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Structure and properties of nanostructures from polyelectrolytes and porphyrins [Elektronische Ressource] : self-Assembly in aqueous solution / Christian Ruthard

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Structure and Properties of Nanostructures from Polyelectrolytes and Porphyrins: Self-Assembly in Aqueous Solution Dissertation zur Erlangung des Grades „Doktor der Naturwissenschaften” im Promotionsfach Chemie am Fachbereich Chemie, Pharmazie und Geowissenschaften der Johannes Gutenberg-Universität in Mainz Christian Ruthard geboren in Mainz Mainz, 2010 ii D77 (Dissertation Universität Mainz) iii iv Für Annika v vi Abstract ABSTRACT In this work self-assembling model systems in aqueous solution were studied. The systems contained charged polymers, polyelectrolytes, that were combined with oppositely charged counterions to build up supramolecular structures. With imaging, scattering and spectroscopic techniques it was investigated how the structure of building units influences the structure of their assemblies. Polyelectrolytes with different chemical structure, molecular weight and morphology were investigated. In addition to linear polyelectrolytes, semi-flexible cylindrical bottle-brush polymers that possess a defined cross-section and a relatively high persistence along the backbone were studied. The polyelectrolytes were combined with structural organic counterions having charge numbers one to four.

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Published 01 January 2010
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Structure and Properties of Nanostructures from
Polyelectrolytes and Porphyrins:
Self-Assembly in Aqueous Solution




Dissertation
zur Erlangung des Grades
„Doktor der Naturwissenschaften”
im Promotionsfach Chemie



am Fachbereich Chemie, Pharmazie und Geowissenschaften
der Johannes Gutenberg-Universität
in Mainz





Christian Ruthard
geboren in Mainz




Mainz, 2010



























ii D77 (Dissertation Universität Mainz)




iii


iv


Für Annika

v

vi Abstract
ABSTRACT
In this work self-assembling model systems in aqueous solution were studied. The
systems contained charged polymers, polyelectrolytes, that were combined with
oppositely charged counterions to build up supramolecular structures. With imaging,
scattering and spectroscopic techniques it was investigated how the structure of building
units influences the structure of their assemblies. Polyelectrolytes with different
chemical structure, molecular weight and morphology were investigated. In addition to
linear polyelectrolytes, semi-flexible cylindrical bottle-brush polymers that possess a
defined cross-section and a relatively high persistence along the backbone were studied.
The polyelectrolytes were combined with structural organic counterions having charge
numbers one to four. Especially the self-assembly of polyelectrolytes with different
tetravalent water-soluble porphyrins was studied. Porphyrins have a rigid aromatic
structure that has a structural effect on their self-assembly behavior and through which
porphyrins are capable of self-aggregation via π-π interaction. The main focus of the
thesis is the self-assembly of cylindrical bottle-brush polyelectrolytes with tetravalent
porphyrins. It was shown that the addition of porphyrins to oppositely charged brush
molecules induces a hierarchical formation of stable nanoscale brush-porphyrin
networks. The networks can be disconnected by addition of salt and single porphyrin-
decorated cylindrical brush polymers are obtained. These two new morphologies, brush-
porphyrin networks and porphyrin-decorated brush polymers, may have potential as
functional materials with interesting mechanical and optical properties.
vii Zusammenfassung
ZUSAMMENFASSUNG
In dieser Arbeit wurden selbst-organisierende Modellsysteme in wässriger Lösung
untersucht. Geladene Polymere, sogenannte Polyelektrolyte, wurden mit
entgegengesetzt geladenen Ionen in Verbindung gebracht, um supramolekulare
Strukturen aufzubauen. Mit abbildenden Methoden, Spektroskopie und Streumethoden
wurde untersucht, inwiefern die Struktur der Bausteine die Struktur der
selbstorganisierten Systeme beeinflusst. Hierbei wurden Polyelektrolyte mit
unterschiedlicher chemischer Struktur, Molekulargewicht und Architektur verwendet.
Zusätzlich zu linearen Polyelektrolyten wurden semiflexible zylindrische
Bürstenpolymere mit definiertem Durchmesser und relativ hoher Hauptkettenpersistenz
untersucht. Den Polyelektrolyten wurden strukturelle organische Gegenionen mit der
Ladungszahl eins bis vier zugegeben. Insbesondere die Selbstorganisation von
Polyelektrolyten mit verschiedenen tetravalenten und wasserlöslichen Porphyrinen
wurde untersucht. Porphyrine haben eine steife aromatische Struktur, die einen
strukturellen Effekt auf ihr Verhalten bei der Selbstorganisation hat und durch diese
Porphyrine die Möglichkeit besitzen durch π-π Wechselwirkungen zu aggregieren. Der
Hauptfokus dieser Arbeit liegt in der Selbstorganisation von zylindrischen
Bürstenpolyelektrolyten mit tetravalenten Porphyrinen. Es konnte gezeigt werden, dass
die Zugabe von Porphyrinen zu entgegengesetzt geladenen Bürstenpolymeren zu einem
hierarchischen Aufbau von stabilen, nanoskaligen Bürsten-Porphyrin Netzwerken führt.
Die Netzwerkverbindungen können durch Zugabe von Salz gelöst werden und einzelne
Porphyrin-beladene, zylindrische Bürstenpolymere werden erhalten. Diese beiden neuen
Strukturen, Bürsten-Porphyrin Netzwerke und Porphyrin-beladene Bürstenpolymere,
haben Potential als funktionelle Materialien mit interessanten mechanischen und
optischen Eigenschaften.

