Hydrogel Micro and Nanoparticles E-Book

• Herausgeber: Wiley-VCH
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 762

Veröffentlichungsjahr: 2012

Beschreibung

The book provides experienced as well as young researchers with a topical view of the vibrant field of soft nanotechnology. In addition to
elucidating the underlying concepts and principles that drive continued innovation, major parts of each chapter are devoted to detailed discussions of potential and already realized applications of micro- and nanogel- based materials. Examples of the diverse areas impacted by these materials are biocompatible coatings for implants, films for controlled drug release, self-healing soft materials and responsive hydrogels that react to varying pH conditions, temperature or light.

Leseprobe

Contents

Cover

Related Titles

Title Page

Copyright

List of Contributors

Foreword

Preface

Chapter 1: Thermally Sensitive Microgels: From Basic Science to Applications

1.1 Introduction

1.2 Theoretical Background

1.3 Basic Physics of Microgels

1.4 Applications

1.5 Conclusions

Abbreviations

Acknowledgments

References

Chapter 2: Thermosensitive Core–Shell Microgels: Basic Concepts and Applications

2.1 Introduction

2.2 Volume Transition in Single Particles

2.3 Concentrated Suspensions: 3D Crystallization

2.4 Particles on Surfaces: 2D Crystallization

2.5 Concentrated Suspensions: Rheology

2.6 Core–Shell Particles as Carriers for Catalysts

2.7 Conclusion

Acknowledgment

References

Chapter 3: Core–Shell Particles with a Temperature-Sensitive Shell

3.1 Introduction

3.2 Preparation of Core–Shell Particles with a Temperature-Sensitive Shell

3.3 Preparation of Hairy Particles with Temperature-Sensitive Hair

3.4 Properties, Functions and Applications of Core–Shell Particles with a Temperature-Sensitive Shell

3.5 Conclusions

References

Chapter 4: pH-Responsive Nanogels: Synthesis and Physical Properties

4.1 Introduction

4.2 Preparation Techniques for pH-Responsive Nanogels

4.3 Structural Properties of pH-Responsive Nanogels

4.4 Swelling of pH-Responsive Nanogels

4.5 Rheological Behavior of pH-Responsive Nanogels

4.6 Approach to Model pH-Responsive Nanogel Properties

4.7 Osmotic Compressibility of pH-Responsive Nanogels in Colloidal Suspensions

4.8 Conclusions and Future Perspectives

References

Chapter 5: Poly(N-Vinylcaprolactam) Nano- and Microgels

5.1 Introduction

5.2 Poly(N-Vinylcaprolactam): Synthesis, Structure and Properties in Solution

5.3 Thermal Behavior of Poly(N-Vinylcaprolactam) in Water

5.4 PVCL Nano- and Microgels

5.5 Conclusions

References

Chapter 6: Doubly Crosslinked Microgels

6.1 Introduction

6.2 Methods of Preparation

6.3 Methods of Characterization

6.4 Morphology

6.5 Properties

6.6 Potential Applications

6.7 Conclusion

References

Chapter 7: ATRP: A Versatile Tool Toward Uniformly Crosslinked Hydrogels with Controlled Architecture and Multifunctionality

7.1 Incorporating Crosslinking Reactions into Controlled Radical Polymerization

7.2 Effect of Network Homogeneity on Thermoresponsive Hydrogel Performance

7.3 Gel Networks Containing Functionalized Nanopores

7.4 Toward Micro- and Nano-Sized Hydrogels by ATRP

Acknowledgments

References

Chapter 8: Nanogel Engineering by Associating Polymers for Biomedical Applications

