Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, Shandong 250100, PR China.
Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, PR China; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
J Colloid Interface Sci. 2019 Feb 15;536:381-388. doi: 10.1016/j.jcis.2018.10.040. Epub 2018 Oct 16.
To obtain surfactants with superior surface activity and responsive behavior, "pseudogemini" surfactants (short for D-LCFA) are synthesized by mixing long chain fatty acids (LCFA) and polyetheramine D 230 at fixed molar ratio (2:1). Non-covalently bonded building blocks indicate that CO-responsive aqueous foams can be obtained by utilizing such pseudogemini surfactants.
H NMR and FT-IR characterizations prove that the building blocks of these surfactants are associated by electrostatic interaction. The synthesis (Brønsted acid-base reaction) is simple and eco-friendly. "Pseudogemini" structure enables D-LCFA to reduce surface tension of aqueous solution effectively, thus facilitating foam generation. Rheograms, FF-TEM and Cryo-TEM results prove that different aggregates in D-LCFA aqueous solutions lead to different foam properties.
Bubbling of CO for about 30 s leads to the rupture of aqueous foams generated by D-LCFA, while removing CO by bubbling of N at 65 °C for 10 min enables re-generation of foams. The CO-responsive foaming properties can be attributed to dissociation of D-LCFA upon bubbling of CO and re-association upon removal of CO. The effective CO-responsive foams can be applied to many areas, such as foam fracturing, foam enhanced oil recovery or recovering of radioactive materials.
为了获得具有卓越表面活性和响应行为的表面活性剂，通过将长链脂肪酸 (LCFA) 和聚醚胺 D230 以固定摩尔比（2:1）混合来合成“拟双子”表面活性剂（简称 D-LCFA）。非共价键合的结构单元表明，可以通过使用这种拟双子表面活性剂获得对 CO 响应的水基泡沫。
H NMR 和 FT-IR 特性证明了这些表面活性剂的结构单元是通过静电相互作用结合在一起的。该合成（Brønsted 酸碱反应）简单且环保。“拟双子”结构使 D-LCFA 能够有效地降低水溶液的表面张力，从而促进泡沫的生成。流变图、FF-TEM 和 Cryo-TEM 结果证明，D-LCFA 水溶液中的不同聚集态导致了不同的泡沫性能。
CO 的鼓泡约 30 秒导致由 D-LCFA 生成的水基泡沫破裂，而通过在 65°C 下鼓泡 N 去除 CO 则可以使泡沫重新生成。CO 响应的起泡性能归因于 CO 鼓泡时 D-LCFA 的解离以及 CO 去除时的重新结合。有效的 CO 响应性泡沫可应用于许多领域，例如泡沫压裂、泡沫驱油或放射性物质的回收。
