Riedl J C, Sarkar M, Fiuza T, Cousin F, Depeyrot J, Dubois E, Mériguet G, Perzynski R, Peyre V
Sorbonne Université, CNRS, Laboratoire PHENIX, 4 place Jussieu, case 51, 75005 Paris, France.
Sorbonne Université, CNRS, Laboratoire PHENIX, 4 place Jussieu, case 51, 75005 Paris, France; Inst. de Fisica, Complex Fluid Group, Universidade de Brasília, Brasília, Brazil.
J Colloid Interface Sci. 2022 Feb;607(Pt 1):584-594. doi: 10.1016/j.jcis.2021.08.017. Epub 2021 Aug 19.
Some of the most promising fields of application of ionic liquid-based colloids imply elevated temperatures. Their careful design and analysis is therefore essential. We assume that tuning the structure of the nanoparticle-ionic liquid interface through its composition can ensure colloidal stability for a wide temperature range, from room temperature up to 200 °C.
The system under study consists of iron oxide nanoparticles (NPs) dispersed in ethylmethylimidazolium bistriflimide (EMIM TFSI). The key parameters of the solid-liquid interface, tuned at room temperature, are the surface charge density and the nature of the counterions. The thermal stability of these nanoparticle dispersions is then analysed on the short and long term up to 200 °C. A multiscale analysis is performed combining dynamic light scattering (DLS), small angle X-ray/neutron scattering (SAXS/SANS) and thermogravimetric analysis (TGA).
Following the proposed approach with a careful choice of the species at the solid-liquid interface, ionic liquid-based colloidal dispersions of iron oxide NPs in EMIM TFSI stable over years at room temperature can be obtained, also stable at least over days up to 200 °C and NPs concentrations up to 12 vol% (≈30 wt%) thanks to few near-surface ionic layers.
基于离子液体的胶体的一些最有前景的应用领域涉及高温。因此，对它们进行精心设计和分析至关重要。我们假设通过纳米颗粒 - 离子液体界面的组成来调整其结构，可以确保在从室温到200°C的宽温度范围内的胶体稳定性。
所研究的系统由分散在双三氟甲磺酰亚胺乙基甲基咪唑鎓（EMIM TFSI）中的氧化铁纳米颗粒（NPs）组成。在室温下调整的固 - 液界面的关键参数是表面电荷密度和抗衡离子的性质。然后在高达200°C的短时间和长时间内分析这些纳米颗粒分散体的热稳定性。结合动态光散射（DLS）、小角X射线/中子散射（SAXS/SANS）和热重分析（TGA）进行多尺度分析。
按照所提出的方法，仔细选择固 - 液界面处的物种，可以获得在室温下多年稳定的EMIM TFSI中氧化铁NPs的基于离子液体的胶体分散体，由于少量近表面离子层，在高达200°C和高达12体积％（≈30重量％）的NPs浓度下至少在数天内也是稳定的。
