| Vesicles have received extensive investigation on simulating cellmembranes for their similar ordered bilayer structures. Other applicationscan be found in drug or gene carrier or as microreactor. To date, vesiclesare fabricated mainly by surfactants or amphiphilic block copolymers.Conventionally, surfactants are mixed to produce vesicles, generally foranionic surfactants and cation surfactants. However, precipitation is easilyformed especially for equimolar mixture. On the other hand,one-component surfactants,such as gemini or bola type, often involvecomplicated synthesis process. Thus, it is always a hot but challengingfield to obtain vesicles in a simple way.Supramolecular amphiphiles (SAs) are fabricated by non-covalentsynthesis. Therefore, it avoids tedious covalent synthesis procedures. Inaddition, the self-assembly and disassembly of SAs can be easilymanipulated by external conditions, making them as promising responsivematerials. However, the fruits are still green and a lot of work needs to bedone before harvest. Further work should be devoted to exploring newways to fabricating SAs, investigating their self-assembly behavior andpotential applications.In this study, we fabricated novel SAs through proton-transferhydrogen bonding. The SAs have a gemini topology but are connected bynon-covalent interactions. Compared to the system of anionic/cation surfactants, SAs do not form precipitation. In organic and aqueoussolutions, a serious of novel aggregates are formed including compoundmicelles, multimeric micelles, worm micelles, vesicles, Janus particles,yolk-shell micelles,nano-sheets and microspheres with micro-nano-binarystructure. The chemically reactive micelles can be used as template tosynthesize organic-inorganic hybrid hollow spheres and polymericyolk-shell particles by introducing inorganic crosslinker phosphonitrilicchloride trimer. Besides, polyphosphazene microtubes are also prepared byin suit template synthesis. The detailed contents are summarized below.(1) Gemini-like SAs are constructed by mixing bis(4-mercaptophenyl)sulfide (MPS) with tertiary amine at a molar ratio of1:2. The tertiaryamines include triethylamine (TEA), N,N’-Dimethylhexadecylamine(DMA16). The self-assembly behavior of complexes MPS/TEA andMPS/DMA16in organic solutions are investigated and they are found toform micelles and vesicles.(2) Complexes MPS/TEA could form yolk-shell micelles intetrahydrofuran, which is a new micellar architecture that has not beenreported before. By introducing crosslinker phosphonitrilic chloride trimer.,polymeric yolk-shell particles are obtained which further demonstrate thiskind of micelles. At a high concentration (above20mM), asymmetricparticles are formed, such as Janus particles and patchy particles. Inaddition, nanosheets and microspheres with micro-nano-binary structureare obtained when the solution of MPS/TEA in acetone ordimetbylformamide is ultrasonic treated and stands aging for a periodrespectively. (3) Complexes MPS/DMA16form micelles at a low concentration inaqueous solution. Vesicles are produced at a high concentration. Previousmixture system mainly involves anionic/cation surfactants. However, weadopted non-ionic tertiary amine and non-surface-active molecule tofabricate SAs and obtained vesicles, which shed a new light on access tovesicles and novel self-assembly structures.(4) We discussed the formation and structures of the formed micelles,vesicles and asymmetric particles. Concentration and aging effects onmorphologies are investigated. Complexes MPS/TEA show a richaggregation behavior due to short chains of TEA. At low concentrations,vesicles are formed and asymmetric particles are formed at highconcentrations. After a long aging time, worm-like and multimetricmicelles are found which may be caused by fusion and oxidation ofsulfhydryl groups.(5) Hollow polyphosphazene microspheres (PCTS-HMs) are prepared bycrosslinking the surface of MPS/TEA micelles. The size of cavity can becontrolled by adding different amount of crosslinker, phosphonitrilicchloride trimer. The solvent effects on morphologies are studied. Inacetonitrile, multicompartment PCTS-HMs are obtained. Intetrahydrofuran, we obtained microtubes (PCTS-MTs) at highconcentrations. The formation mechanism of polyphosphazene microtubesis different from that of the PCTS-HMs. In our previous work, we preparedpolyphosphazene nanotubes via in suit triethylamine hydrochloride template. Similarly, PCTS-MTs are synthesized through in suittriethylamine hydrochloride micro-rod template that are formed byadhesion of polymer-coated nano-rod of triethylamine hydrochloride.PCTS-HMs have excellent thermal and mechanical stability, goodbiological compatibility, which make them very promising in applicationsof catalyst, drug carrier, microreactor and chemical sensors. |
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