Researchers at  Pacific Northwest National Laboratory used Hummingbird TEM liquid cell mixing holder to observe the dynamics of nanoparticle self-assembly when mixed in two different solutions. The work published in the Journal of Physical Chemistry C shows self-assembly of gold nanoparticles (NPs) into superlattices when mixed in solutions containing water and ionic liquid (IL). They observed that the IL played a dual role in the self-assembly process. At intermediate concentration, the IL forms a stabilizing surfactant and forms a well-defined separation between the particles. At high concentration, IL accumulates and there is no well-defined separation, causing the particles to coalesce.

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Reference:

Lili Liu, Duo Song, Biao Jin, Michael A. Sinnwell, Jun Liu, James J. De Yoreo, and Maria L. Sushko. Role of the Solvent–Surfactant Duality of Ionic Liquids. in Directing Two-Dimensional Particle Assembly. The Journal of Physical Chemistry C (2020).