Solvent switching and purification of colloidal nanoparticles through water/oil Interfaces within a density gradient
density gradient, water/oil interface, solvent switching, purification
Traditional post-treatment of colloidal nanoparticles (NPs) usually involves repeated centrifugation–wash–sonication processes to separate NPs from the original synthetic environment; however, suchseparation processes have either high energy cost or low efficiency and tend to cause aggregation. Here we show a general and scalable colloid post-processing technique based on density gradient centrifugation through water/oil interfaces. Such a one-step technique can switch the solvent in a colloid at almost any concentration without aggregation, and meanwhile purify colloidal nanoparticles by separating them from by-products and environmental impurities. Droplet sedimentation was shown to be the mechanism of this one-step concentration/purification process, and mathematical modeling was established to quantify the accumulation and sedimentation velocities of different NPs.
Tsinghua University Press
Yun Kuang,Sha Song,Xiaofei Liu,Minglin Li,Zhao Cai,Liang Luo,Xiaoming Sun, Solvent switching and purification of colloidal nanoparticles through water/oil Interfaces within a density gradient. NanoRes.2014, 7(11): 1670–1679