Colloidal Wormlike Micelles with Highly Ferromagnetic Properties

For the first time, a new fabrication method for manipulating the ferromagnetic property of molecular magnets by forming wormlike micelles in magnetic-ionic-liquid (mag-IL) complexes is reported. The ferromagnetism of the mag-IL complexes was enhanced 4-fold because of the formation of wormlike micelles, presenting new evidence for the essence of magnetism generation at a molecular level. Characteristics such as morphology and magnetic properties of the wormlike micelle gel were investigated in detail by cryogenic transmission electron microscopy (Cryo-TEM), rheological measurements, circular dichroism (CD), FT-IR spectra, and the superconducting quantum interference device method (SQUID). An explanation of ferromagnetism elevation from the view of the molecular (ionic) distribution is also given. For the changes of magnetic properties (ferromagnetism elevation) in the wormlike micelle systems, the ability of CTAFe in magnetizing AzoNa₄ (or AzoH₄) can be ascribed to an interplay of the magnetic [FeCl₃Br]⁻ ions both in the Stern layer and in the cores of the wormlike micelles. Formation of colloidal aggregates, i.e., wormlike micelles, provides a new strategy to tune the magnetic properties of novel molecular magnets

Phase Structure Transition and Properties of Salt-Free Phosphoric Acid/Non-ionic Surfactants in Water

Precise control of phase structure transition for the synthesis of multi-dimensional soft materials is a fascinating target in amphiphilic molecule self-assembly. Here, we demonstrate a spontaneous formation of a closely packed lamellar phase consisting of uni- and multi-lamellar vesicles through the incorporation of a small amount of an extractant, di­(2-ethylhexyl)­phosphoric acid (DEHPA), into the highly swollen, planar lamellar phase of a non-ionic tetraethylene glycol monododecyl ether (C₁₂EO₄) surfactant in water. It is figured out that the introduction of negative membrane charges results in the electrostatic repulsion among the lamellae, which suppresses the Helfrich undulation and induces a phase structure transition from planar lamellae to closely packed vesicles. Our results provide important insight into amphiphilic molecule self-assembly, where additives and pH can satisfy the opportunities for the precise tuning of the lamellar structures, which makes a way for the development of lamellar soft materials

Self-Assembled Magnetic Viruslike Particles for Encapsulation and Delivery of Deoxyribonucleic Acid

Developing nontoxic artificial carriers for stimuli-responsive capture, transport, and delivery of biomolecules is of immense scientific interest. Herein, for the first time, we synthesize a double-tailed cationic surfactant, (C₁₆H₃₃)₂(CH₃)₂N⁺[FeCl₃Br]⁻, which possesses magnetic properties [magnetic surfactants (Mag-Surfs)]. The time-dependent formation of virus-shaped hybrid mixed assemblies of polyoxometalates (POMs) {Mo₇₂Fe₃₀}/Mag-Surf with hollow-shell structures is followed. These structures serve well as robust high-surface-area shuttles, which can be manipulated with applied magnetic fields. By using cationic Mag-Surfs, the anionic POMs and DNA can be complexed in these ternary mixtures. These virus-shaped complexes act as nanoanchors and nanomotors, which can be utilized for binding, anchoring, and delivery of biomolecules, such as DNA. It is found that they have a good absorption capacity for DNA and myoglobin over 24 h, after application of a magnetic field. The realization of magnetic virus-shaped {Mo₇₂Fe₃₀}/Mag-Surf spheres may open possibilities for designing other functional nanoparticles, allowing effective control over the delivery/separation of biomolecules

Self-Assembled Magnetic Viruslike Particles for Encapsulation and Delivery of Deoxyribonucleic Acid

Developing nontoxic artificial carriers for stimuli-responsive capture, transport, and delivery of biomolecules is of immense scientific interest. Herein, for the first time, we synthesize a double-tailed cationic surfactant, (C₁₆H₃₃)₂(CH₃)₂N⁺[FeCl₃Br]⁻, which possesses magnetic properties [magnetic surfactants (Mag-Surfs)]. The time-dependent formation of virus-shaped hybrid mixed assemblies of polyoxometalates (POMs) {Mo₇₂Fe₃₀}/Mag-Surf with hollow-shell structures is followed. These structures serve well as robust high-surface-area shuttles, which can be manipulated with applied magnetic fields. By using cationic Mag-Surfs, the anionic POMs and DNA can be complexed in these ternary mixtures. These virus-shaped complexes act as nanoanchors and nanomotors, which can be utilized for binding, anchoring, and delivery of biomolecules, such as DNA. It is found that they have a good absorption capacity for DNA and myoglobin over 24 h, after application of a magnetic field. The realization of magnetic virus-shaped {Mo₇₂Fe₃₀}/Mag-Surf spheres may open possibilities for designing other functional nanoparticles, allowing effective control over the delivery/separation of biomolecules

Self-Assembled Switching Gels with Multiresponsivity and Chirality

A multiresponsive hydrogel material consisting of a commercial cationic surfactant and an azobenzene derivative functionalized with four carboxylic acid groups was constructed. The achiral azobenzene molecule as a gelator produces chirality at the supramolecular level in the presence of H⁺. The acid-induced gelation and morphology change of supramolecular gels were investigated in detail by cryogenic transmission electron microscopy (cryo-TEM), rheological measurements, circular dichroism (CD), and ¹H NMR spectra. Based on the results, a mechanism of the intermolecular H-bond-directed gelation and supramolecular chirality was proposed. Other than the pH sensitivity, the microstructure and the chirality of the hydrogel demonstrate reversible switching behavior in response to photoirradiation, on account of the photoisomerization of the azobenzene derivative. Accordingly, a chiroptical switch comprising four different states in response to pH and light stimuli is strategically constructed. Not only does the present system provide a good opportunity for investigating the gelation-induced supramolecular chirality by symmetry breaking totally based on achiral molecules, but it also proposes a new strategy to build multiresponsive supramolecular switches as particularly attractive for the future development of functional materials