title: Linker-Mediated Self-Assembly Dynamics of Charged Nanoparticles.
abstract: Using in situ liquid cell transmission electron microscopy (TEM), we visualized a stepwise self-assembly of surfactant-coated and hydrated gold nanoparticles (NPs) into linear chains or branched networks. The NP binding is facilitated by linker molecules, ethylenediammonium, which form hydrogen bonds with surfactant molecules of neighboring NPs. The observed spacing between bound neighboring NPs, ∼15 Å, matches the combined length of two surfactants and one linker molecule. Molecular dynamics simulations reveal that for lower concentrations of linkers, NPs with charged surfactants cannot be fully neutralized by strongly binding divalent linkers, so that NPs carry higher effective charges and tend to form chains, due to poor screening. The highly polar NP surfaces polarize and partly immobilize nearby water molecules, which promotes NPs binding. The presented experimental and theoretical approach allows for detail observation and explanation of self-assembly processes in colloidal nanosystems.
authors: Department of Physics, National University of Singapore , 117551, Singapore.|Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 117546, Singapore.|Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 117543, Singapore.|NanoCore, National University of Singapore , 117576, Singapore.
authors: Guanhua
authors: G
authors: Lin
authors: Department of Physics, National University of Singapore , 117551, Singapore.|Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 117546, Singapore.|Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 117543, Singapore.
authors: See Wee
authors: SW
authors: Chee
authors: Sanoj
authors: S
authors: Raj
authors: Petr
authors: P
authors: Král
authors: Department of Physics, National University of Singapore , 117551, Singapore.|Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore , 117546, Singapore.|Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore , 117543, Singapore.|NanoCore, National University of Singapore , 117576, Singapore.
authors: Utkur
authors: U
authors: Mirsaidov
keywords: in situ TEM; nanoparticle; nanoparticle chains; self-assembly