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 fibrousweb,which is composed of a hydrophobic polymer. The method involves providing asolution of a first polyelectrolyte having ionizable groups and a solution ofa secondpolyelectrolyte having ionizable groups. The two solutions then are mixedunderconditions adapted to result in the formation of a nonstoichiometricpolyelectrolytecomplex. Finally, the surface of the hydrophobic polymer substrate iscontacted with asolution of the complex under conditions sufficient to result in the coatingof thesurface of the substrate with the complex. The ionizable groups of the secondpolyelectrolyte have a latent charge opposite the latent charge of theionizable groupsof the first polyelectrolyte. Moreover, the amounts of the first and secondpolyelectrolytes are selected to give a ratio of the number of ionizablegroups in thefirst polyelectrolyte to the number of ionizable groups in the secondpolyelectrolyte ofat least about 2, and the molecular weight of the first polyelectrolyte is atleast about40,000 daltons and at least about 2 times the molecular weight of the secondpolyelectrolyte.