Untra-thin films of polyvinyl alcohol on hydrophobic surfaces

173 Pages·2015·7.84 MB·English

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Doctoral Dissertations 1896 - February 2014
1-1-2004
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Mikhail, Kozlov
University of Massachusetts Amherst
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ULTRA-THIN FILMS OF POLYVINYL ALCOHOL ON HYDROPHOBIC
SURFACES: PREPARATION, PROPERTIES, CHEMISTRY, AND
APPLICATIONS
A
Dissertation Presented
by
MIKHAIL KOZLOV
Submitted to the Graduate School of the
University of Massachusetts Amherst in partial fulfillment
of the requirements for the degree of
DOCTOR OF PHILOSOPHY
September 2004
Polymer Science and Engineering
© Copyright by Mikhail Kozlov 2004
All Rights Reserved
ULTRA-THIN FILMS OF POLYVINYL ALCOHOL ON HYDROPHORir
SURFACES: PREPARATION,
PROPERTIES, CH^EMISTRY AND^^^^
APPLICATIONS
A
Dissertation Presented
by
MIKHAIL KOZLOV
Approved as to style and content by:
Thomas J. McCarthy, Chair
David A. Hoagland, Member
Mark Tuominen, Member
Shaw Ling Hsu, Department Head
Polymer Science and Engineering
ACKNOWLEDGMENTS
am
I indebted to many people who made my
graduate journey not only successful,
but also memorable and enjoyable. First, I am extremely grateful to my advisor for his
patience and support through these years, for setting a marvelous example of wisdom,
energy, and passion for science. Through all adventures of my time here, he was that
perfect mentor that each of us would be happy to have in life. I would also like to thank
my
committee members. Professors David Hoagland and Mark Tuominen, for their
clever comments and suggestions, and Professor Lesser for his valuable input in the
My
adhesion project. sincere thanks also go to Prof. Wei Chen of Mt. Holyoke College
for inspiring me to do this work, for our great discussions on and off the science topics.
I thank Presstek Corp. and Office of Naval Research for funding this research.
The McCarthy Group has been the ultimate learning playground for me. I'd like
to thank our seniors, Chris, Jeff, Chuntao, Xinqiao, and Terry, for teaching me and
helping me to get started with many things; my classmate Margarita; my frisbee-, fishing,
and officemate Kevin; my hardworking partner in the sensor project Sung In Moon; my
fellow Russian chemist Alex; our group's guardian angel Jack; Trudy Smith, a summer
student I was fortunate to work with; Ebru, like, Zhixiang, Jay, Jung Ah for the enjoyable
and productive environment they all create. I wish to also thank other wonderful PSE
scientists and staff: Jim Capistran, Jenn Famer, Lou Raboin, Greg Dabkowski, Alan
Waddon, Ted Atkins, Eileen, Joann, and Sophie; and my good friends and collaborators:
Dmytro, Alexei, Firat, Javid, Angelo, Brian, Gregoire, Sian, Donna, Matt, and Alicia.
I want to thank my parents for everything I am, and my dearest wife Natasha for
her love and her sacrifice of much of her own career for the sake of mine and our family.
iv
ABSTRACT
ULTRA-THIN FILMS OF POLYVINYL ALCOHOL ON HYDROPHOBIC
SURFACES: PREPARATION, PROPERTIES, CHEMISTRY, AND APPLICATIONS
SEPTEMBER
2004
MIKHAIL KOZLOV, M.S., MOSCOW STATE UNIVERSITY
UNIVERSITY OF MASSACHUSETTS AMHERST
Ph.D.,
Directed by: Professor Thomas McCarthy
J.
Keywords: Surface Chemistry, Adsorption, Polyvinyl Alcohol, Ultra-thin Films.
