Towards controlling the morphology of cobalt loaded nanocomposites in polyol process with polyethylene glycol

Abstract

The polyol process is one of the simple, efficient and productive methods for the synthesis of metal loaded polymer composites. Functional properties of metal-polymer nanocomposites are determined by chemical composition, size and morphology of their particles. Finding effective ways to control the nanoparticle's properties during the polyol process is a crucial task. The effect of molar ratio Mⁿ⁺/OH_PEG on the formation of cobalt loaded metal-polymer nanocomposites during a one-pot two-component polyol process by polyethylene glycol with M_r = 4000 g·mol^–1 (PEG) was studied. The PEG-based polyol process and the formation of cobalt nanophase were studied at molar ratios ν_Co2+/ν_OH(PEG) = 1:1, 1:10, 1:100 and 1:500 using UV-Vis, diffuse reflectance IR and ATR FT-IR spectroscopy, nanoparticle tracking analysis (NTA), dynamic light scattering (DLS). It was found that PEG can act as a reducing agent and stabilizing matrix for the cobalt nanophase at a ratio higher than Mⁿ⁺/OH_PEG= 1:10. The composition and morphology of Co/PEG nanocomposites were determined by XRD and TEM methods. Two types of spheroid particles with average diameters of 88±55 nm / 8±4 nm and 12±3 nm / 3±1 nm, respectively, represent Co/PEG nanocomposites 1:500 and 1:100. Scaly structures with a diameter of 15±5 nm are formed at a molar ratio of ν_Co2+/ν_OH(PEG) = 1:10. An increase in the Co²⁺ content in the PEG-based polyol process leads to the immobilized cobalt nanophase Co₃O₄ (1:500), Co⁰/CoO (1:100), CoO (1:10) in PEG. Co/PEG nanocomposites are hemocompatible. The HC₅₀value depends on the composition and morphology of the nanoparticles.