Effects of double hydrophilic head groups on the thermodynamic parameters, aggregation behavior, and foam characteristics of amino acid-based fluorocarbon surfactants

Abstract

This paper presents an innovative fluorocarbon surfactant architecture that synergistically merges the superior surface activity of fluorocarbon surfactants with the environmental compatibility of biodegradable amino acid surfactants. Through this molecular design strategy, a series of amino acid-based fluorocarbon surfactants (TDAFB, GAFB, and BAFB) that inherit the advantageous characteristics of both constituent materials have been successfully synthesized. On this basis, compared to GAFB and BAFB with a single hydrophilic head group, the performance of TDAFB with double hydrophilic head groups should be significantly affected. Research demonstrates that all three compounds display outstanding surface activity. Nevertheless, TDAFB exhibits higher surface tension (γ_CMC = 21.18 mN/m) and critical micelle concentration (CMC = 0.009926 mol/L), attributable to the larger A_min and the stronger electrostatic repulsion of the double hydrophilic head groups. Furthermore, the double hydrophilic head groups also significantly affect physical and chemical characteristics of TDAFB, encompassing solubility, molecular aggregation behavior, as well as emulsion and foam stabilization capacities. In contrast, despite exhibiting a marginally lower dissolution rate, BAFB with a single hydrophilic head group is superior to TDAFB with the double hydrophilic head groups across all other metrics. This review provides a new approach for the development of novel environmentally friendly fluorocarbon surfactants.