The development of low energy, magnetically driven separations techniques offer a means to address the growing energy demands for chemical and biological separations. In order for magnetically-driven separations to be realized, additional research must be performed to determine fundamental structure-property relationships for magnetic surfactants. Unlike previous reports of magnetic colloids utilizing paramagnetic nanoparticles, this research focuses on amphiphiles with the paramagnetic moiety either as the counterion (Type 1) or chelated (Type 2) to the surfactant. We have synthesized ionic surfactants with magnetic counterions, surfactants with the magnetic moiety chelated in the surfactant unimer, and block copolymer amphiphiles with multiple magnetic moieties. Our research shows that the strength of association of the paramagnetic moiety with the amphiphilic components in an aqueous environment is dependent upon the type of complex that contains the ferromagnetic ion. Utilizing electrochemical methods, we quantitatively determined the stability of the association between cationic and anionic surfactants with a corresponding magnetic counterion in aqueous solution and examined the effect the stability of the association has on the magnetic response. Additionally, we examined the ability of the magnetic surfactants to alter the surface tension at the air-water interface in response to a magnetic field and found that the ability to alter interfacial properties is strongly dependent upon not only the strength of the association between the magnetic and surfactant moieties of the amphiphilic molecules but also the stability of the magnetic moiety.

Development of magnetic surfactants for low energy separations: Effect of surfactant stability on magnetic response

2019 Spring National Meeting

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