Polymer, metal, and ceramic microtubes by strain-driven self-rolling [Elektronische Ressource] / vorgelegt von Kamlesh Kumar
163
pages
English
Documents
2009
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
163
pages
English
Documents
2009
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
Publié par
Publié le
01 janvier 2009
Langue
English
Poids de l'ouvrage
4 Mo
Polymer, Metal, and Ceramic Microtubes by Strain-driven Self-rolling D I S S E R T A T I O N zur Erlangung des akademischen Grades Doktor rerum naturalium (Dr. rer. nat.) vorgelegt am Fachbereich Chemie der Fakultät Mathematik und Naturwissenschaften der Technischen Universität Dresden von Kamlesh Kumar geboren am 19 Juli 1980 in Jaipur, Indien Gutachter: Prof. Dr. M. Stamm Prof. Dr. H.-J. P. Adler Eingereicht am: Tag der Verteidigung: Dedicated To My Family IIAcknowledgement The completion of this thesis would not have been possible without the support, hard work and endless efforts of a large number of people. I wonder if I can convey my heartfelt appreciation and gratitude in any way possible to all people who are connected direct or indirect to this thesis. I am deeply indebted to Prof. Dr. Manfred Stamm for providing me an opportunity to carry out this work in IPF, and whose guidance, advice, constant motivation and encouragement, helped me in all the time of research and writing of this thesis. The efforts and help he extended made me to feel at home. I thank my advisor Dr. Valeriy Luchnikov for his valuable guidance and help during this thesis work. His wide knowledge and constant encouragement provided a good basis for my dissertation. I am also grateful to Dr.
Voir
Publié par
Publié le
01 janvier 2009
Langue
English
Poids de l'ouvrage
4 Mo
Gutachter: Prof. Dr. M. Stamm
geboren am 19 Juli 1980 in Jaipur, Indien
von
(Dr. rer. nat.)
Self-rolling
Polymer, Metal, and Ceramic Microtubes by Strain-driven
D I S S E R T A T I O N
zur Erlangung des akademischen Grades
der Fakultät Mathematik und Naturwissenschaften
Eingereicht am:
Prof. Dr. H.-J. P. Adler
Tag der Verteidigung:
am Fachbereich Chemie
Doktor rerum naturalium
der Technischen Universität Dresden
Kamlesh Kumar
vorgelegt
Dedicated To My Family
II
Acknowledgement
The completion of this thesis would not have been possible without the support, hard work
and endless efforts of a large number of people. I wonder if I can convey my heartfelt
appreciation and gratitude in any way possible to all people who are connected direct or
indirect to this thesis.
I am deeply indebted to Prof. Dr. Manfred Stamm for providing me an opportunity to
carry out this work in IPF, and whose guidance, advice, constant motivation and
encouragement, helped me in all the time of research and writing of this thesis. The efforts
and help he extended made me to feel at home.
I thank my advisor Dr. Valeriy Luchnikov for his valuable guidance and help during this
thesis work. His wide knowledge and constant encouragement provided a good basis for my
dissertation. I am also grateful to Dr. Bhanu Nandan for the help and support which I received
from him during my stay in Dresden. The way both helped me to complete my thesis is
wonderful and it is not easy to express in words.
I gratefully acknowledge Dr. Frank Simon and Dr. Petr Formanek, respectively for their
help in XPS, SEM measurement; Dr. Martin Müller and Gudrun Adam for FTIR
measurements. I thank Mrs. P. Scheppan and Dr. U. Burkhardt from Max Planck Institute for
Chemical Physics of Solid, Dresden for their help in EDX analysis. I also thank Dr. Jens
Ingolf Mönch from Leibniz Institute for Solid State and Materials Research Dresden (IFW)
for deposition of gold patterns.
I would like to specially thank Prof. I. K. Varma for her tacit knowledge and moral
support in very difficult times. Furthermore I would like to express my gratitude to Dr. V. III
Senkovskyy for the synthesis of poly(4-bromostyrene) and Dr. A. Kiriy and Dr. E. Bhoje
Gowd for their nice suggestions during my work. I also thank to my colleagues Mukesh
Kumar Vyas, Prashant Sinha, Fabio Crobu, Smrati Gupta, Eva Herold, Marko Kuntzsch,
Konstantin Demidenok, Vera Bocharova, Martha Horchea and Sina Burket for their
cooperation and support in my work.
