PROBING COLLECTIVE MOTIONS OF TERMINALLY ANCHORED POLYMERS

Polymer chains attached by one end to an impenetrable surface at high coverage exemplify a tethered layer of mesoscopic dimensions. At equil ibrium, thermal fluctuations of the segment density profile of the bru shlike layer reflect the tethered chain dynamics; the probing of these fluctuations by evanescent-wave dynamic light scattering is reported. By utilizing a set of terminally attached layers with thicknesses (L( 0)) from 45 to 130 nanometers, it was found that there is a preferred wavelength of order L(0) of these fluctuations with a concurrent slowi ng down of their thermal decay rate. This technique could open the rou te for the investigation of the largely unexplored area of polymer sur face dynamics.