X-ray photon correlation spectroscopy of silica particles grafted with polymer brush in polystyrene matrix

X-ray photon correlation spectroscopy system was setup at SPring-8, BL19LXU, and the partial coherence scattering data from the silica particles grafted with polymer brush in polystyrene matrix were measured. Firstly, the static speckle patterns were checked. Below the glass transition temperature of polystyrene (T_g), speckles were clearly observed, on the other hand, above T_g, the scattering patterns became smooth and speckles were hardly observed. These variances of the speckle patterns result from the particle motion. Secondly, from the time variance of the speckle data, time autocorrelation functions g₂(q,t) are calculated. While the flat behaviour of g₂(q,t) without relaxation were observed below T _g, the relaxation behavior with relaxation time∼10 ⁰-10¹ were observed above T_g