I would also like to thank my friends Bitu, Stefan, Prashant Menezes, Sameer,
Pradyumn, Dipti, Alok, Vishal, Vikram, Manoj, Saurabh, Satpal, Biplap, Sunil and Deepa.
Without their help would have been difficult to live so far away from family and to complete
thesis.
To my family, I thank them for always being there for me and for giving me
unconditional support and love. Words are inadequate to thank my parents, brother, and
sisters, whose inspiration, understanding, patience and support have always been a source of
encouragement in carrying out the work. I would like to specially thank Satish, Mahesh,
Mukesh, Shimbu, Neelu, Reenu, and Meenu for accommodating my work and encouraging
me to strive for more at each step.
This research work was made possible by the financial support from IPF Dresden.
IV
Abstract A thin polymer bilayer film was transformed into micro- and nano-tubes using strain driven
self-rolling phenomena of polystyrene (PS)/poly (4-vinyl pyridine) (P4VP) film. Polymer
bilayer was produced by consecutive deposition of PS and P4VP, from toluene and
chloroform solutions, respectively, by dip-coating technique. The object formation proceeds
from a opening in the film made by photolithography or by mechanical scratching followed
by immersion of patterned sample in dodecylbenzene sulfonic acid (DBSA) solution. DBSA
forms supramolecular complexes with pyridine rings of P4VP and increases the specific
volume of the polymer. Since the solution is neutral to PS layer, bilayer film develops strain
due to unequal swelling of polymers in solution of DBSA and hence the film bends and
scrolls in order to minimize its free energy and form tubes. The length of the tubes and the
direction of rolling are determined by mechanical patterning of the film. UV-photolithography
is used to fabricate patterns of polymer bilayer in order to create tube in a precise manner. The
kinetics of the tube formation was studied with respect to acidity of the solution and UV dose.
Rate of rolling increased with the acidity of the solution. Tube diameter and rate of rolling
decreased with the increase of the UV exposure time. Films with 2-dimensional gradients of
layer thicknesses were prepared to study a broad range of parameters in a single experiment.
Furthermore, polymer micro-toroids and triangles were also fabricated using self-rolling
approach of PS/P4VP layer. Moreover, the kinetics of toroid formation is also studied in the
present work. The equilibrium dimensions of toroid are determined by the balance of the
bending and the stretching energies of the film. The width of the rolled-up bilayer is larger for
the films with higher values of the bending modulus and smaller values of the effective
stretching modulus.
Moreover, self-rolling phenomena of polymer layer was also explored as a template to
fabricate metal, ceramic and metal/ceramic hybrid tube. In order to fabricate metallic and
V
bimetallic tube, the cross-linked polymer film is capped by metallic layer. After rolling,
polymer template is removed by pyrolysis resulting in pure metal microtubes. The fabrication
of silica and silica/gold hybrid tubes of high
aspect ratio is also demonstrated.
Polydimethylsiloxane (PDMS) is used as a precursor of the silica and it is converted into
silica by pyrolysis at high temperature. Entire polymer moiety is also removed at this
temperature. In order to fabricate hybrid tube of silica with gold, a thin gold layer is deposited
on the polymer layer by physical vapour deposition.
Self-rolling of polymer bilayers is a very convenient approach for interfacing the
interior of microtubes with external electrical circuits and it can be used in particular for
creating devices as micro-bubble generators exploiting electrolytic decomposition of fluids. A
demonstration of microbubble generation inside the polymer tube is shown in this work.
Possibility to functionalize the hidden walls of the tubes is one of the major advantages
of the self-rolling approach. One can modify the surface of the film prior to rolling by
magnetron sputtering of metal and upon rolling, tube and toroids with metallized inner surface
could be obtained. The tube and toroids with metallic inner surface are promising for the
future research as IR-frequency range resonators. Polymer and metallic microtubes fabricated
by self-rolling
approach may find
applications in such fields as
IR-waveguiding,
microfluidics, enzyme bi-reaction, chemical and biochemical sensing. The silica and
silica/gold
hybrid tubes have potential use in optoelectronic devices and in catalytic
applications.
