Correlative Analysis of Specific Compatibilization in Composites by Coupling in situ X-Ray Scattering and Mechanical Tensile Testing

Abstract

In this study, a bio-inspired hybrid material is investigated by in situ X-ray scattering experiments in combination with mechanical tensile testing. The material is composed of nanometer-sized spherical magnesium fluoride particles which are linked via material-specific peptide poly(ethylene glycol)-PEG conjugates to a semi-crystalline poly(ethylene oxide) PEO matrix. Mechanically relevant changes in crystal size and orientation in the PEO matrix are followed by wide angle X-ray scattering during the application of tensile stress. The amorphous phase of PEO is stabilized by the surfaceengineered MgF 2 nanoparticles, leading to increased Young's modulus and tensile strength. Furthermore, small angle X-ray scattering experiments allowed the identification of a layer on the MgF 2 particle surfaces, which increases in thickness with the conjugate amount and leads to suppression of the agglomeration of MgF 2 nanoparticles. In conclusion, the use of selected peptide-PEG conjugates tailored to link MgF 2 particles to a PEO matrix successfully mimics the biological principle of interface polymers and suggests new directions for material fabrication for bio-applications.