Direct imaging of self-assembly behaviors of colloids: from the microscale plates to the nanoscale cubes

Microscale and nanoscale colloidal particle self-assembly is widely studied to establish the design rules towards ordered structures and used as atomic model systems for phase transition studies such as crystallization and growth. The well-established synthetic library enables the synthesis of colloidal particles with controllable size, morphology, and surface chemistry, which dictates their interactions for self-assembly. This dissertation focuses on studying a promising yet underexplored colloidal building blocks: anisometric colloids and developing direct imaging tool of liquid-phase transmission electron microscopy (TEM) to visualize and quantify the less-explored nanoparticle self-assembly dynamics in solution. I begin by engineering highly directional interactions of micron-sized silver plates through colloidal synthesis and surface functionalization, to induce their co-assembly with patchy spheres into complex, 2D architectures. Utilizing a combination of direct optical microscopy imaging, theoretical modeling, and automated single particle tracking, I further demonstrate an unconventional crystallization pathway into 3D hierarchical lattices from polydisperse colloids. Then I focus on a foundationally new imaging tool known as liquid-phase TEM for in-situ imaging of otherwise inaccessible solution-phase nanoparticle self-assembly dynamics at nanometer resolution. I substantially advanced this technique and revealed, for the first time, the nanoparticle assembly dynamics such as a layer-by-layer growth process into flat superlattices. This dissertation concludes by highlighting new opportunities from this technical improvement in navigating colloidal interactions to engineer the conformation, phase behaviors and collective dynamics of colloids on the nanometer length scale. The generalized interaction engineering strategy from my research can serve as a general guideline for the design and fabrication of functional colloidal materials from the bottom-up.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Luo, Binbin

Contributors dc:contributor

• Chen, Qian
• Braun, Paul V.
• Cheng, Jianjun
• Zuo, Jian-Min
• Schroeder, Charles M.

• Nanoparticles
• self-assembly
• colloids
• liquid-phase TEM
• dynamics

Statement dc:rights

• Copyright 2020 Binbin Luo

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/108278

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/108278