EFFECT OF SOLVENT QUALITY ON THE CONFORMATION AND RELAXATION OF POLYMERS VIA DISSIPATIVE PARTICLE DYNAMICS

Dissipative particle dynamics (DPD), a new simulation technique approp riate at mesoscopic length scales, has been applied to a dilute soluti on of polymer in solvents of varying quality, Unlike earlier simulatio ns, the solvent is represented in the form mobile particulate packets, so that potential interferences of solvent flow about neighboring bea ds of the polymer are explicitly included. We establish that the mecha nism used to vary the solvent quality produces a collapse transition, as judged both by static conformational and by dynamical criteria. The scaling of the polymer radius of gyration and of its longest dynamica l relaxation time are in good agreement with accepted theory. The cond ition for transition from good to poor solvent is consistently predict ed by several static and dynamical measures. Though the model that und erlies DPD is not atomically detailed, the results presented strongly suggest that both excluded volume and hydrodynamic interaction must pr esent. (C) 1997 American Institute of Physics.