Mixed fluorinated–hydrogenated surfactant-based system: Preparation of ordered mesoporous materials

• Published in: Journal of colloid and interface science Vol. 302; no. 2; pp. 643 - 650
• Main Authors: Blin, J.L., Henzel, N., Stébé, M.J.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15.10.2006; Elsevier
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; Fluorinated surfactant; General and physical chemistry; Hydrogenated surfactant; Mesoporous; Mixed system; Nonionic surfactant; Phase diagram; Porous materials; Silica; Phase diagram; Fluorinated surfactant; Mixed system; Hydrogenated surfactant; Mesoporous; Silica; Nonionic surfactant; Non ionic surfactant; Fluorine compound; Surfactant; Porous material; Mesoporosity; Preparation
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2006.07.002

We have investigated a mixed fluorinated–hydrogenated surfactant-based system [C 8F 17C 2H 4(OC 2H 4) 9–C 12H 25(OC 2H 4) 8] in water. The phase diagram exhibits that the micellar domain can be divided into three parts: above 80 wt% of water both hydrogenated and fluorinated surfactants are completely miscible and they formed mixed micelles in all proportion. When the water concentration is decreased from 80 to 60 wt% a gap of miscibility appears and two micellar zones, one fluorocarbon-rich micelles and one hydrocarbon-rich micelles are observed. The liquid crystal domain is composed of one fluorocarbon-rich (H F 1) and one hydrocarbon-rich (H H 1) hexagonal phase. The hydrophobic radius and the cross-sectional area remain constant in the H H 1 and in the H F 1 domains. Moreover, SAXS measurements proved that the hydrophobic chains in the liquid crystal phases adopt rather an extended conformation. Then the mixture of surfactants was used as template for the preparation of mesoporous materials. Mesostructured silicas with a well hexagonal array of their channels were prepared via a cooperative templating mechanism (CTM), if the loading of fluorinated surfactant is larger than 50%. Decreasing the proportion of the fluorinated amphiphile in the mixture leads to the formation of mesoporous silica with a disordered structure. In this case the channel arrangement is no longer governed by the fluorinated surfactant but by the hydrogenated one. A mixed fluorinated–hydrogenated surfactant-based system in water has been investigated for the preparation of mesoporous materials. Fluorinated surfactant governed the channel arrangement if its concentration is higher than 50%.