DILUTE NONINTERACTING POLYMER IN A LAMELLAR SYSTEM

It has been found that by introducing a dilute solution of a neutral, flexible polymer (polyacrylamide) in brine as the solvent in a mixture of surfactant (cetylpyridinium chloride) and cosurfactant (hexanol), the system experiences a strong decrease of the interlamellar spacing of the L(alpha) phase, at practically constant bilayer thickness. We p resent here a model of the ''flocculation'' type which attributes this depletion to the osmotic pressure gradient introduced around each pol ymer coil, which causes the membranes to be drawn together, assuming n o other interaction between the polymer and the membrane.