viii Table of Contents
TABLE OF CONTENTS
Page
ABSTRACT ................................................................................................................... vii
ZUSAMMENFASSUNG .............................................................................................. viii
CHAPTER
1 INTRODUCTION ................................................................................................... 1
2 THEORY & METHODS ......................................................................................... 3
2.1 Methods to Study Polyelectrolyte Complexation ......................................... 3
2.1.1 Light Scattering ................................................................................. 3
2.1.2 Atomic Force Microscopy ................................................................ 9
2.2 Porphyrins ................................................................................................... 10
2.2.1 The Absorption Spectrum of Porphyrins ........................................ 10
2.2.2 Porphyrin Aggregation .................................................................... 13
3 COMPLEXATION OF PSS BRUSHES WITH NONAROMATIC STRUCTURAL
COUNTERIONS 17
4 SELF-AGGREGATION OF WATER-SOLUBLE PORPHYRINS....................... 27
4.1 Cationic Porphyrin: TAPP .......................................................................... 27
4.2 Anionic Porphyrin: TPPS ........................................................................... 32
5 SELF-ASSEMBLY OF PSS BRUSHES WITH THE CATIONIC PORPHYRIN
TAPP ...................................................................................................................... 41
5.1 Brush-TAPP Complexes in Salt-Free Water ............................................... 41
5.1.1 Spectroscopic Properties of Complexes from NaPSS Brush and
TAPP ............................................................................................... 42
5.1.2 Imaging of Complexes from NaPSS Brush and TAPP ................... 56
5.1.3 Small-Angle Neutron Scattering of Brush-Porphyrin Aggregates .. 64
5.1.4 Size of Brush-Porphyrin Aggregates by Light Scattering ............... 66
5.1.5 Influence of Sample Preparation Protocol ...................................... 71
ix Table of Contents
5.2 Brush-TAPP Complexes in Salt Solution ................................................... 74
5.3 Brush-TAPP Complexes in the Presence of DMSO ................................... 77
6 INFLUENCE OF POLYELECTROLYTE AND PORPHYRIN STRUCTURE ON
PSS-PORPHYRIN COMPLEXATION ................................................................ 87
6.1 Influence of Polyelectrolyte Structure and Size: Linear PSS ..................... 87
6.2 Influence of Porphyrin Structure 95
7 NETWORK FORMATION OF PVP BRUSHES WITH THE ANIONIC
PORPHYRIN TPPS: PH-DEPENDENCE ......................................................... 103
7.1 Complexation of PVP with TPPS at pH = 7 ............................................. 105
7.2 Complexation of PVP with TPPS at pH < 4 .............................................. 113
8 COMPLEXATION OF AGGRECAN WITH TAPP ........................................... 139
9 SUMMARY & CONCLUSION .......................................................................... 149
APPENDICES
A MATERIALS ...................................................................................................... 151
B METHODS.......................................................................................................... 168
LIST OF ABBREVIATIONS ...................................................................................... 175
BIBLIOGRAPHY ....................................................................................................... 178
ACKNOWLEDGMENTS ........................................................................................... 190

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