Magnetic Gemini Surfactants

Abstract

A homologous series of Gemini surfactants, dimethylene-1,2-bis­(alkyldimethyl-ammonium bromide) (referred to as n-2-n·2Br, n = 14, 16, and 18) and Fe- or lanthanide metal-based magnetic Gemini surfactants (abbreviated as n-2-n·2X, X = Fe, Ce, and Gd), were first synthesized. Measurements of surface tension and electrical conductivity determine the physical quantities related to the surface activities of n-2-n·2Br and n-2-n·2X, and the magnetic behaviors of n-2-n·2X are elucidated by superconducting quantum interference device magnetometry. Thermogravimetric analysis and differential scanning calorimetry have been used to investigate thermotropic liquid crystalline properties of all aforementioned surfactants, and the liquid crystal textures were further observed via polarizing optical microscopy. These results reveal that for magneto-responsive Gemini surfactants, both magnetic counterions and alkyl chain lengths have certain effect on surface activities, magnetism, and thermotropic phase behavior. We summed up these changes and discussed the causes, which could provide a new insight into controlling the properties of magnetic surfactants.

Ionic liquid crystals based on amino acids and gemini surfactants: tunable phase structure, circularly polarized luminescence and emission color

“…Deionized water with a resistivity of 18.25 MΩ cm was obtained from a UPH-IV ultrapure water purifier (China). All gemini surfactants with diverse spacer groups were synthesized according to the literature, 49,52,53 and their chemical structures and corresponding abbreviations are depicted in Fig. S1 (ESI†).…”

“…Gemini surfactants generally feature abundant thermotropic behavior at the thermal annealing. 48–50 Their double chains provide sufficient molecular flexibility to suppress crystallization, and their spacer group as a unique component segment affects the phase structure and transition temperature of ILC. 51 Consequently, gemini surfactants are deemed to be favorable candidates to make up the flexible parts in CPL-active ILCs.…”

K+, Sr2+-Triggered Phase Transitions from Chiral Thermotropic Liquid Crystalline to G-Quadruplex CTLC with Circularly Polarized Luminescence

“…Gemini surfactants (n−2−n•2Br) were synthesized according to relevant literature. 33 2.2. Preparation of the n-GMP Complexes.…”

Amphiphilic Au Nanoclusters Modulated by Magnetic Gemini Surfactants as a Cysteine Chemosensor and an MRI Contrast Agent

“…In addition, deionized water with a resistivity of 18.25 MΩ·cm obtained from a UPH-IV ultrapure water purifier (China) was utilized throughout the whole experimental process. Gemini surfactants n-s-n·2Br and mag-G-surfs 14-2-14·2X were synthesized according to relevant literature studies; − the detailed synthesis routes and 1 H NMR spectra are described in the Supporting Information (Figures S1 and S2).…”