engineering polymer surface chemistry and topography via additive migration and physical ...

251 Pages·2011·5.07 MB·English

by  Hongyan Gu

ENGINEERING POLYMER SURFACE
CHEMISTRY AND TOPOGRAPHY VIA
ADDITIVE MIGRATION AND PHYSICAL
SECTIONING

BY
HONGYAN GU, B. Eng., M. Eng.

A Thesis
Submitted to the School of Graduate Studies
in Partial Fulfillment of the Requirements
for the Degree
Doctor of Philosophy

McMaster University
© Copyright by Hongyan Gu, June 2011
ENGINEERING POLYMER SURFACE CHEMISTRY AND TOPOGRAPHY
DOCTOR OF PHILOSOPHY (2011) McMaster University
(Chemical Engineering) Hamilton, Ontario

TITLE: Engineering Polymer Surface Chemistry and Topography via
Additive Migration and Physical Sectioning

AUTHOR: Hongyan Gu,
B. Eng. (Zhejiang University)
M. Eng. (Zhejiang University)

SUPERVISOR: Professor Shiping Zhu

NUMBER OF PAGES: xxxii, 218

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Abstract
Advanced polymer surface modification technologies allow modification
of polymers with various functionalities or robustness to environment. However,
existing technologies are still facing challenges in modifying plastic parts that
have large dimensions or complex geometries. Furthermore, to obtain long-
lasting surface modification, some materials must be surface-treated with plasma
or harsh chemicals, and such pretreatments significantly complicate operations
and increase costs.

We proposed a surface-active-additive (surfadditive) approach that is
fundamentally different from existing post-treatment methods for surface
chemistry modification. Our strategy was to design a type of additives that
migrate to the surface of a plastic part during manufacturing and entangles with
bulk polymer chains to achieve stable surface properties. Two types of
surfadditives were synthesized in this work. The first type is a block copolymer
having the “head-neck-body” structure. The “head” and “neck” of the chain
molecule consist of a low-surface-energy component such as fluorinated segments
and a reactive component such as triethoxy silane. The “body” of the surfadditive
is polymethyl methacrylate (PMMA), which is designed for applications in acrylic
plastics. The second type of surfadditives is hybrid magnetic material, which was
synthesized by grafting polymer chains that contain nanosilica cages and PMMA
iii
backbone from iron nanoparticles. The polymeric surfadditives were applied in
the injection molding and casting processes of PMMA. The effect of processing
temperature, surfadditive structure, concentration, and mold material on the
surface modification were investigated.

