Lin Feilin, Zhang Mengjie, Ren Huaye, Tang Fangfang, Zhu Jie, Jiang Jianzhong
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Material Engineering, Jiangnan University, 1800 Lihu Road, Wuxi, China.
The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Material Engineering, Jiangnan University, 1800 Lihu Road, Wuxi, China.
Int J Biol Macromol. 2025 Sep;322(Pt 2):146757. doi: 10.1016/j.ijbiomac.2025.146757. Epub 2025 Aug 10.
Demulsification is necessary for the emulsions requiring temporary stabilization. However, the amphiphilicity of emulsifiers can create challenges for demulsification, and their residue in oil phase can also impair the oil quality. Herein, we describe a CO-switchable Pickering emulsions stabilized by chitosan aggregates (CAs), in which the emulsifiers could be recycled and reused in water. Various oils, including crude oil, could be emulsified by CAs (0.05 wt%) at pH greater than pK value (acid dissociation constant of the conjugated acid, e.g., pH 6.5). CO₂-triggered reversible transformation between CAs and hydrophilic polymer chains (CCs) facilitated not only rapid demulsification (≤10 min) but also complete recycling of the emulsifier in water, with no residue in the oil. The interfacial tension of the separated oil after 6 cycles was comparable to that of fresh oil (50.2 ± 1.0 mN/m). Elemental analysis of the separated oil further confirmed the absence of emulsifier contamination in oil. More importantly, the Pickering emulsion could be reformed by fresh oil and the recycled aqueous phase after removing CO. The CO-responsive behavior of CAs was further analyzed with molecular dynamics simulation. This strategy effectively addresses some of the problems associated with other bio-based emulsifiers, such as difficulties in demulsification and potential contaminations in the oil phase, which has significant applications in pipeline transportation and biphasic catalysis.
对于需要临时稳定的乳液而言，破乳是必要的。然而，乳化剂的两亲性会给破乳带来挑战，并且它们在油相中的残留也会损害油品质量。在此，我们描述了一种由壳聚糖聚集体（CAs）稳定的CO 可切换Pickering乳液，其中乳化剂可以在水中回收再利用。在pH大于pK值（共轭酸的酸解离常数，例如pH 6.5）时，包括原油在内的各种油都可以被0.05 wt%的CAs乳化。CO₂引发的CAs与亲水性聚合物链（CCs）之间的可逆转变不仅促进了快速破乳（≤10分钟），还实现了乳化剂在水中的完全回收，油相中无残留。经过6个循环后分离出的油的界面张力与新鲜油的界面张力相当（50.2±1.0 mN/m）。对分离出的油进行元素分析进一步证实了油中不存在乳化剂污染。更重要的是，去除CO后，Pickering乳液可以用新鲜油和回收的水相重新形成。通过分子动力学模拟进一步分析了CAs的CO响应行为。该策略有效解决了与其他生物基乳化剂相关的一些问题，如破乳困难和油相中的潜在污染问题，在管道运输和双相催化方面具有重要应用。
