One-dimensional hybrid nanomaterials based on cylindrical polymer brushes [Elektronische Ressource] / vorgelegt von Jiayin Yuan

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One-dimensional Hybrid Nanomaterials Based on Cylindrical Polymer Brushes DISSERTATION zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) im Fach Chemie der Fakultät für Biologie, Chemie und Geowissenschaften der Universität Bayreuth vorgelegt von Jiayin Yuan Geboren in Anhui / China Bayreuth, 2009 Die vorliegende Arbeit wurde in der Zeit von März 2005 bis September 2008 in Bayreuth am Lehrstuhl Makromolekulare Chemie II unter Betreuung von Herrn Prof. Dr. Axel H. E. Müller angefertigt. Vollständiger Abdruck der von Fakultät für Biologie, Chemie und Geowissenschaften der Universität Bayreuth genehmigten Dissertation zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. Nat.). Dissertation eingereicht am: 12.01.2009 Zulassung durch die Promotionskommission: 14.01.2009 Wissenschaftliches Kolloquium: 02.04.2009 Amtierender Dekan: Prof. Dr. Axel H. E. Müller Prüfungsausschuss: Prof. Dr. A. H. E. Müller (Erstgutachter) Prof. Dr. M. Ballauff (Zweitgutachter) Prof.. Dr. K. Seifert (Vorsitzender) Prof. Dr. J. Breu To my wife Yan You never know what you can do till you try. Table of contents Table of contents I Introduction 1 1.1 Cylindrical polymer brushes 1 1.1.1 Synthesis of cylindrical polymer brushes 2 1.1.1.1 Grafting through 3 1.1.1.
Publié le : jeudi 1 janvier 2009
Lecture(s) : 127
Source : OPUS.UB.UNI-BAYREUTH.DE/VOLLTEXTE/2009/551/PDF/DISS.PDF
Nombre de pages : 183
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One-dimensional Hybrid Nanomaterials
Based on Cylindrical Polymer Brushes



DISSERTATION

zur Erlangung des akademischen Grades eines
Doktors der Naturwissenschaften (Dr. rer. nat.)
im Fach Chemie der Fakultät für Biologie, Chemie und
Geowissenschaften der Universität Bayreuth

vorgelegt von
Jiayin Yuan
Geboren in Anhui / China

Bayreuth, 2009 Die vorliegende Arbeit wurde in der Zeit von März 2005 bis September 2008 in Bayreuth
am Lehrstuhl Makromolekulare Chemie II unter Betreuung von Herrn Prof. Dr. Axel H. E.
Müller angefertigt.


Vollständiger Abdruck der von Fakultät für Biologie, Chemie und Geowissenschaften der
Universität Bayreuth genehmigten Dissertation zur Erlangung des akademischen Grades
eines Doktors der Naturwissenschaften (Dr. rer. Nat.).

Dissertation eingereicht am: 12.01.2009
Zulassung durch die Promotionskommission: 14.01.2009
Wissenschaftliches Kolloquium: 02.04.2009

Amtierender Dekan: Prof. Dr. Axel H. E. Müller

Prüfungsausschuss:
Prof. Dr. A. H. E. Müller (Erstgutachter)
Prof. Dr. M. Ballauff (Zweitgutachter)
Prof.. Dr. K. Seifert (Vorsitzender)
Prof. Dr. J. Breu



To my wife Yan











You never know what you can do till you try. Table of contents
Table of contents

I Introduction 1
1.1 Cylindrical polymer brushes 1
1.1.1 Synthesis of cylindrical polymer brushes 2
1.1.1.1 Grafting through 3
1.1.1.2 onto 4
1.1.1.3 Grafting from 5
1.1.2 Properties of cylindrical polymer brushes 7
1.1.2.1 Solution proertis 7
1.1.2.2 Properties in the bulk 9
1.1.2.3 Cylindrical polymer brushes in thin-films on different substrates 9
1.1.3 Structures of cylindrical polymer brushes 11
1.1.3.1 Core-shell and core-shell-corona cylindrical polymer brushes 12
1.1.3.2 Statistical and Janus-type cylindrical polymer brushes 14
1.1.3.3 Hetero-grafted block-type cylindrical polym 15
1.1.3.4 Gradient cylindrical polymer brushes 16
1.1.3.5 Macrocyclic polymer brushes 18
1.1.3.6 Superstructures from cylindrical polymer brushes 19
1.1.4 Hybrid nanostructures templated by cylindrical polymer brushes 20
1.2 One-dimensional hybrid organic-inorganic nanostructures 22
1.2.1 1-D hybrid organic-inorganic nanostructures 22
1.2.2 Template-directd synthesi 23
1.2.2.1 Self-assembled molecular structures 23
1.2.2.2 Naturl 1-D structres 26
1.2.2.3 Channels in porous materials 27
1.2.3 Electrospinning techniques 28
1.2.4 1-D hybrids prepared by other methods 30
1.3 Objective of this thesis 31
1.4 References 32

Table of contents
II Overview of the thesis 41
2.1 Water-soluble organo-silica hybrid nanowires 42
2.2 Cadmium selenide nanowires within core-shell CPBs: synthesis,
characterization and the double-loading process 45
2.3 Template-directed synthesis of titania hybrid nanowires within core-shell
cylindrical polymer brushes 48
2.4 Room-temperature growth of uniform tellurium nanorods and the assembly
of tellurium or Fe O nanoparticles on the nanorods 52 3 4
2.5 Alignment of tellurium nanorods via a magnetization-alignment-
demagnetization (“MAD”) process assisted by an external magnetic field 54
2.6 Individual contributions to joint publications 57
2.7 References 60

