SCATTERING FUNCTIONS OF SEMIFLEXIBLE POLYMERS WITH AND WITHOUT EXCLUDED-VOLUME EFFECTS

Off-lattice Monte Carlo simulations on semiflexible polymer chains wit h and without excluded volume interactions have been performed. The mo del used in the simulations is a discrete representation of the worm-l ike chain model of Kratky and Pored applied in the pseudocontinuous li mit. The ratio between the cross-section radius R of the chain and the statistical segment length b was chosen to be R/b = 0.1 which corresp onds to the value found for polymer-like micelles. The ratio R/b is eq uivalent to a reduced binary cluster integral of B = 0.30, which is in accordance with the value for polystyrene in a good solvent. The scat tering functions of the semiflexible chains have been determined with a precision of 1-2% for L/b = 0.3-640, where L is the contour length o f the chain. Numerical approximations to these functions have been det ermined which interpolate between the simulated functions, and these c an be used in the analysis of experimental scattering data. The approx imations have been used in least-squares fitting of experimental small -angle neutron scattering data from polystyrene in a good solvent.