A study of mass transport of linear polystyrene in polyethyl methacrylate gel by dynamic light scattering

Abstract

Mass [i.e., linear polystyrene (PS) probe] transports in polyethyl methacrylate (PEMA) gels with ethylene dimethacrylate (EDMA) as crosslinker were studied by dynamic light scattering (DLS). For PEMA gels in toluene, we have established that it is a very well matched system, so that it is very convenient to study the mass transport of the PS macromolecule in such a system. Experiments show that the obstruction effects of PEMA gels for the mass transport of PS are obvious. Reasonably, the lower the gel obstruction for mass transport, the higher the diffusion coefficient D t of PS in gel. Moreover, the larger the molecular weight of PS, the greater the obstruction effect of the gel. Furthermore, we traced quantitatively the evolution of D t of PS during the crosslinking copolymerization of PEMA. The results show that, after the reaction, the obstacle for mass transport in the gel develops gradually.

Influence of Cross-Linking on Probe Dynamics in Semidilute Polystyrene Systems

“…Several investigations on the dynamics of polymers in melts as well as in semidilute and concentrated solutions and in gels agree, at least in part, with the scaling laws of reptation. Different techniques have been applied, such as forced Rayleigh scattering (FRS), ,,− dynamic light scattering (DLS), ,− pulsed field gradient NMR, − fluorescence recovery after photobleaching (FRAP), ,− fluorescence correlation spectroscopy (FCS), − and single molecule tracking . In particular, the M −2 prediction could be confirmed, e.g., by studies of Wesson et al, Wheeler et al, and Nemoto et al on the dynamics of polystyrenes enclosed in polymer solutions at different concentrations. ,,, Inspection of the concentration dependence of the diffusion coefficient seems to be more difficult than studying the molecular weight dependence.…”