Publication Date:
2018
Description:
〈p〉Publication date: 5 January 2019〈/p〉
〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉
〈p〉Author(s): Nobuo Uehara〈/p〉
〈h5〉Abstract〈/h5〉
〈div〉〈p〉Cationic and anionic thermoresponsive polymers were synthesized and the formation of their hydrophobic aggregates with ionic surfactants was studied at extremely low polymer concentrations. Alongside the hydrophobic interactions, electrostatic interactions between the ionic groups of the polymers and surfactants played a major role in the formation of the hydrophobic aggregates. In the absence of an ionic surfactant, extremely dilute (i.e., 0.01 wt %) polymer solutions did not become turbid, even when they were heated above the phase-transition temperature. However, above the phase-transition temperature, the polymer solutions became turbid upon the addition of a specific concentration of an ionic surfactant with the opposite charge. In contrast, no increase in the turbidity was observed when an ionic surfactant with the same charge was added to the solution, regardless of the concentration of the ionic surfactant. Even below the phase-transition temperature, the application of a fluorescent probe that responded to the hydrophobicity of its environment revealed that the ionic thermoresponsive polymers formed a hydrophobic environment with oppositely charged surfactants owing to the electrostatic and hydrophobic interactions, even though hydrophobic precipitates were not observed. Thus, the electrostatic interactions between polymers and surfactants played crucial roles in the formation of hydrophobic aggregates under extremely low concentration of the polymers as well as the hydrophobic interactions did.〈/p〉〈/div〉
〈h5〉Graphical abstract〈/h5〉
〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313104-ga1.jpg" width="273" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉
Print ISSN:
0927-7757
Electronic ISSN:
1873-4359
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
