(18a) Mechanical Properties of Nanoparticle Chain Aggregates by Combined Afm and Sem: Isolated Aggregates and Networks

Nanoparticle chain aggregates (NCA) are frequently generated in high temperature processes. Examples include industrial and laboratory aerosol reactors and the combustion of carbonaceous fuels. They are branched structures composed of primary particles with diameters ranging from 1 to 50 nm. The mechanical properties of NCA are important in the manufacture of composite materials such as reinforced rubber, and the fabrication of sensor films, nanoparticle catalyst films and planarization agents. NCA also play a major role in air pollution.

Mechanical properties of NCA including tensile strength and Young's modulus were measured using an instrument incorporating an AFM tip under SEM imaging. The AFM nanomanipulator allows force measurements in the range of nanonewtons while simultaneously the SEM permits visual observation of the strain and the diameter of the neck at which breaking occurred. This permitted calculation of tensile strength, Young's modulus and contact force of the NCA. The reversibility of NCA networks, which has not been described before, may provide insight to the mechanism of filler reinforcement in rubber and other elastomers and the potential application of NCA networks to the fabrication of deformable electronic surfaces.