Effect of Hydrocarbon Parts of the Polar Headgroup on Surfactant Aggregates in Gemini and Bola Surfactant Solutions

Abstract

Cationic gemini surfactant homologues alkanediyl-alpha,omega-bis(dodecyldiethylammonium) bromide, [C12H25(CH3CH2)2N(CH2)SN(CH2CH3)2C12H25]Br2, where S = 4, 6, 8, 10, or 12, referred to as C12CSC12(Et), and cationic bolaamphiphiles BPHEAB (biphenyl-4,4'-bis(oxyhexamethylenetriethylammonium) bromide), PHEAB (phenyl-4,4'- bis(oxyhexamethylenetriethylammonium) bromide) were synthesized, and their aggregation behaviors in aqueous solution were studied and compared by means of dynamic light scattering, fluorescence entrapment, and transmission electron microscopy. Spherical vesicles were found in the aqueous solutions of these gemini and bola surfactants, which can be attributed to the increase of the hydrocarbon parts of the polar headgroup of the surfactants. In combination with the result of the other gemini with headgroup of propyl group, the increase of the hydrophobic parts of the surfactant polar headgroup will be beneficial to enhance the aggregation capability of the gemini and bola surfactants. Both of the vesicles formed in the gemini and bola systems showed good stabilities with time and temperature, but different stability with salt due to the different membrane conformations of surfactant molecules in the vesicles.

Review on chemically bonded geminis with cationic heads: second-generation interfactants

“…A good balance between electrostatic, van der Waals, hydrophobic, and steric interactions affect the aggregation behaviors of such surfactants. Micellization involving spherical vesicles can be found in the aqueous solutions of gemini and bola surfactants, which can be attributed to the increase of the hydrocarbon parts of the polar head group of the surfactants [75].…”

Surfactant effects on the microstructures of Fe3O4 nanoparticles synthesized by microemulsion method

“…(d) New Gemini surfactant: As a new class of surfactants, Gemini surfactants have attracted increasing attention in both academic and industrial circles over the last years, owing to their superior properties in comparison with those of conventional single-chain surfactants [43][44][45][46][47]. About Gemini surfactants, there have the relevant reports on the application of template synthesis of various materials, such as gold particles and organized mesoporous silica [48][49][50].…”

A gemini-type superspreader: Synthesis, spreading behavior and superspreading mechanism

“…The surface tension of aqueous superspreader solutions at the critical aggregation concentration (CAC) is relatively low (20)(21)(22)(23)(24)(25) mN/m) [7,8], but not lower than that of fluorosurfactants (18-28 mN/m) [9]. However, trisiloxane-based surfactants promote the rapid spreading of water droplets over hydrophobic surfaces and even wet them completely.…”

“…These surfactants have evoked intense interest, both academic and industrial, because of their unique properties compared to conventional singleheaded and single-tailed surfactants, including lower CAC values (by approximately an order of magnitude), increased surface activity and lower surface tension at the CAC [22]. Many studies have investigated the relationship between the molecular structure of gemini surfactants and their properties [22][23][24][25]. However, research on the effect of the structural variation of gemini surfactants on superspreading behavior is still rare.…”