8.1 Introduction

8.2 Preparation of Associating Polymer-Based Nanogels

8.3 Functions of Self-Assembled Nanogels

8.4 Application of Polysaccharide Nanogels to DDS

8.5 Integration of Nanogels

8.6 Conclusion and Perspectives

References

Chapter 9: Microgels and Biological Interactions

9.1 An Introduction to Polymer Biomaterials

9.2 Drug Delivery

9.3 Biomaterial Films

9.4 Conclusion

References

Chapter 10: Oscillating Microgels Driven by Chemical Reactions

10.1 Introduction

10.2 Types of Oscillating Microgels

10.3 Synthesis and Fabrication of Oscillating Microgels

10.4 Control of Oscillatory Behavior

10.5 Flocculating/Dispersing Oscillation

10.6 Concluding Remarks

Acknowledgments

References

Chapter 11: Smart Microgel/Nanoparticle Hybrids with Tunable Optical Properties

11.1 Introduction

11.2 Synthesis of Hybrid Gels

11.3 Characterization of Hybrid Gels

11.4 Hybrid Microgels with Plasmon Properties

11.5 Photoluminescent Hybrid Microgels

11.6 Summary

Acknowledgments

References

Chapter 12: Macroscopic Microgel Networks

12.1 Introduction and Motivation

12.2 Preparation of Microgel Networks

12.3 Applications of Microgel Networks

12.4 Conclusions and Future Outlook

References

Chapter 13: Color-Tunable Poly (N-Isopropylacrylamide) Microgel-Based Etalons: Fabrication, Characterization, and Applications

13.1 Introduction

13.2 Microgel-Based Photonic Materials

13.3 Conclusions and Future Directions

References

Chapter 14: Crystals of Microgel Particles

14.1 Introduction

14.2 Theoretical Background and Experimental Methods

14.3 Determining and Modeling the Particle Form Factor

14.4 Structure Factor of Concentrated Suspensions

14.5 Final Remarks and Future Directions

Acknowledgment

References

Chapter 15: Dynamical Arrest and Crystallization in Dense Microgel Suspensions

15.1 Introduction

15.2 Methods

15.3 Synthesis and Responsive Properties

15.4 Structural and Dynamic Properties of Neutral Microgels

15.5 Structural and Dynamic Properties of Soft and Weakly Charged Microgels

15.6 Conclusions and Outlook: Probing Anisotropic Interactions

15.7 Acknowledgment

References

Index

Related Titles

Tadros, T. F.

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2012

ISBN: 978-3-527-32941-0

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Fernandez-Nieves, A., Wyss, H., Mattsson, J., Weitz, D. A. (eds.)

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Tadros, T. F. (ed.)

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Rheology of Dispersions

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ISBN: 978-3-527-32003-5

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© 2012 Wiley-VCH Verlag & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany

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Cover Design Grafik-Design Schulz, Fußgönheim

Typesetting Thomson Digital, Noida, India

List of Contributors

Kazunari Akiyoshi

Kyoto University

Department of Polymer Chemistry

Katsura Campus, Room 317, Bldg. A3

Kyoto daigaku-katsura

Nishikyo-ku

Kyoto 615–8530

Japan

Matthias Ballauff

Helmholtz-Zentrum Berlin für Materialien und Energie

Soft Matter and Functional Materials

Hahn-Meitner-Platz 1

14109 Berlin

Germany

Matthew C.D. Carter

University of Alberta

Department of Chemistry

11227 Saskatchewan Drive

Edmonton

Alberta T6G 2G2

Canada

Cheng Cheng

RWTH Aachen

DWI an der RWTH Aachen e.V.

Pauwelsstraße 8

52056 Aachen

Germany

He Cheng

State Key Laboratory of Polymer Physics and Chemistry

Joint Laboratory of Polymer Science and Materials

Beijing National Laboratory for Molecular Sciences

Institute of Chemistry

CAS, Beijing 100190

P. R. China

Jerome Crassous

Lund University

Physical Chemistry Chemical Center

P. O. Box 124

22100 Lund

Sweden

Alberto Fernández-Nieves

Georgia Institute of Technology

School of Physics

Atlanta

GA

USA

Urs Gasser

Paul Scherrer Institut

Laboratory for Neutron Scattering

5232 Villigen PSI

Switzerland

Thomas Hellweg

Universität Bielefeld

Fakultät für Chemie, Biophysikalische Chemie (PC III)

