COATING OF A HYDROPHOBIC POLYMER SUBSTRATE WITH A NONSTOICHIOMETRIC POLYELECTROLYTE COMPLEX

摘要

A method of coating the surface of a substrate, such as a film or a fibrous web, which is composed of a hydrophobic polymer. The method involves providing a solution of a first polyelectrolyte having ionizable groups and a solution o f a second polyelectrolyte having ionizable groups. The two solutions then are mixed under conditions adapted to result in the formation of a nonstoichiometric polyelectrolyte complex. Finally, the surface of the hydrophobic polymer substrate is contacted with a solution of the complex under conditions sufficient to result in the coating of the surface of the substrate with the complex. The ionizable groups of the secon d polyelectrolyte have a latent charge opposite the latent charge of the ionizable groups of the first polyelectrolyte. Moreover, the amounts of the first and second polyelectrolytes are selected to give a ratio of the number of ionizable groups in the first polyelectrolyte to the number of ionizable groups in the second polyelectrolyte of at least about 2, and the molecular weight of the first polyelectrolyte is a t least about 40,000 daltons and at least about 2 times the molecular weight of the second polyelectrolyte.