Self-assembly of cross-linked polymer micelles into complex higher-order aggregates [Elektronische Ressource] / von Niels ten Brummelhuis

Niels Ten Brummelhuis

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• Publié par: universitat_potsdam
• Publié le: 01 janvier 2011
• Nombre de lectures: 34
• Poids de l'ouvrage: 10 Mo

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Self-assembly of cross-linked polymer micelles into higher-order aggregates


Self-assembly of
cross-linked polymer micelles into
complex higher-order aggregates










Niels ten Brummelhuis
1














































Published online at the
Institutional Repository of the University of Potsdam:
URL http://opus.kobv.de/ubp/volltexte/2011/5232/
URN urn:nbn:de:kobv:517-opus-52320
http://nbn-resolving.org/urn:nbn:de:kobv:517-opus-52320 Aus dem Max-Planck-Institut für Kolloid- und Grenzflächenforschung Self-assembly of cross-linked polymer micelles into higher-order aggregates
Abteilung für Kolloidchemie

Self-assembly of
cross-linked polymer micelles into
complex higher-order aggregates

Dissertation

zur Erlangung des akademischen Grades
Doktor der Naturwissenschaften
(Dr. rer. nat.)
in der Wissenschaftsdisziplin „Polymer- und Kolloidchemie“

eingereicht an der
Mathematisch-Naturwissenschaftlichen Fakultät
der Universität Potsdam


