Liquid Crystal Self-Assembly and Organic–Inorganic Hybrid Material Design

Viruses offer promising applications in virotronics (virus-based technology) and as soft scaffolds for building intelligent (i.e. responsive) multicomponent materials. The Ff class of phages including M13 and fd phages have recently received high attention due to their high uniformity and monodisper...

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Bibliographic Details
Main Author: Moghimian, Pouya
Format: Others
Language:en
Published: 2017
Online Access:https://tuprints.ulb.tu-darmstadt.de/5954/13/PhD%20Thesis%20-%20Moghimian%2030.01.2017-2.pdf
Moghimian, Pouya <http://tuprints.ulb.tu-darmstadt.de/view/person/Moghimian=3APouya=3A=3A.html> (2017): Liquid Crystal Self-Assembly and Organic–Inorganic Hybrid Material Design.Darmstadt, Technische Universität, [Ph.D. Thesis]
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Summary:Viruses offer promising applications in virotronics (virus-based technology) and as soft scaffolds for building intelligent (i.e. responsive) multicomponent materials. The Ff class of phages including M13 and fd phages have recently received high attention due to their high uniformity and monodispersity. Phages have been used in virus-based applications owing to their low cost production, mild working temperature and pH conditions, chemical modifiability and ease of manipulation. In addition, they were found to exhibit liquid crystalline behavior in solutions; a property that made rod-like phages suitable material for self-assembly and soft matter physics. All of these features brought phages in the center of focus for the use in diverse applications such as semiconductors, chemical and biological sensing and piezoelectric nanogenerators. Spontaneous assembly of anisometric colloidal particles, such as rod-like M13 phages, in two-dimensions (2D) can be carried out via evaporation of the colloid-containing suspensions on solid substrates. Rod-like particles having a high aspect ratio (e.g. very long inoviruses) show liquid crystal (LC) behavior in suspensions and they can be treated as polymer chains composed of homogenous elastic material, where the persistence length characterizes the molecular stiffness. Therefore, suspensions containing M13 phages are considered to be ideal model systems for studying the properties of soft matter systems. Here, I designed an experiment in order to obtain a condition in which filamentous M13 phages have a high degree of alignment along a common axis on a solid substrate. One aim is to attain a fully covered surface with densely packed and highly oriented M13 phage particles. Moreover, the effect of substrate surface chemistry on the alignment and orientation of macromolecules was investigated. Our results suggest an approach that can be used to immobilize oriented viral arrays on amorphous carbon surface. A unique feature of our approach is that the aforementioned architectures can be obtained by applying phage solution on a surface without employing nanoparticle assembly methods such as dip coating or convective assembly. However, an ordered medium of liquid crystals often possesses a variety of defects and deformations, at which the director n(r) of the liquid crystal undergoes an abrupt change compared to the vicinity of the defect. Experimental research on these effects has been remained challenging and been barely performed on confined rod-like colloidal particles on structured surfaces. Therefore, I intend to investigate the local deformation of rod-like M13 phage particles resulting from confinement in an irregular stranded web of thin carbon film and compare them to the existing theories. I shift the focus from evaporative self-organization on rationally designed surfaces to that on a complex surface. The aim is to study the possibility of controlling the orientation of M13 phages in two-dimensional nematic films by choosing structured substrates. These rod-like molecules have the ability to mineralize a variety of inorganic materials. They can be used for the controlled growth of inorganic materials and for the production of hybrid structures. Owing to this property, phages are in the center of attention for the selected deposition and mineralization of inorganic substances. Here, I use M13 phages to mineralize zinc oxide nanoparticles from a deposition solution. This allowed us to construct nano-hybrid layered materials consisting of alternating organic (M13 phage) and inorganic (zinc oxide) layers (layer-by-layer) on a silicon substrate. Our aim is to achieve a homogeneous and uniform phage-assisted assembly of layered structures and to determine their microstructure, elemental composition and homogeneity. These hybrid structures have a potential for the use in biotechnology such as organic electronics.