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

Abstract

Abstract In this work, a series of non-ionic hydro-fluorocarbon hybrid surfactants (C 9 F 19 CONH(CH 2 ) 3 N(C m H 2m+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 1 HNMR, 19 FNMR 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 (C 9 F 19 CONH(CH 2 ) 3 N[CH 2 CH 3 ] 2 ) had superior surface and interface activities, which could reduce the surface tension of water down to 15.37 mN/m and the interfacial 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° to 3.6°, and increase the foam integrated value F to 536 500 ± 3066.5 mL s. Moreover, the decomposition temperature (T d ) of C 9 F 19 AE could reach up to 173 °C. This work demonstrates a valuable strategy to develop a kind of high-efficiency foaming agent via facile synthesis.