One-step synthesis, wettability and foaming properties of high-performance non-ionic hydro-fluorocarbon hybrid surfactants

In this work, a series of non-ionic hydro-fluorocarbon hybrid surfactants (C9F19CONH(CH2)(3)N(CmH2m+1)(2), abbreviated as C(9)F(19)AM (m = 1), C(9)F(19)AE (m = 2) and C(9)F(19)AB (m = 4) were easily synthesized by one-step reaction and characterized by (HNMR)-H-1, (FNMR)-F-19 and MS spectroscopy. Unlike conventional non-ionic surfactants (most hydrophilic units consisted of hydroxy or ether groups), their hydrophilic groups were composed of amide group, an eco-friendly unit. The surface activity, wettability, thermal stability and foaming performance were investigated. The results showed that the C(9)F(19)AE(C9F19CONH(CH2)(3)N[CH2CH3](2)) had superior surface and interface activities, which could reduce the surface tension of water down to 15.37 mN/m and the inter facial tension (cyclohexane/water/surfactants) to 5.8 mN/m with a low cmc (critical micelle concentration) of 0.12 mmol/L. Through the calculation of A min (the minimum area occupied per-surfactant molecule), we speculated this higher surface activity was related to the compatibility between hydrocarbon and fluorocarbon chains. When used as wetting and foaming agents, the C-9 F-19 AE also outperformed great advantages over conventional non-ionic fluorocarbon and hydrocarbon surfactants, which could decrease the contact angle of water on PTFE plate from 107.7 degrees to 3.6 degrees, and increase the foam integrated value F to 536 500 +/- 3066.5 mLs. Moreover, the decomposition temperature (T-d ) of C9F19 AE could reach up to 173 degrees C. This work demonstrates a valuable strategy to develop a kind of high-efficiency foaming agent via facile synthesis. (C) 2017 Elsevier B.V. All rights reserved.