A
new approach to surface modification ofmaterials has been formulated and
explored in great detail. It was shown that polyvinyl alcohol (PVOH) quickly and
irreversibly adsorbs to hydrophobic surfaces producing smooth, continuous, hydrophilic,
robust films in the thickness range oftens of angstroms. Surfaces of all hydrophobic
materials studied could be successfully turned hydrophilic by this adsorption, which is
performed from dilute aqueous solutions ofPVOH. The ultra-thin films ofadsorbed
PVOH were studied by means of contact angle, ellipsometry, XPS, AFM, FT-IR, and
DSC. Adsorption conditions, such as time, polymer concentration and molecular weight,
temperature, salt type and concentration, and polymer composition all have an effect on
PVOH
the properties of the adsorbed film. The unique character of irreversible
adsorption among other water-soluble polymers is explained by polymer crystallization
V
that occurs concurrently with adsorption. CrystalHnity within adsorbed films IS
demonstrated by the means of FT-IR and DSC. Chemical properties ofadsorbed PVOH
were studied, and a number ofsynthetic procedures were developed for further
PVOH
modification of ultra-thin films. Cross-linking ofadsorbed PVOH imparted great
PVOH
stability in hot water. in the ultra-thin films was successfully converted into a
variety ofpolyvinyl esters and urethanes; polyethylene glycol was grafted "to" and
"from" these films. Prospective applications of PVOH adsorption and its ultra-thin films
were studied, hnproved adhesion in glued joints ofpolyethylene was demonstrated when
PVOH
was pre-adsorbed on PE before applying adhesive. PVOH adsorption and
PEG
subsequent grafting significantly reduced protein adsorption on a hydrophobic
A PVOH
surface. possibility to create defined features on surface by chemical patterning
was demonstrated. A novel design ofvapor sensing devices based on the adsorbed and
PVOH
modified was proposed and studied in detail. It was shown that remarkable
PVOH
reproducibility in adsorption on surface acoustic wave devices can be achieved
and that ftirther chemistry of the adsorbed films permits the preparation of sensitive and
selective vapor sensors.
vi
1
TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS
ABSTRACT
^
TABLE OF CONTENTS
^jj
LIST OF TABLES
x
LIST OF FIGURES
xi
CHAPTER
ADSORPTION OF POLYVINYL ALCOHOL ONTO HYDROPHOBIC
I.
SURFACES
1
Introduction
1. 1 . 1
Background
1.2. 3
PVOH
1.2. 1. adsorption 3
PVOH
1.2.2. crystallization 4
1.3. Preparation of samples 7
PVOH
L3. Substrates for adsorption 7
1 .
PVOH
1.3.2. samples 10
PVOH
1.3.3. adsorption on modified silicon wafers 11
L3.4. PVOH adsorption on expanded PTFE sheet 12
1.4. Characterization 12
1.4.1. Contact angle measurements 12
Elhpsometry 15
1.4.2.
1.4.3. Atomic force microscopy (AFM) 16
1.4.4. X-ray photoelectron spectroscopy (XPS) 17
L4.5. Infrared spectroscopy 18
1.4.6. Differential scanning calorimetry (DSC) 20
21
1.5. Results and Discussion
1.5. 1 . Effect of substrate on PVOH adsorption 2
22
L5.2. Adsorption kinetics
•
Vll
1.5.3. Effect ofpolymer concentration and molecular weight 23
1.5.4. Effect ofdegree ofhydrolysis of PVOH 97
1.5.5. Effect of salt
30
1.5.6. Effect oftemperature
^4
1.5.7. Multilayer sequential PVOH adsorption 39
PVOH
1.5.8. adsorption on expanded PTFE
'^^^"^^ 42
1.5.9. Study of crystallinity ofadsorbed PVOH by ATR-IR.
Z.".' 45
1.5.10. Study of crystallinity of adsorbed PVOH by contact angle. "1*^51
1.5.1 1. Study of crystallinity of adsorbed PVOH by DSC
54
PVOH
1.5.12. Discussion of
crystallinity 57
1.6. Conclusions
CHEMISTRY OF ADSORBED
11. ULTRA-THIN FILMS OF POLYVINYL
ALCOHOL
61
II. 1 Introduction
.
n.2. Background
^2
11.2.1. General 52
PVOH
11.2.2. Cross-linking of ^Z""Z"I""..!.r..^!63
11.2.3. Cross-linking of adsorbed PVOH by incorporation of an
inherent cross-Hnker
54
11.2.4. Surface modification with acyl chlorides 65
11.2.5. Surface modification with isocyanates 66
11.2.6. Grafting reactions 68
11.2.7. Biocompatibility and PEG grafting 68
11.2.8. Dehydration ofadsorbed PVOH 71
11.3. Experimental procedures for chemical modification of adsorbed PVOH... 72
11.3.1. Cross-linking with glutaraldehyde 72
PVOH
11.3.2. Adsorption of copolymer with an inherent cross-linker... 73
PVOH
11.3.3. Esterification of adsorbed with a series of
acyl chlorides 73
PVOH
11.3.4. Urethanation ofadsorbed with a series of isocyanates. 75
...
PEG PVOH
n.3.5. Grafting on adsorbed 77
PVOH
II.3.6. Dehydration ofadsorbed 78
n.3.7. Calculation ofreaction yield 78
11.4. Results and Discussion 81
PVOH
11.4. 1 . cross-linking with glutaraldehyde 81
PVOH
11.4.2. adsorption and cross-linking with an inherent
cross-linker 87
PVOH
11.4.3. Esterification of adsorbed with acyl chlorides 90
viii