FEATURES OF GELATION AND AGGREGATION IN AQUEOUS SOLUTIONS OF HYDROXYPROPYL CELLULOSE WITH NaCl, NaI, AND AgNO3

Using the turbidimetric method and the method of static light scattering, the features of gelation and aggregation in 2 wt% and 0.2 wt% aqueous solutions of hydroxypropyl cellulose (HPC) with NaCl, NaI, and AgNO3 salts have been studied. It is found that the introduction of these salts into the 2% solution reduces the coefficient of surface tension at the interface between the sol and gel phases, decreases the lower critical solution temperature (LCST), and slows down the sol-gel transition rate. From the data on static light scattering, it follows that in the dilute (1 :10) aqueous solutions of HPC at temperatures above the LCST and in the presence of salts, there arise supramolecular associates (clusters) that are several times larger than the wavelength of visible light. The precipitation of polymer is observed. It is shown that the intensity of reflected light can be described as a function of the cluster size in the framework of the Mie scattering theory. It is found that the density of polymer aggregates in the AgNO3 solution was the highest among the studied specimens, which can be explained by the reduction of silver nitrate to metal. The sedimentation of HPC clusters containing silver nanoparticles can be used for creating composite polymer films with the bactericidal and fungicidal activities.