Thermal gradient effect on the dynamical behavior of nanoparticles observed using X-ray photon correlation spectroscopy

The effects of a thermal gradient on the dynamical behavior of nanoparticles dispersed in a polymer matrix were studied using X-ray photon correlation spectroscopy. Polystyrene (PS)-grafted silica nanoparticles (SiNPs-PS), which are nanoparticles dispersed in a PS matrix controlled at temperatures above the glass transition temperature, were used in this study. Anisotropic motions of the SiNPs-PS were observed when the sample was kept in a conventional capillary tube, whereas isotropic motion was observed when the sample was kept in a newly designed cell with a low thermal flow, demonstrating the importance of the thermal gradient on the dynamical behavior of the SiNPs-PS.