Mamusa Marianna, Sirieix-Plénet Juliette, Perzynski Régine, Cousin Fabrice, Dubois Emmanuelle, Peyre Véronique
Université Pierre et Marie Curie - Paris 6 - PHENIX UMR CNRS 8234, Paris, France.
Faraday Discuss. 2015;181:193-209. doi: 10.1039/c5fd00019j.
Maghemite (γ-Fe2O3) nanoparticles (NPs) can be successfully dispersed in a protic ionic liquid, ethylammonium nitrate (EAN), by transfer from aqueous dispersions into EAN. As the aqueous systems are well controlled, several parameters can be tuned. Their crucial role towards the interparticle potential and the structure of the dispersions is evidenced: (i) the size of the NPs tunes the interparticle attraction monitoring dispersions to be either monophasic or gas-liquid-like phase separated; (ii) the nature of the initial counterion in water (here sodium, lithium or ethylammonium) and the amount of added water (<20 vol%) modulate the interparticle repulsion. Very concentrated dispersions with a volume fraction of around 25% are obtained thanks to the gas-liquid-like phase separations. Such conclusions are derived from a fine structural and dynamical study of the dispersions on a large range of spatial scales by coupling several techniques: chemical analyses, optical microscopy, dynamic light scattering, magneto-optic birefringence and small angle scattering.
通过从水分散体转移至硝酸乙铵（EAN）中，磁赤铁矿（γ-Fe2O3）纳米颗粒（NPs）能够成功分散于质子离子液体硝酸乙铵（EAN）中。由于水相体系得到了很好的控制，因此可以调节几个参数。这些参数对颗粒间电势和分散体结构的关键作用得到了证明：（i）纳米颗粒的尺寸调节颗粒间吸引力，从而监测分散体是单相的还是气液状相分离的；（ii）水中初始抗衡离子的性质（这里是钠、锂或乙铵）以及添加水的量（<20体积%）调节颗粒间排斥力。由于气液状相分离，获得了体积分数约为25%的非常浓缩的分散体。这些结论源自通过结合多种技术对分散体在大范围空间尺度上进行的精细结构和动力学研究：化学分析、光学显微镜、动态光散射、磁光双折射和小角散射。
