| Abstract: | Thermal fluctuations of the segment density profile of a polymer brush were probed by dynamic light scattering in the evanescent wave configuration; the time correlation functions of concentration fluctuations with wavevector q were measured. It is found that there is a preferred wavelength of the order of the brush thickness, L0, of these fluctuations with a concurrent slowing down of their thermal decay rate. A theory is presented for the small-amplitude deformation of the free surface of a parabolic brush in solution; a maximum in the respective structure factor of the concentration fluctuations is predicted at q* L0 ∼ O(1), in agreement with the experiment. |
