Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (8): 1655-1664.doi: 10.3866/PKU.WHXB201704193

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Vesicle Gels of Magnetic Asymmetric Surfactants

Wen-Rong ZHAO1,Jing-Cheng HAO1,*()   

  1. 1 Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan 250100, P. R. China
    2 Physikalische Chemie Ⅰ, Bayreuth University, D-95440, Germany
  • Received:2017-02-28 Published:2017-06-14
  • Contact: Jing-Cheng HAO
  • Supported by:
    the National Natural Science Foundation of China(2140102006);the Specialized Research Fund for the Doctoral Program of Higher Education, China(20130131130005)


This report details the synthesis of a series of special magnetic cationic surfactants that contained two asymmetric alkyl chains, cetylpentyldimethylammonium trichloromonobromoferrate (C16C5DMA+[FeCl3Br]-). The fabrication of magnetic, adhesive, poly-morphological bilayer vesicle gels with unpredictable curvature and high flexibility was investigated in detail. These colloidal bilayer nano-transformers self-adhered to form a string; they also exhibited transformable morphologies that were investigated using cryo-transmission electron microspcopy (TEM), freezing-fracture transmission electron microscopy (FF-TEM), rheological analysis, Fourier transform infrared spectrometry (FT-IR), and superconducting quantum interference device (SQUID) techniques. Significantly, the deformed vesicles cohered to the gibbous bilayer protrusions, which closely resembled the pseudopodia of Proteus. These bilayer nano-transformers were capable of imitating structures and outlines of the natural world that, through human imagination, ranged from the island of Sicily in Italy to the larva of the Clanis bilineata and the common peanut. Most of the bilayer nano-transformers were endowed with unpredictable multi-curvature and high flexibility. A mechanism for the interlocking of the long and short alkyl chains in a bilayer arrangement was proposed in this study. The short chains departed from the bilayer to protrude externally; then, they associated non-covalently into inter-vesicular patches because of their hydrophobic interactions. Consequently, the hydrophobic inter-vesicular patches could supersede the repulsion between the vesicle membranes and allowed the vesicles to cohere. Of equal importance was that the anions[FeCl3Br]- could not only impart magnetism to the transformable vesicles, but could also tune the organization through the arrangements of the alkyl chains during the assembly process. Thus, the poly-morphology, adhesiveness, and curvature protrusions of this astounding colloidal "proteus" are eminently exploitable. This not only revealed the rudimentary regulatory mechanism of the membrane curvature, but also provided clues for the advancement of artificial cell fabrication.

Key words: Asymmetric surfactant, Cohesive vesicle, Magnetic gel, Bilayer, Multi-curvature


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