MONTE-CARLO SIMULATIONS OF POLYELECTROLYTES AT CHARGED HARD-SPHERES WITH DIFFERENT NUMBERS OF POLYELECTROLYTE CHAINS

The complexation of a charged hard sphere (macroion) with short and op positely charged polyelectrolytes was studied by the use of a simple m odel system. Structural data of the macroion-polyelectrolyte complex a nd the surrounding solution were obtained by the use of Monte Carlo si mulation technique. The number of polyelectrolyte chains as well as th e linear charge density and the flexibility of the polyelectrolyte wer e varied, whereas the properties of the macroion were held constant. I n all cases, the macroion and a polyelectrolyte carried an equal numbe r of elementary charges. The simulations showed that for flexible and highly charged polyelectrolytes, a tight complex containing the macroi on and one polyelectrolyte was formed independent of the number of pol yelectrolytes present. However, for flexible but lower charged polyele ctrolytes, a looser macroion-polyelectrolyte complex was established, and a complex involving two polyelectrolytes occurred when two or more polyelectrolytes were available. Finally, for the most rigid polyelec trolyte no complex was formed at all. Generally, an intramolecular con traction of the polyelectrolyte occurred upon complexation with the ma croion. (C) 1998 Americnn Institute of Physics.