CONFORMATION OF NEUTRAL POLYAMPHOLYTE CHAINS IN SALT-SOLUTIONS - A LIGHT-SCATTERING STUDY

The salt aqueous solution properties of a low charge density polyampho lyte terpolymer with a balanced stoichiometry of charges were investig ated by static and dynamic light scattering. At high ionic strength, t he sample is entirely soluble and the chains exhibit an excluded volum e conformation. When the salt content is lowered, part of the sample p recipitates, leaving in the supernatant highly swollen chains. The res ults are interpreted by assuming that, due to different reactivity rat ios of the monomers, there is a distribution of the net charges among the polymer chains. By varying the salt content, one performs a fracti onation of the polyampholyte chains according to their net charge.