Nanoparticle debonding strength: A comprehensive study on interfacial effects

The most appealing feature of nanofilled polymers is the perspective of obtaining surprisingly high mechanical properties at low nanofiller volume fractions. The knowledge of nanostructure-property relationships is however essential for the design of these materials. In the present work, a model for the critical hydrostatic tension related to nanoparticle debonding is presented. The model accounts for some important issues inherently related to the nanoscale with particular reference to surface elastic stresses on the nanoparticle periphery and the emergence of a zone of altered chemistry surrounding the nanoparticle. The analytical solution suggests that the range of nanoparticle radii where interfacial effects do affect the solution is limited to the nanometer scale. In more details, considering the interphase and surface elastic properties used in the analysis, it has been found that for stiff particles with radius between 10 nm and 100 nm (silica, alumina and other metal oxide nanoparticles) the prominent role is played by the interphase elastic properties. Surface elastic constants were found to have, instead, only a negligible effect