Critical particle size for interfacial debonding in polymer/nanoparticle composites

Interfacial debonding in polymer/nanoparticle composites under uniaxial loading is studied using meso-mechanics By means of Eshelby's equivalent inclusion method, the step differences of stress and strain Just before and after the debonding for a single ellipsoidal particle embedded in an infinite matrix are obtained The debondmg criterion is derived from an energetic analysis Then, the relationships between the interfacial adhesion strength and the work of adhesion of the components, the shape and size of the particle, and the mechanical properties of both constituents are discussed. The critical particle size, defined as that size below which no interface debondmg can occur, is calculated for two special cases. spherical and penny-shape particles It is shown that this critical size depends on the absolute value of the work of adhesion In the adhesion range of 0 01-0 40 J/m(2), the critical radius of a sphere particle varies from tens to several hundreds of nanometers However, for a penny-shape particle with loading parallel to its faces, the critical particle size is at least several micrometers for an aspect ratio of 100 (C) 2010 Elsevier Ltd All rights reserved