VI
Chapter 1: Introduction
TABLE OF CONTENTS
1.1 Preface and Motivation 1.2 Goal 1.3 Outline Chapter 2: Mechanism of strain-driven self rolling in thin multi-layer films
2.1Theoretical background 2.2 Self-rolling of semiconductor thin films 2.3 Swelling behaviour of polymers, networks and super absorbers 2.4 Self-rolling of polymer bilayer filmsChapter 3: Experimental
1 4 5
8 12 14 17
3.1 Materials 21 3.2 Characterization techniques 3.2.1 Null ellipsometry 22 3.2.2 Optical microscopy 24 3.2.3 Fluorescence microscopy 25 3.2.4 Scanning electron microscopy 27 3.2.5 Atomic force microscopy 29 3.2.6 Infrared spectroscopy 30 3.2.7 X-ray photoelectron spectroscopy 33 3.2.8 Energy dispersive X-ray Analysis 35 Chapter 4: Formation of Self-rolled Polymer Microtubes Studied by Combinatorial
Approach
4.1Introduction 4.2Fabrication of tube 4.3Results and discussion 4.3.1Parameters affecting the diameter of tube a)Effect of the thickness of the polymer layer on the tube’s dimensions b)Effect of UV exposure dose on tube diameter
VII
39 41 42 45 46 49
c)Rate of rolling (i) The effect of UV irradiation doses on the rate of tube rolling (ii) The effect of concentration of the acidic solution on the rolling rate d) Effect of acid concentration on tube diameter 4.3.2 Fluid transport in rolled-up polymer tube 4.4 Discussion 4.5 Conclusions Chapter 5: Fabrication of polymer microtoroids
5.1Introduction 5.2Experimental 5.3Results and discussions 5.4Kinetics of micro-toroids formation 5.5Model for the micro-toroids formation 5.6Discussion 5.7Conclusions Chapter 6: Formation of metallic/bimetallic microtubes
6.1Introduction 6.2Experimental 6.3Results and Discussions 6.4Kinetics of tube formation 6.5Conclusions Chapter 7: Fabrication of silica and metal/silica hybrid tubes
7.1Introduction 7.2Experimental 7.3Results and discussion 7.4Discussion 7.5Conclusions
VIII
50 51 51 52 53 57 59
61 62 64 66 67 70 71
74 75 75 85 91
93 94 95 104 105
Chapter 8: Bubble generation inside the tube
8.1Introduction 8.2Fabrication of bubble generation device 8.3Results and discussions 8.4Discussion 8.5Conclusions Chapter 9: Summary and outlook
References
Appendixes
IX
108 110 112 120 121
123
130
146
Chapter 1
1.1 Preface and Motivation
1. Introduction
The formation of tubular structures of micron and sub-micron dimensions is an emerging
area because of potential applications of these objects in various fields such as micro and
nanofludic systems [Thu06, Teg04], wave-guide [Kip06], electronics [Tak08] and nanojet
printing [Voi01]. Mesoscopic dimensions of the tubular-based devices allow for precise control
over the tiny amounts of gas, chemicals and solvents, and permit to manipulate with the
thermodynamical parameters of the system (temperature, pressure) with high rate and precision
[Squ05, Ho98, Lel04, Het05, Mal99]. Moreover, the behaviour of fluids geometrically
constrained to small, micron and sub-micron natural or artificial compartments is known to
differ considerably from the bulk characteristics [Guo06]. Miniaturisation and reduction of the
energy requirements of these systems are additional advantages of these systems.
There exist numerous approaches to the production of micro- and nanoscale tubular
structures. The template based [Mar94] and template free [Hop04] methods are widely used to
fabricate tubes of polymers, semiconductors, metals and other materials on a micro and
nanoscopic scale. Typically, a membrane which contains nanopores of uniform diameter is
used in a template method. With the help of porous membrane monodisperse nanocylinders of
the desired material, whose dimensions can be carefully controlled, are obtained. Polymer,
metal and hybrid nano- and mesotubes can also be synthesized by coating on degradable
polymer template fibers [Bog00]. Extremely thin degradable polymer fiber templates are first
coated with the desired wall materials and later subjected to selective removal of the core
material forms the tubes.
Although the template methods of the mesotube’s fabrication are simple, cheap and
permit high output, however, they allow only reduced control over the functionalization of the
