Synthesis and Surface Properties of Polyether‐Based Silicone Surfactants with Different Siloxane Groups

Research Progress in Structure Synthesis, Properties, and Applications of Small-Molecule Silicone Surfactants

Silicone surfactants have garnered significant research attention owing to their superior properties, such as wettability, ductility, and permeability. Small-molecular silicone surfactants with simple molecular structures outperform polymeric silicone surfactants in terms of surface activity, emulsification, wetting, foaming, and other areas. Moreover, silicone surfactants with small molecules exhibit a diverse and rich molecular structure. This review discusses various synthetic routes for the synthesis of different classes of surfactants, including single-chain, "umbrella" structure, double chain, bolaform, Gemini, and stimulus-responsive surfactants. The fundamental surface/interface properties of the synthesized surfactants are also highlighted. Additionally, these surfactants have demonstrated enormous potential in agricultural synergism, drug delivery, mineral flotation, enhanced oil recovery, separation, and extraction, and foam fire-fighting.

Silicone polyether surfactant enhances bacterial cellulose synthesis and water holding capacity

The versatility and unique properties of bacterial cellulose (BC) motivate research into enhancing its synthesis. Here a silicone polyether surfactant (SPS) was synthesized and tested as a non-nutritional additive to the cultivation media of Komagataeibacter xylinus. The addition of SPS to the Hestrin-Schramm (HS) medium resulted in a concentration-dependent decrease in surface tension from 59.57 ± 0.37 mN/m to 30.05 ± 0.41 mN/m (for 0.1% addition) that was correlated with an increased yield of BC, up to 37% wet mass for surfactant concentration close to its critical micelle concentration (0.008%). Physicochemical characterization of bacterial cellulose obtained in presence of SPS, showed that surfactant is not incorporated into BC structure and has a moderate effect on its crystallinity, thermal stability. Moreover, the water holding capacity was enhanced by over 40%. Importantly, obtained BC did not affect L929 murine fibroblast cell viability. We conclude that SPS provides an eco-friendly approach to increasing BC yield in static culture, enabling more widespread industrial and biomedical applications.

Thermodynamic Analysis of Trisiloxane Surfactant Adsorption and Aggregation Processes

The trisiloxane polyether surfactant (3-[3-(hydroxy)(polyethoxy)propyl]-1,1,1,3,5,5,5 -heptamethyltrisiloxane) (TS-EO12) was successfully synthesized by a hydrosilylation reaction in the presence of Karstedt catalyst. The structural analysis of the surfactant was done by ¹H-NMR, ¹³C-NMR, ²⁹Si-NMR and FT-IR analysis. In addition the thermal stability of TS-EO12 was studied by the thermogravimetric measurements. On the one hand the surface properties of TS-EO12 at the water-air interface were investigated by surfactant aqueous solutions surface tension measurements carried out at 293 K, 303 K and 313 K, and on the other the aggregation properties were analyzed based on the solubilization properties of TS-EO12 aggregates at different temperatures. On the basis of the obtained thermodynamic parameters of adsorption and micellization of studied surfactant the temperature impact on its surface and volume properties were deduced. It was proved that the tendency of the studied surfactant molecules to adsorb at the water-air interface and to form micelles weakens with decreasing temperature. It was also concluded that the structure of the adsorption layer changes with temperature. Optical microscopy measurements were used for the TS-EO12 micelle morphology determination.

"Umbrella" Structure Trisiloxane Surfactant: Synthesis and Application for Reverse Flotation of Phosphorite Ore in Phosphate Fertilizer Production

Phosphorite is generally used in the manufacture of phosphate fertilizer and plays a vital role in the development of agricultural and food production. Nonetheless, how to obtain phosphorite concentrates efficiently and sustainably has become an urgent problem. In this study, a newly designed trisiloxane surfactant, N-(2-Aminoethyl)-3-aminopropyltrisiloxane (AATS), has been prepared and utilized as an emerging collector for reverse flotation of phosphorite ore. Its collecting ability was compared with the conventional surfactant 1-dodecamine (DDA). In the collector concentration tests, AATS with lower concentrations showed stronger collecting ability for quartz. In the pH tests, AATS always performed better than DDA in the acidic or alkaline condition. In bench-scale flotation experiments, the P₂O₅ recovery of phosphorite concentrates with 150 g/t AATS was 10.77% higher than that with 300 g/t DDA, which proved that AATS can be applied to the sustainable production of phosphorite concentrates. For a 4000 t/d phosphorite ore processing plant, the profit could be increased 7,014,702.07 USD every year by using AATS as the collector. Therefore, this work provides a promising approach to enhance the production efficiency of phosphate fertilizer and to promote the sustainable development of agriculture.