Hydrogenated and fluorinated host-guest surfactants: complexes of cyclodextrins with alkanes and fluoroalkyl-grafted
Zeng-Pei Dou1, Hang Xing, Jin-Xin Xiao
1Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
Abstract:
A novel type of surfactants named "host-guest surfactants" were designed and synthesized. The headgroup and hydrophobic tail of the new surfactants are connected by supramolecular interactions rather than covalent bonds. The inclusion complexes of a series of cyclodextrins (CDs) and alkanes/fluoroalkyl-grafted alkanes were synthesized and measured by surface tension, XRD, XPS, TGA, and NMR spectroscopy. The methyl-β-CD/hexadecane complex showed surface activity relative to those conventional hydrogenated surfactants. For the inclusion complex of hydroxypropyl-α-CD/C(8)F(17)SO(2)NHC(8)H(17), the structure was locked by subtle intermolecular recognition, which ensured the surprising surface activity similar to common excellent fluorinated surfactants. This surfactant, which was fabricated from nonsurface-active even insoluble components, showed the prospect that its surface activity might also be destroyed by introducing appropriate small species to extrude the guest from the cavity.
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