Utilizing pollen as a bio-organic template for tailorable multimodal adhesion

167 Pages·2013·6.03 MB·English

UTILIZING POLLEN AS A BIO-ORGANIC TEMPLATE FOR
TAILORABLE MULTIMODAL ADHESION

A Thesis
Presented to
The Academic Faculty

by

Ismael J. Gomez

In Partial Fulfillment
of the Requirements for the Degree
Doctor of Philosophy in the
School of Chemical and Biomolecular Engineering

Georgia Institute of Technology
December 2013

COPYRIGHT 2013 BY ISMAEL J. GOMEZ
UTILIZING POLLEN AS A BIO-ORGANIC TEMPLATE FOR
TAILORABLE MULTIMODAL ADHESION

Approved by:

Dr. J. Carson Meredith, Advisor Dr. Yulin Deng
School of Chemical and Biomolecular School of Chemical and Biomolecular
Engineering Engineering
Georgia Institute of Technology Georgia Institute of Technology

Dr. Haskell Beckham Dr. Yonathan Thio
School of Materials Science & Engineering School of Chemical and Biomolecular
Georgia Institute of Technology Engineering
Georgia Institute of Technology

Dr. Sven Behrens
School of Chemical and Biomolecular
Engineering
Georgia Institute of Technology
Date Approved: October 8, 2013(cid:13)
This work is dedicated to my family.
ACKNOWLEDGEMENTS

I would like to thank my family for giving me the strength and support needed to
complete my education. To my parents, Ana and Ismael Gomez, the sacrifices you have
made to provide me with the opportunity to obtain an education have always motivated
me to succeed. Thank you for all your love and inspiration throughout my life. To my
siblings, Tiffany, Adrian, and Adam, you’ve always been my best friends and kept me
grounded. Thank you for all the laughs and encouragement you have given me during my
time away from home. To my Grandma Violeta, the love and prayers you have given me
have helped me succeed in all my endeavors. Finally, to my Great Grandmother, Mama
Tere, thank you for always believing in me and watching over me from heaven.
I am especially grateful to my advisor, Dr. Carson Meredith, for being an
inspiring mentor during my graduate career. Your support and encouragement have been
invaluable to my growth and development. Most importantly, you have helped me
become a well-rounded person by teaching me the importance of integrity, a strong work
ethic, and attaining a work-life balance. I would like to thank my committee members,
Dr. Haskell Beckham, Dr. Sven Behrens, Dr. Yulin Deng, and Dr. Yonathan Thio for
providing me with valuable feedback and support throughout my PhD education. Special
appreciation is given to my collaborators, Dr. Ken Sandhage and Brandon Goodwin, for
their contributions to my work. Additionally, I would like to acknowledge the
organizations that provided funding for my research: Dow Chemical and the U.S. Air
Force Office for Scientific Research.
I would like to express my gratitude to the professors that have shaped the course
of my education. I thank Dr. Ken Smith for providing me with guidance during my time
at MIT and encouraging me to pursue a graduate degree. I am grateful to Dr. Paula
iv
Hammond for providing me with the opportunity to perform research as an undergraduate
student. The year I spent in your lab provided me with a strong foundation that has
enabled me to succeed as a PhD student. I’d like to thank my high school chemistry
teacher, Ms. Sharon Veenhoff, for challenging and enlightening me throughout high
school. Your guidance has undoubtedly contributed to all my academic success. I am also
very thankful to Dr. Sue Ann Bidstrup-Allen for giving me the opportunity to become a
mentor and leader through the Exxon-Mobil Success Program. This experience has given
me a unique opportunity to grow as a person and become a role-model for other students.
I thank all the current and past members of the Meredith research group, Dr. Keith
Reed, Dr. Jung-Hyun Lee, Dr. Reginald Thio, Jie Wu, Dr. Haisheng Lin, Dr. Sangil Han,
Timi Fadiran, Natalie Girouard, Dr. Shanhong Xu, Yi Zhang and Donglee Shin, for
sharing your knowledge and friendships with me. I appreciate all the discussions,
collaborations, and laughs we’ve shared throughout my time in the group.
Lastly, I’d like to thank my friends, not already mentioned, who have contributed
to my quality of life during my time at Georgia Tech. I’d like to give special thanks to
Kathleen Vermeersch for sharing many adventures with me and supporting me
throughout my PhD education. I’d also like to thank Erin Redmond, Stephanie Didas,
Jonathan Rubin, Aubrey Tiernen, Vyran George, Hector Beltran, and Esteban Felix for
all their support.