In exploring new surface physical property modification techniques, we
developed a new one-step nanopatterning method for topography construction that
is based on chattering. Chatters are unwanted wavy structures generated from
vibrations in cutting. They are mostly random in size because of uncontrolled
vibration frequencies. Using an oscillating diamond knife with tunable oscillation
frequency in ultramicrotomy, we succeeded in obtaining control over chattering.
This “controlled chattering” method was demonstrated to be an excellent
technology to fabricate wavy surface patterns on a variety of materials including
thermoplastic, thermosetting and soft metals. The size of wavy patterns prepared
by this method was tunable from 30 nm to micrometer scale through adjusting
cutting speed and oscillation frequency. The effects of materials’ mechanical
properties and cutting speed on the pattern formation were systematically
investigated. In addition, the controlled chattering was also extended to the
fabrication of one-dimensional polymer and metal nanowires with ultra-high
aspect ratios up to 104. Different morphologies such as nanoribbons, nanorods
were obtained through oscillation phase adjustment. The size of nanowires was
found tunable through adjusting cutting depth, cutting speed, as well.
iv
Acknowledgements
First and foremost, I would like to express my deepest gratitude to my
supervisor, Dr. Shiping Zhu, for his continuous guidance, encouragement and
support during my PhD study. His dedication to work, insight into science, and
concern about students really impressed me and had been a source of motivation
for me to achieve my goals. I treasure all the advices and trainings received from
him, without these, I would never have grown and been stimulated so much. I
simply could not wish for a better and friendlier supervisor.
I’m also grateful to Dr. Santiago Faucher, who co-supervised part of my
thesis and provided me with lots of useful discussions and suggestions. He is an
intelligent, passionate and capable person from whom I have a lot to learn.
I thank my committee members, Dr. John Vlachopoulos and Dr. Gianluigi
Botton for their inspiring discussions and valuable advices.
It has been my best experience to work in the Zhu group with so many
great people. My appreciation is extended to Dr. Junwei Zhang, Dr. Wei Feng,
Dr. Renxu Chen, Dr. Xiang Gao, Dr. Zhilin Jin, Dr. Zhenggang Xiao, Rachel
Gong, Sara Alibeik, Mark Machado, Mohammad Haj-Abed, Jason Doggart, Tom
Kowpak, Mark Rattle, Meng Li, Hongyu Lu, Weifeng Liu, Rummana Syeda, Cam
Derry, who helped and supported my research. I especially thank Nels Grauman
v
who helped me with some revision work and contributed lots of time to the group
activities.
I would also like to thank Dr. Carlos Filipe for providing me generous
access to their UV spectrometer for diffusion experiments. I am grateful to Dr.
Yang Chen, Dr. Nick Burke (Chemistry and Chemical Biology), Dr. Zhilin Peng
(Centre for Emerging Device Technology), Dr. Ravi Selvaganapathy, Dr. Stephen
Veldhuis, Dr. Michael Bruhis (Mechanical Engineering), Dr. An-chang Shi, Dr.
David Venus (Physics and Astronomy) for helpful discussions. Marcia Reid from
Electron Microscopy Facility helped me a lot in preparing samples and was
always willing to help.
The department of Chemical Engineering provided me with a great
environment for study and research. Kathy Goodman, Lynn Falkiner, Naci Cole,
Doug Keller, Justyna Derkach, Dan Wright have always been very helpful. Paul
Gatt is the most handy and efficient technician I have ever known. Without his
help, my thesis would never have been completed.
I appreciate the financial supports from Natural Science and Engineering
Research Council, and Ontario Centre of Excellence.
Finally, I thank my parents, my brother and my husband Huaifeng Hua for
their selfless love and support throughout all these years. I am most grateful to
my husband for giving me constant encouragement in the pursuit of my goals.
vi
Preface
The thesis is of the sandwich style and is based on the following journal
articles or manuscripts:
 Gu H.; Zhang J., Faucher S.; Zhu S. Novel polymeric surfadditives
synthesized via atom transfer radical polymerization and their surface
migration properties. Macromolecular Reaction Engineering, 2011, in press.
 Gu H.; Faucher S., Zhu S. Magnetic organo-silica nanoparticles for localized
polymer surface modification, Macromolecular Materials and Engineering
2011, accepted for publication.
 Gu H.; Zhang J.; Faucher S.; Zhu S., Controlled chattering - a new “cutting
edge” technology for nanofabrication, Nanotechnology, 2010, 21: 355302.
 Gu H.; Faucher S.; Zhu S. Controlled Chattering on PMMA and epoxy: effect
of crosslinking and cutting speed on pattern formation, Polymer, 2011, 52:
2525-2531.
 Gu H.; Zhu S. A mechanical approach for the fabrication of polymer and
metal nanowires, Nanotechnology, 2011, 22: 265355.
 Gu H.; Faucher S.; Zhu S. Diffusion of semi-flexible polyelectrolyte through
nanochannels, AIChE Journal, 2010, 56(7): 1684-1692.
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Table of Contents
Abstract ............................................................................................... iii
Acknowledgements ..............................................................................v
Preface ................................................................................................ vii
Table of Contents ............................................................................. viii
List of Schemes .................................................................................. xv
List of Figures.................................................................................. xvii
List of Tables .................................................................................. xxvi
Nomenclature ................................................................................ xxvii

Chapter 1 Introduction .......................................................................1
1.1 Background ............................................................................................................. 1
1.1.1 Coating and Polymer Surface Modification ...................................................... 1
1.1.2 Polymer Migration/ Segregation and Surface Modification.............................. 3
1.1.3 Atom Transfer Radical Polymerization and Functional Polymer Synthesis ..... 8
1.1.4 Surface Modification by Polymer Grafting ..................................................... 10
1.1.5 Challenges in Surface Modification and Surfadditive Proposal ...................... 12
1.2 Surface Topography Modification/ Patterning .................................................. 15
1.2.1 Current Techniques of Surface Patterning ...................................................... 15
1.2.2 Chatters in Imbalanced Cutting ....................................................................... 16
1.2.3 A Precision Cutting Tool: Ultramicrotome ..................................................... 17
viii
1.2.4 The Proposal of Controlled Chattering ........................................................... 20
1.3 References .............................................................................................................. 21

Chapter 2 Research objectives and thesis outline ......................... 30
2.1 Research Objectives.............................................................................................. 30
2.2 Thesis Outline ....................................................................................................... 31

Chapter 3 Novel polymeric surfadditives synthesized via atom
transfer radical polymerization and their surface migration
properties ........................................................................................... 35
3.1 Abstract ................................................................................................................. 36
3.2 Introduction .......................................................................................................... 36
3.3 Experimental Section............................................................................................ 39
3.3.1 Materials .......................................................................................................... 39
3.3.2 Synthesis of Functionalized ATRP Initiators .................................................. 41
3.3.3 Synthesis of TEOSi-FMA-MMA Block Copolymer ...................................... 42
3.3.4 Synthesis of PFO-SiMA-MMA Block Copolymer ......................................... 43
3.3.7 Characterization Methods................................................................................ 46
3.4 Results and Discussion ......................................................................................... 47
3.4.1 Synthesis of Surfadditives ............................................................................... 47
3.4.1 Characterization of Surfadditives .................................................................... 53
3.4.2 Effect of Processing Temperature on Surface Modification ........................... 56
3.4.3 Effect of Surfadditive Concentration on PMMA Surface Modification ......... 58
ix