| dc.description.abstract | In this study, association properties of aqueous solutions of anionic thermo-responsive hydrophobically end-capped amphiphilic triblock terpolymer n-octadecyl-poly(ethylene glycol)-poly(N-isopropyl acrylamide)-block-poly(2-acrylamido- 2-methyl-1-propanesulfonic sodium), abbreviated as C18-PEG10-b-PNIPAAm54-b-PAMPS10, have been studied by means of zeta potential measurements, turbidimetry, dynamic light scattering (DLS), densitometry and small angle light scattering (SANS) at various temperatures, polymer concentrations, and salinities. This polymer exhibits lower critical solution temperature (LCST) owing to its PNIPAAm block. Increasing the ionic strength of the aqueous solutions leads to a decrease in the cloud point (CP) of the solutions which is an indication of enhanced aggregation due to the screening of Coulomb repulsions. The dynamic light scattering (DLS) data gives a detailed information about the interactions between intra-chain and inter-chain associations. The zeta-potential is augmented through temperatures due to increase in charge density. The effect of ionic strength induced by adding different amounts of NaCl on solutions of the applied triblock terpolymer has been examined by means of turbidimetry, dynamic light scattering , densitometry and small angle neutron scattering (SANS). By increasing the amount of added salt, the electrostatic interactions are screened out and increasing the temperature promotes the formation of large aggregates. It has been demonstrated by turbidimetry experiments that CP is depressed when the ionic strength is increased. The results from DLS and SANS also confirm that higher salt concentration result in the formation of large aggregates at elevated temperatures. | eng |