v
TABLE OF CONTENTS
ACKNOWLEDGEMENTS iv
LIST OF TABLES x
LIST OF FIGURES xi
SUMMARY xvi
Chapter 1 Introduction and Background 1
1.1 Designing Microstructured Particles 1
1.1.1 Fabrication of Microstructured Particles 1
1.1.2 Structured Particles Derived from Nature 3
1.2 Pollen as a Biotemplate 4
1.2.1 Pollen sustainability 4
1.2.2 Pollen chemistry 5
1.2.3 Pollen Transport Properties 9
1.2.4 Pollen-based Hybrid Materials 11
1.3 Characterizing the Adhesion of Pollen-Derived Particles 12
1.4 Thesis Overview 14
1.5 References 14
Chapter 2 Quantifying the Structural Factors Contributing to Pollen Grain Adhesion
22
2.1 Overview 22
2.2 Introduction 22
2.3 Experimental 24
2.3.1 Materials and Procedure 24
2.3.2 Experimental Methods 28
2.4 Results and Discussion 29
v i
2.4.1 Pollen and Substrate Morphology 29
2.4.2 Cleaned Pollen Adhesion 33
2.4.3 Mechanism of Cleaned Pollen Adhesion 35
2.5 Conclusions 37
2.6 References 38
Chapter 3 Preparation of Metal Nanoparticle-Coated Pollen Particles for Enhanced
Short-Range van der Waals Adhesion and Raman Scattering 41
3.1 Overview 41
3.2 Introduction 41
3.3 Experimental 43
3.3.1 Materials and Procedure 43
3.3.2 Experimental Methods 46
3.4 Results and Discussion 49
3.4.1 Pollen Preparation 49
3.4.2 Pollen-Nanoparticle Composite Preparation 53
3.4.3 Nanoparticle-Pollen Composite Adhesion 62
3.4.4 Nanoparticle-Pollen Composite Effectiveness as SERS Substrates 68
3.5 Conclusions 70
3.6 References 71
Chapter 4 Conversion of Pollen Particles into Three-Dimensional Ceramic Replicas
Tailored for Multimodal Adhesion 78
4.1 Overview 78
4.2 Introduction 78
4.3 Experimental 80
4.3.1 Material and Procedure 80
4.3.2 Experimental Methods 81
vi i
4.4 Results and Discussion 83
4.4.1 Pollen Replica Preparation 83
4.4.2 Pollen and Pollen Replica Adhesion 89
4.5 Conclusions 99
4.6 References 100
Chapter 5 Tuning the Long-Range Magnetic Force of Three-Dimensional Magnetic
Pollen Replicas 106
5.1 Overview 106
5.2 Theory 107
5.3 Experimental 109
5.3.1 Materials and Procedure 109
5.3.2 Experimental Methods 110
5.4 Results and Discussion 113
5.4.1 Pollen Replica Characterization 113
5.4.2 Pollen Replica Adhesion Results 116
5.4.3 Modeling of the Magnetic Forces 122
5.4.4 Fe O Replica Magnetic Force Results 125
3 4
5.4.5 Modeling the Magnetic Force of Fe O Replicas 127
3 4
5.5 Conclusions 129
5.6 References 130
Chapter 6 Conclusions and Recommendations 132
6.1 Summary and Conclusions 132
6.1.1 Quantify the dependence of pollen adhesion on exine size and shape
using colloidal AFM 132
6.1.2 Control the deposition of nanoparticles onto pollen using electrostatic
interactions to modify pollen’s adhesive properties and impart optical
functionality 132
vi ii
6.1.3 Utilize pollen as a template in the surface sol-gel fabrication of replicas
possessing magnetic behavior 133
6.1.4 Tune the magnetic attraction of the pollen replicas and model the long-
range magnetic interactions of the replicas using a permanent magnet as a probe.
134
6.2 Recommendations for Future Work 135
6.2.1 Investigate the influence of surface roughness on pollen and pollen
replica adhesion 135
6.2.2 Investigate the adhesion enhancement of natural pollenkitt coating on
synthesized pollen-derived particles 135
6.2.3 Optimize nanoparticle-pollen composites for effective SERS substrates
136
6.2.4 Tunability of short-range pollen replica adhesion (crystal size) 137
6.3 References 138
Appendix A Fortran Code for Magnetostatic Potential and Magnetic Field of an
Neodymium Disk Permanent Magnet 140
A.1 Adaptation of FORTRAN simulation 140
A.2 References 150
ix
LIST OF TABLES
Table 1.1. Characteristic surface structures of pollen grains. ........................................... 10
Table 2.1. Surface roughness and static water contact angles of the various substrates. . 30
Table 2.2. Morphology characteristics of pollen samples. ............................................... 33
Table 3.1. Size of ragweed pollen’s characteristic features after exine shell isolation and
APTES functionalization. ................................................................................................. 52
Table 3.2. Average measured values of adhesion, measured spike tip radius, and
calculated contact radius. .................................................................................................. 66
Table 4.1. Average surface roughness (Ra, in nm) of the substrates used in this study.. . 91
Table 4.2. Average measured values of adhesion force, calculated Hamaker constants,
and calculated contact radii.. ............................................................................................. 95
Table 5.1. Range of cantilever probe spring constants (N/m) used in this study. .......... 111
Table 5.2. Measured diameters of coated sunflower, α-Fe2O3 replicas, and Fe3O4
replicas of varying SSG deposition cycles (10-50 layers). ............................................. 113
Table 5.3. Average adhesion forces for cleaned sunflower, α-Fe2O3 sunflower replicas,
and Fe3O4 sunflower replicas of various coating layers for all substrates investigated. 121

x