III Water-soluble organo-silica hybrid nanowires 61
3.1 Introduction 62
3.2 Experimental section 63
3.3 Results and discussion 65
3.4 Conclusions 72
3.5 References 73
3.6 Supporting information 75

IV Cadmium selenide nanowires within core-shell CPBs: synthesis,
characterization and the double-loading process 77
4.1 Introduction 78
4.2 Experimental section 80
4.3 Results and discussion 82
4.4 Conclusions 92
4.5 References 93

V Template-directed synthesis of titania hybrid nanowires within
core-shell cylindrical polymer brushes 97
5.1 Introduction 98
Table of contents
5.2 Experimental section 99
5.2.1 Synthesis of titania-CPB hybrid nanowires and inorganic titania nanowires 99
5.2.2 Characterization methods 100
5.3 Results and discussion 101
5.4 Conclusions 111
5.5 References 112

VI Room-temperature growth of uniform tellurium nanorods and the
assembly of tellurium or Fe O nanoparticles on the nanorods 115 3 4
6.1 Introduction 116
6.2 Experimental section 118
6.3 Results and discussion 119
6.4 Conclusions 126
6.5 References 127
6.6 Supporting information 129

VII Alignment of tellurium nanorods via a magnetization-alignment-
demagnetization (“MAD”) process assisted by an external magnetic
field 135
7.1 Introduction 136
7.2 Experimental section 138
7.3 Results and discussion 140
7.4 Conclusions 149
7.5 References 150
7.6 Supporting information 152

VIII Summary / Zusammenfassung 159

IX List of publications 163

Chapter 1   Introduction 
Chapter 1 Introduction

The development of novel materials with new properties and improved performance is a
continually expanding research area, which covers subjects ranging from chemistry, physics,
biology, to material science. The largest activity in this field currently is the generation and the
study of nanomaterials where the constructing units have at least one dimension between 1 and
100 nm. The interest in such structures mainly originates from the fact that novel properties are
only acquired at this dimension scale, and equally important, that these properties change with
their size or shape, which is not a result of scaling factors.
Among various reported structures, one-dimensional (1-D) materials such as wires, rods,
tubes, etc., are expected to play an important role as both building blocks, interconnects, and
functional units in fabricating nanoscale devices.
Exemplarily, polymer-inorganic 1-D hybrid nanomaterials are of considerable interest because
1, 2of their wide-spread applications in fields like electronics, optics, catalysis, and sensors. They
combine the intrinsic properties of 1-D inorganic nanostructures with very desirable
characteristics of polymers, for instance, processability, dispersibility and solubility. The recent
advances in “living” / controlled radical polymerization (CRP) techniques have provided plenty
of opportunities to design and construct numerous functional polymers with rising complexity
concerning their structures and components. This paths the way to meet the increasing
requirements in the field of material science. In this thesis, different types of cylindrical polymer
brushes with well-defined structure and controlled dimensions were prepared via the combination
of anionic polymerization and atom transfer radical poylmerization; these polymers were further
used as templates and supporting agent for the controlled fabrication of 1-D hybrid
nanomaterials.

1.1 Cylindrical polymer brushes
Cylindrical polymer brushes (CPBs), i.e. “molecular bottlebrushes”, which possess linear side
chains or high-generation dendritic side groups densely grafted from a linear main chain (ideally
every monomer unit of the main chain carries one side chain), have attracted considerable
3attention over the past decade. These polymeric cylinders are architecturally interesting for both
1Chapter 1   Introduction 
experimental and theoretical chemists, owing to their unique properties in solution, bulk and thin
films, especially the possibility of forming extended chain conformations based on the
intramolecular excluded-volume interactions between densely grafted side chains. Moreover,
their hyperbranched structure leads to very compact molecular dimensions in comparison with
the corresponding linear polymers with a comparable molecular weight.
In the last two decades, advances in “living” / controlled radical polymerization (CRP)
4techniques like atom transfer radical polymerization (ATRP) , reversible addition-fragmentation
5 6chain transfer (RAFT), and nitroxide-mediated radical polymerization (NMP) have greatly
facilitated the design, preparation and functionalization of CPBs. These techniques act as
powerful tools and permit an unprecedented opportunity in the control and construction of
macromolecules with a variety of monomers under mild conditions. Accordingly, many CPBs
with diverse new architectures have been synthesized and studied to understand their properties.
Furthermore, due to their anisotropic nature CPBs have successfully been employed as “soft” 1-
7, 8D templates to direct the synthesis of inorganic 1-D nanostructures.

1.1.1 Synthesis of CPBs
9-11 12-14 15-18 Three basic methods, the “grafting through” , “grafting onto” , and “grafting from”
strategies, have been mainly used in the synthesis of CPBs. These brushes possess enough linear
or dendritic side chains covalently bonded to a linear backbone (i.e. main chain), and stretch it to
19achieve the cylindrical shape. In addition, noncovalent interactions, such as hydrogen bonding,
20 21ionic interactions, and coordination bonding have also been reported to attach side-groups
onto linear polymer chains. Moreover, such structures can be prepared through the self-assembly
of block copolymers. For example, core-crosslinked cylindrical micelles of block copolymers in
22solution, the crosslinking of cylindrical microdomains of microphase-separated block
23, 24copolymers in the bulk, and core-shell wormlike polymeric cylinders with crystalline or
25semicrystalline cores have been reported. In these cases, the side chains were covalently bound
to a linear fixed microdomain instead of a linear polymer backbone. (Scheme 1-1)
2

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