ELECTROSTATIC PERSISTENCE LENGTH OF NAPSS POLYELECTROLYTES DETERMINEDBY A ZERO AVERAGE CONTRAST SANS TECHNIQUE

The electrostatic persistence lengths b(e) of NaPSS polyions have been measured as a function of ionic strength I in the solutions using a s mall-angle neuron scattering (SANS) technique combined with a zero ave rage contrast (ZAG) method. This ZAC method provides the optical theta condition distinguishing the intermolecular scattering functions S-2( q), and thereby the scattering functions of a single chain S-1(q) free from the intermolecular interferences were obtained. The resulting b( e) values which were derived by the analysis of S-1(q) are proportiona l to I-1/2. This work confirms and extends an earlier SANS study where the contrast-match was used. (C) 1997 Elsevier Science Ltd.