Title：Design and Self-Assembly of Molecular-Mimicking Colloidal Particles
Speaker：Prof. Zhihong Nie
Department of Chemistry and Biochemistry
University of Maryland
Room：Supramolecular Building, Room A501
Keywords: self-assembly, nanoparticles, rods, molecular equivalent
Colloidal particles are of particular interest because of their broad applications, e.g., in coating, sensing, and photonic crystals. Assembly of colloidal particles into ordered architectures is essential for engineering new functional materials and devices. Moreover, colloidal particles can be used as model systems for studying the assembly or phase behavior of atoms and molecules. In the past decades, tremendous progress has been achieved in the design of colloidal particles that mimic conventional molecules, as well as in the exploitation of their assembly behaviors. However, unmet challenges still remain at this frontier.
In this talk, I will present our efforts on the synthesis and self-assembly of molecular-mimicking colloidal particles. First, I will present the synthesis of monodisperse bent rods by controlled perturbation of emulsion-templated growth. The bending angle of the rods can be tuned in a range of 0−50° by varying the strength of perturbation. The length of each arm of the bent rods can be individually controlled by adjusting the reaction time. The bent silica rods resemble banana-shaped liquid-crystal molecules and assemble into arrange of classic liquid-crystal phases. Second, I will present the design and self-assembly of supracolloidal molecules with defined valences and surface patches. The supracolloidal molecules are fabricated by assembling binary inorganic nanoparticles isotropically grafted with block copolymers. The valences and surface patches (i.e., local surface chemistry) of the supracolloids can be precisely tuned by controlling the polymer ligands on nanoparticle surfaces. As an example, we demonstrated the preparation of nanoscale amphiphilic supracollods with defined number and position of hydrophilic and hydrophobic patches. It is remarkable that such supracollods can further assemble into hierarchical structures via directional interactions.