Effect of SiO₂ Nanoparticles on the Conformations of Poly(ethylene oxide) Polymer Chains

The behavior of polymers restricted in space or close to surfaces/interfaces can be very different from that in the bulk. In this work, the chain conformations in poly(ethylene oxide) / silica nanoparticles, PEO / SiO₂, nanohybrids has been investigated through a combined approach that involves Fourier Transform Infrared spectroscopy (ATR-FTIR) measurements and molecular dynamics (MD) simulations. Systems with different polymer molecular weights, nanoparticle radii and concentrations have been employed to investigate the effect of the confinement on polymer conformations. Qualitatively similar behavior between experimental and simulation results is observed since in both cases an increase of gauche population for the OCCO angle is attained, in comparison to the respective of the bulk; this increase becomes larger as the degree of confinement becomes higher. On the contrary, the conformations of the C-O bond (COCC angle) seem to remain unaffected by the confinement, at least in the range of degrees of confinement covered computationally. This research has been co-financed by the General Secretariat for Research and Technology (Action KRIPIS, project AENAO, MIS: 5002556).