A 2D-Raman correlation spectroscopy analysis of the polymeric nanocomposites with magnetic nanoparticles

Abstract

Magnetic iron oxide nanoparticles (MNPs) possess peculiar physical properties which make them possible to use in a variety of applications such as magnetic resonance imaging (MRI), drug delivery, hyperthermia treatment, as well as bone tissue engineering. The MNPs have been already proven to enhance and accelerate the proliferation of osteoblast cells and new extracellular matrix (ECM) secretion. In the presented study MNPs, that varied in concentration of oleic acid (OA) used during their modification (that resulted in MNPs’ coating and surface functionalization by OA), were introduced into a polymeric matrix of PCL. The impact of MNPs on membranes’ structure was investigated, and the difference of MNPs production was also taken into consideration. The study included classical materials engineering techniques, such as water contact angle measurements, surface energy testing, and also spectroscopic methods: Raman micro-spectroscopy and 2D correlation Raman spectroscopy. The results show that polymeric ν(CO) vibration and δ(CH2) vibration of OA are structurally significant for magnetic membranes. A clear insight into the interfacial relations of both chemically similar phases (polymer matrix and MNPs’ coating) was obtained and it was revealed that CH2 vibrations of OA precedes and induces changes occurring in CH2 of PCL. Also, the interactions of polymer CO groups with MNPs was observed, but it is a need to be noted that 2D-COS signals coming from MNPs’ coating are more characteristic.