyCOOH) polymers are synthesized through electropolymerization with small sample size and low productivity. In this work, the core-shell P(Py-PyCOOH) particles were synthesized through a simple one step emulsion polymerization. Experimental parameters including the ratio of water/oil, feeding of FeCl3 and functional monomers, as well as reaction time were evaluated to define the balanced optimal conditions. The obtained P(Py-PyCOOH) particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and total elements analysis. The particles present a core-shell structure comprising the pyrrole (Py) dominated P(Py-PyCOOH) copolymer as the core and PPyCOOH homopolymer as the shell. Given the composition of the shell, the quantity of carboxyl groups on particle surface already reached maximum; further polymerization of excessive functional monomers would not increase any surface functionality but decrease conductivity of the particles. To conclude, the core-shell P(Py-PyCOOH) particles possess a good conductivity (>10−3 S cm−1), maximized surface functionality, large surface area, excellent dispersibility in water, and high overall yield. Such conductive particles can be good candidate for sensing and biomedical applications.