Dynamic Surface Properties of Eco-Friendly Cationic Saccharide Surfactants at the Water/Air Interface

Abstract

The equilibrium surface properties and dynamic surface tension (DST) are presented for aqueous solutions of novel eco-friendly cationic saccharide surfactants (CnDGPB) at different concentrations and temperatures. The equilibrium surface tension, the DST, the effective diffusion coefficients and the activation barrier of the surfactants are calculated and analyzed. In addition, the general diffusion mechanism of the surfactants is proposed. The equilibrium surface tension results show that the γCMC and CMC values decrease with increasing temperature. The interactions (repulsion forces) between the hydrophobic groups and water molecules decrease with increasing temperature, which results in increased HLB values. This phenomenon causes a higher Amin and lower Γmax. The DST of CnDGPB below and above the CMC is tested by the maximum bubble pressure method at temperature from 25 °C to 45 °C. The adsorption activation energy of CnDGPB is between 3 kJ/mol and 20 kJ/mol. The results show that the final stages of the DST decays are consistent with the activated diffusion-controlled adsorption mechanism.

Surface Activity, Wetting, and Aggregation of a Perfluoropolyether Quaternary Ammonium Salt Surfactant with a Hydroxyethyl Group

“…Contrarily, at higher concentrations of PFPE-C (such as, 2 mmol/L), the contact angles on PTFE were smaller than those on paraffin films, possibly due to the high structural similarity of the PFPE-C hydrophobic chain with PTFE. Surfactant molecules are more easily ranked on PTFE [32,33]. Moreover, aqueous solutions of PFPE-C at concentrations higher than 0.1 mmol/L can almost wet PTFE and paraffin membranes, indicating that PFPE-C has superior wetting properties on low surface energy materials compared with conventional hydrocarbon surfactants.…”

Surface Activity, Wettability, and Aggregation Behavior of Ecofriendly Fluorocarbon Surfactant Based on Double Perfluorinated Branched Short Chains

“…If the concentration is increased, then the free movement of molecules would be greatly restricted. Significantly, the D eff / D s ratios for all four cases are much greater than 1, which indicates that the adsorption process of the aqueous solution of SFDC and the SFDC/HTAB mixture is the diffusion-controlled adsorption mechanism …”

“…Significantly, the D eff /D s ratios for all four cases are much greater than 1, which indicates that the adsorption process of the aqueous solution of SFDC and the SFDC/HTAB mixture is the diffusioncontrolled adsorption mechanism. 43 ■ CONCLUSIONS This paper describes the synthesis of a novel environmentally friendly sulfonate fluorocarbon surfactant (SFDC) with dual perfluorobranched short chains, using the budget industrial raw material D 2 as the initial raw material, followed by the structural characterization by FT-IR and NMR. The surface activity, aggregation behavior, wettability, and thermodynamic behavior of SFDC and SFDC/HTAB are investigated on this basis.…”