Competitive adsorption and gas diffusion inhibition effect between long-chain alcohol and short-chain fluorocarbon surfactant in foam solution

Abstract

Long-chain alcohols offer remarkable potential for foam stabilization due to their biocompatibility and amphiphobic characteristics. However, their impact on fluorocarbon surfactant systems remains insufficiently explored. This study chose 1-octanol, 1-decanol, and 1-dodecanol as stabilizers, investigating their effects on surface activity, interfacial activity, spreading performance, viscosity, bubble evolution, and drainage property in foam solution containing short-chain fluorocarbon surfactant. The result indicates that long-chain alcohols competitively displace surfactants at interfaces, reducing surface and interfacial activities. Meanwhile, interfacial alcohol adsorption elevates surfactant concentration in aqueous phase, promoting surfactant/alcohol micellization and increasing viscosity. 1-Dodecanol, with high hydrophobicity, triggers phase separation above 3 mmol/L, inducing the highest viscosity elevation. Long-chain alcohols exert dual effects on bubble evolution, with critical concentrations (1-octanol: 3 mmol/L, 1-decanol: 1 mmol/L, 1-dodecanol: 1 mmol/L) serving as thresholds. At or below these thresholds, interfacial alcohol adsorption and synergistic micellization strengthen foam films and inhibit gas diffusion, retarding bubble coarsening. Above thresholds, excessive alcohols accelerate bubble rupture. The drainage analysis reveals that 1-octanol and 1-decanol effectively stabilize foam through viscosity enhancement and coarsening inhibition, while 1-dodecanol exacerbates foam drainage and destabilization. The foam solution with 3 mmol/L 1-octanol exhibits the optimal characteristics, with a surface tension of 22.00 mN/m, 25 % drainage time of 61.83 s, and spreading coefficients of 4.27 mN/m with diesel and 3.28 mN/m with cyclohexane. This study provides references for the application of long-chain alcohols as foam stabilizers in fluorocarbon surfactant systems, establishing a foundation for developing environmentally friendly aqueous film-forming foam.