Characterization of the adhesion between nanoparticles and polymer matrix by atomic force microscopy

Mechanical properties of a nano-composite consisting of nano-particles (e.g. carbon nanotubes, graphene, or nanoplatelets) embedded in a polymer matrix can be enhanced by manipulating the interfacial interactions between the nanoparticle and the polymer matrix. Polymer-nanoparticle adhesion allows the transfer of stress to the reinforcing particles which results in an increase in material strength. On the other hand, polymer-nanoparticle bonds can absorb energy by breaking and forming microvoids; the formation of microvoids during deformation increases toughness (impact strength). Hence, an investigation of the interfacial bonding strength and related interaction characteristics using Atomic force microscopy (AFM) is conducted. Two techniques (force/distance curve and extend distance curve) are proposed, and their advantages and limitations are addressed in this paper.