Influence of mixed CTABr–C16E20 nanoparticles on relative counterion binding constants in aqueous solutions of inert salts (2-NaOC6H4CO2Na and NaBr): kinetic and rheometric study. Issue 98 (6th October 2016)

• Record Type: Journal Article
• Authors: Fagge, Ibrahim I.; Khalid, Khalisanni; Noh, M. Azri M.; Yusof, Nor Saadah M.; Zain, Sharifuddin Md; Khan, M. Niyaz
• Is Part Of: RSC advances. Volume 6:Issue 98(2016)
• Page Start: 95504
• Page End: 95511
• Publication Date: 2016-10-06
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra19106a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A semi-empirical kinetic technique has been used to obtain the ratios of pure CTABr (cationic nanoparticle) and mixed CTABr–C16 E20 (cationic–nonionic nanoparticle) micellar binding constants of counterions X and Br, K X / K Br (= K BrX or R BrX) for X = salicylate ion. Abstract : A semi-empirical kinetic technique has been used to obtain the ratios of pure CTABr (cationic nanoparticle) and mixed CTABr–C16 E20 (cationic–nonionic nanoparticle) micellar binding constants of counterions X and Br, K X / K Br (= K BrX or R BrX) for X = salicylate ion. The values of K BrX or R BrX for the salicylate ion remain typically independent of the concentration of pure micelles, [CTABr]T (0.006–0.015 M). These values are also independent of mixed [CTABr]T –[C16 E20 ]T micelles under similar conditions. The presence of C16 E20 decreases the average values of K BrX or R BrX from 42 to 16 for salicylate ions. Increase in concentration of cationic and cationic–nonionic nanoparticles at a fixed amount of CTABr reveals the monotonic increase in the value of k obs, which was explained using the PPM model together with an empirical equation. Rheological characteristics of 0.015 M CTABr solutions in the presence of disodium salicylate indirectly show the presence of branched elongated nanoparticles at 25 °C and 35 °C and [C16 E20 ]T = 0. Contrarily, such findings reveal the existence of spherical micelles at 25 °C and 35 °C in the presence of ≥0.006 M [C16 E20 ]. The values of K BrX or R BrX and rheological observations clearly demonstrate that 0.015 M CTABr/M2 X/H2 O (M2 X = disodium salicylate, 2-NaOC6 H4 CO2 Na) solutions contain wormlike and spherical micelles when K BrX or R BrX values are ≈42 and 16, respectively.