von
Niels ten Brummelhuis
geboren am 14.10.1985 in Heerenveen, die Niederlande

Potsdam, Januar 2011
3
Die vorliegende Arbeit entstand in der Zeit von Dezember 2008 bis Januar 2011 am Max-Planck-
Institut für Kolloid- und Grenzflächenforschung in Potsdam-Golm unter der Betreuung von
Prof. Dr. Markus Antonietti und Dr. habil. Helmut Schlaad.
4 Self-assembly of cross-linked polymer micelles into complex higher-order aggregates
Table of contents
Chapter 1 : Introduction 7
Chapter 2 : Background 9
2.1 Introduction 9
2.2 Morphologies 9
2.2.1 Block copolymer morphologies 10
2.3 Stimuli responsive polymers 11
2.3.1 Polyions 12
2.3.2 Thermoresponsive polymers 12
2.3.3 Light responsive polymers 15
2.4 C3Ms 15
2.5 Janus structures 17
2.6 The biotin streptavidin binding motive 18
2.7 Polymerization techniques
2.7.1 Anionic polymerization
2.7.2 Living cationic (ring-opening) polymerization 20
2.7.3 Controlled radical polymerizations 21
Chapter 3 : Polyoxazoline-based core cross-linked micelles 27
3.1 Simultaneous functionalization and core cross-linking
3.1.1 Introduction 27
3.1.2 Results and discussion 28
3.1.3 Conclusion 34
3.2 pH and thermoresponsive behavior of core cross-linked micelles 35
3.2.1 Introduction 35
3.2.2 Results and discussion 35
3.2.3 Conclusion 39
Chapter 4 : Core cross-linked complex coacervate core micelles and their aggregation behavior 41
4.1 Introduction 41
4.2 Polymer synthesis 43
4.3 C3JMs and C5JMs 50
4.3.1 Introduction 50
4.3.2 C3JMs 50
4.3.3 Corona structure 54
4.3.4 C5Ms 61
4.3.5 Higher-order aggregates 65
4.3.6 Higher-order aggregates through the interaction with nanoparticles 68
4.3.7 C5Ms as charge bearing building blocks for complex C3M structures 75
4.3.8 Conclusion 78
4.4 Inducing a Janus character by external stimuli 80
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4.4.1 Introduction 80
4.4.2 C3Ms 80
4.4.3 Cross-linked structures 82
4.4.4 Cross-linking of other C3M systems at higher temperature 89
4.4.5 Conclusion 90
Chapter 5 : Asymmetry from a symmetric protein template 91
5.1 Introduction 91
5.2 Polymer synthesis 92
5.3 Polymer-protein complexes 96
5.3.1 Janus complexes
5.3.2 Cross-linking 100
5.4 Conclusion 101
Chapter 6 : Summary and outlook3
Appendix 107
A.1 References 107
A.2 List of abbreviations 111
A.3 General materials and methods3
A.3.1 Chemicals 113
A.3.2 Characterization methods4
A.4 Appendix to Chapter 37
A.4.1 Synthesis 117
A.4.2 Sample preparation9
A.4.3 Characterization 120
A.4.4 Reference experiments0
Appendix to Chapter 44
A.4.5 Synthesis 124
A.4.6 Data 130
A.5 Appendix to Chapter 5 143
A.5.1 Synthesis 143
A.5.2 Sample preparation6
A.5.3 Selected DLS data6
A.6 Acknowledgements9
6 Self-assembly of cross-linked polymer micelles into complex higher-order aggregates
Chapter 1: Introduction
Nature achieves great complexity with only a minor number of key components. Nearly all
proteins e.g. are built up of the 21 natural amino acids, which together can be used to perform
almost all tasks necessary for the catalysis of a large number of reactions, selective binding, signal
transduction and everything else needed to maintain life. A second group of building blocks, the
ribonucleic acids (DNA and RNA) are built up of only four different units each, which is enough
to encode for all proteins present in nature and, together with a range of proteins, control the
production of all components in a living cell.
Though the basic components are simple enough, their interaction culminates in very
complex behavior, with the complexity having steadily increased during evolution. The fact that
from basic building blocks complex structures can be formed can be traced back to the ability of
the single components to specifically build structures over multiple length scales. The 21 natural
amino acids are linked to a linear amino acid chain in a specific order, encoded in the DNA. The
expression of genes in the DNA takes place by transcription into mRNA by RNA-polymerases
and subsequent translation into the corresponding peptide sequence in the ribosomes. The
primary structure of the amino acid sequence folds into secondary structures, such as α-helices, β-
sheets and turns. These structures then order into tertiary structures which are the final soma of
the proteins. The tertiary structures can assemble into quaternary structures by specific
interaction with other proteins.
In DNA and RNA a similar kind of ordering takes place. DNA forms the well-known
double helix from complementary strands of DNA, due to the specific hydrogen bonding
between two nucleotide residues (Adenine with Thymine and Cytosine with Guanine). This
secondary structure can obtain a super-ordering when certain specifically binding proteins, such
as histones and proteins associated with signal transduction, are present, or can e.g. form
supercoiled structures. RNA (only different from DNA because of an extra hydroxyl group in the
backbone and the use of Uracil instead of Thymine) does not normally form such stable
structures, but a secondary structure is often obtained through hydrogen bonding interaction
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between short stretches of nucleotides, in some cases leading to shapes that are used for the
catalysis of reactions. The most famous example of this is perhaps the way in which transfer
RNA (tRNA) is used in the recognition of triplets on the messenger RNA (mRNA) for the
translation of the RNA sequence into the amino acid chain.
Through the interaction of proteins, nucleic acids, lipid bilayers and other components
organelles are formed which together build up cells. In higher organisms these are ordered in
such a way that they form organs which are specialized in performing one or a few basic
functions. The organs in turn build up the entire organism.
Going from the basic building blocks, it becomes clear that complexity starts with only a
minor number of building blocks which act together in complex ways.
Chemistry has not even begun to approach the kind of complexity that nature achieves.
Drawing inspiration from nature, the building of complex structures by self-assembly has been
one of the major topics in chemistry in general and especially in polymer chemistry.
In polymer chemistry often only two levels of organization are achieved, namely the primary
structure of the polymer chain and the aggregates built from the single polymer chains, such as
micelles, etc. (also see Chapter 2). This work focuses on increasing the complexity of the
aggregates formed from polymer chains, firstly by trying to introduce asymmetry in the
aggregates and secondly by inducing super-organization of the primary aggregates. Asymmetric
aggregates, e.g. Janus type micelles, or vesicles with an asymmetric membrane, are formed using
aggregation motives which incorporate two different polymer chains in one aggregate. Here
either the spontaneous demixing of the polymer chains is used to obtain phase separation, or
phase separation is induced by an external stimulus. Two approaches are chosen to induce phase
separation, namely selectively influencing the solvent quality of one of the components making
up the polymer structure, or by using a template.
The materials that are obtained are strongly responsive to external stimuli, whether that is
pH, ionic strength, temperature, the presence of small molecules and ions, etc.. The influence of
these stimuli is also investigated in more detail.

8 Self-assembly of cross-linked polymer micelles into complex higher-order aggregates
Chapter 2: Background
2.1 Introduction
To be able to understand the context in which this work was performed, some background
knowledge on poly