Authors:	Guo, Yinzhou
Title:	Guiding the assembly of nanoparticles with polymers
Online publication date:	8-Apr-2021
Year of first publication:	2021
Language:	english
Abstract:	In the design of new materials, not only different chemical composition but also different structures lead to different properties. At the molecular level, different atoms can be assembled in a controlled manner to form molecules with varying structures by changing the composition of the atoms and the type of bonds present between them. This results in different molecules having various properties. At the colloid level, the assembly of colloidal building blocks could potentially have a similar variety. However, until now, we have a limited number of methods to control the self-assembly of the colloidal particles, especially to control the type of “bonds” controlling the orientation of the colloids in the assembled structure. Consequently, the ability to form different supra-colloidal structures with a rational design remains an open challenge. In order to develop a methodology to control the formation of more complex supracolloidal structures, diverging from the common close-packed structures, there is a need to introduce directionality in the assembly process. One of the keys to successfully do so is to introduce directionality in the structure of the nanoparticle. Among the methods that can create this directionality is the use of patchy polymer nanoparticles or anisotropic metal particles. The first target for the design of patchy nanoparticles with distinct shapes was binary particles of gold with patches of cerium oxide. Gold nanosphere, gold nanorod, and gold nanotriangle were used as the template for the growth of the cerium oxide domains. Then, the resulting nanoparticles were used to catalyze model reactions in suspensions. The gold nanoparticles covered with patches of cerium oxide outperformed the fully covered and the naked nanoparticles in terms of catalytic efficiency. Finally, the most efficient heteronanostructures were successfully embedded in nanofibrous membranes by colloidal electrospinning and used in water remediation experiments in a flow-through reactor (Section 4.1). A second target for the introduction of directionality in the formation of supracolloidal structures is the formation of 1D colloidal chains made by the assembly of polymer functionalized nanoparticles in suspension (Sections 4.2 and 4.3). By controlling the coverage of the nanoparticles with the polymer chains (Section 4.2) and the quality of the solvent (Section 4.3) it is possible to form different supracolloidal structures went complementary nanoparticles are combined. The shape of the core and the interaction between the polymer patches play an essential role in the formation of the colloidal chains. The formation of directional assemblies can be observed both with directional building blocks (Section 4.2) or isotropic building blocks (section 4.3). The formation of directional chains or non-directional close-packed aggregates can be controlled by changing the condition, such as light and solvent quality. Furthermore, the same principles can also be used for the formation of 2D structures by confining the assembly at an interface. 2D colloidal monolayer film also can be prepared by patchy polymer-metal anisotropic nanoparticles via the Langmuir−Blodgett technique (Section 4.4). This work clearly demonstrates how the formation of supracolloidal assemblies can be used to prepare functional materials. Furthermore, this work provides design rules to generate complex supracolloidal structures by controlling the interaction between the building blocks.
DDC:	540 Chemie 540 Chemistry and allied sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-5728
URN:	urn:nbn:de:hebis:77-openscience-72132fee-2cc1-432a-a17c-7baf91ec31074
Version:	Original work
Publication type:	Dissertation
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Extent:	VI, 154, Illustrationen, Diagramme
Appears in collections:	JGU-Publikationen