Mechanical and Structural Properties of BaCrO4 Nanorod Films under Confinement and Shear

Using an X‐ray surface forces apparatus (X‐SFA) we have investigated the effects of normal load (stress) and shear on the ordering and tribological properties of 10 nm × 30 nm surfactant‐coated BaCrO4 nanorods in isooctane, confined within submicrometer films. The film structure and corresponding friction forces were monitored as a function of time and shearing distance at different gap sizes and loads. The X‐ray diffraction patterns indicate a cubic phase of nanorods coexisting with a surfactant phase that depends on the load, film thickness, shear rate, and shearing time. Atomic force microscopy and birefringence measurements performed on each surface after a shearing experiment showed ordered domains of nanorods over length scales of several tens of micrometers. The effects of normal load (stress) and shear on the ordering and tribological properties of surfactant‐coated BaCrO4 nanorods confined within submicrometer films have been investigated. X‐ray diffraction patterns indicate a cubic phase of nanorods coexisting with a surfactant phase (see Figure) whose relative amounts depend on the load, the film thickness, shear rate, and the shearing parameters.