33501 Bielefeld

Germany

Ian N. Heppner

University of Alberta

Department of Chemistry

11227 Saskatchewan Drive

Edmonton

Alberta T6G 2G2

Canada

Todd Hoare

McMaster University

Department of Chemical Engineering

1280 Main St. W.

Hamilton

Ontario L8S 4L7

Canada

Liang Hu

University of Alberta

Department of Chemistry

11227 Saskatchewan Drive

Edmonton

Alberta T6G 2G2

Canada

Zhibing Hu

University of North Texas

Department of Physics

Denton

TX

USA

Matthias Karg

Universität Bielefeld

Fakultät für Chemie, Biophysikalische Chemie (PC III)

33501 Bielefeld

Germany

Haruma Kawaguchi

Kanagawa University

Faculty of Engineering

3-27-1 Rokkakubashi

Kanagawa-ku

Yokohama 221-8686

Japan

Tomasz Kowalewski

Carnegie Mellon University

Department of Chemistry

4400 Fifth Avenue

Pittsburgh

PA 15213

USA

Wenwen Li

Carnegie Mellon University

Department of Chemistry

4400 Fifth Avenue

Pittsburgh

PA 15213

USA

Juan José Liétor-Santos

Georgia Institute of Technology

School of Physics

Atlanta

GA 30332–0430

USA

Yan Lu

Helmholtz-Zentrum Berlin für Materialien und Energie

Soft Matter and Functional Materials

Hahn-Meitner-Platz 1

14109 Berlin

Germany

L. Andrew Lyon

Georgia Institute of Technology

School of Chemistry and Biochemistry & Petit Institute for Bioengineering

and Bioscience

Atlanta

Georgia 30332-0400

USA

Krzysztof Matyjaszewski

Carnegie Mellon University

Department of Chemistry

4400 Fifth Avenue

Pittsburgh

PA 15213

USA

Priti Mohanty

Lund University

Physical Chemistry

Chemical Center

P.O. Box 124

22100 Lund

Sweden

and

University of Fribourg

Adolphe Merkle Institute

Route de l'Ancienne Papeterie CP 209

1723 Marly 1

Switzerland

Jung Kwon Oh

Concordia University

Department of Chemistry and Biochemistry

7141 Sherbrooke Street West,

Montreal

Quebec H4B 1R6

Canada

Divya Paloli

University of Fribourg

Adolphe Merkle Institute

CH-1723 Marly

Switzerland

and

Lund University

Physical Chemistry

Department of Chemistry

SE-221 00 Lund

Sweden

Andrij Pich

RWTH Aachen

DWI an der RWTH Aachen e.V.

Pauwelsstraße 8

52056 Aachen

Germany

Yoshihiro Sasaki

Kyoto University

Department of Polymer Chemistry

Katsura Campus, Room 317, Bldg. A3

Kyoto daigaku-katsura

Nishikyo-ku

Kyoto 615–8530

Japan

Brian R. Saunders

The University of Manchester

Polymer Science and Technology Group, School of Materials

Grosvenor Street

Manchester M13 9PL

UK

Peter Schurtenberger

Lund University

Physical Chemistry

Chemical Center

P.O. Box 124

22100 Lund

Sweden

Michael J. Serpe

University of Alberta

Department of Chemistry

11227 Saskatchewan Drive

Edmonton

Alberta T6G 2G2

Canada

Janelle B. Smiley-Wiens

University of Alberta

Department of Chemistry

11227 Saskatchewan Drive

Edmonton

Alberta T6G 2G2

Canada

Michael H. Smith

Georgia Institute of Technology

School of Chemistry and Biochemistry & Petit Institute for Bioengineering

and Bioscience

Atlanta

Georgia 30332-0400

USA

Courtney D. Sorrell

University of Alberta

Department of Chemistry

11227 Saskatchewan Drive

Edmonton

Alberta T6G 2G2

Canada

Antoinette B. South

Georgia Institute of Technology

School of Chemistry and Biochemistry & Petit Institute for Bioengineering

and Bioscience

Atlanta

Georgia 30332-0400

USA

Daisuke Suzuki

Shinshu University

Faculty of Textile Science & Technology

3-15-1, Tokida, Ueda

Nagano 386-8567

Japan

Daisuke Suzuki

Shinshu University

International Young Researchers Empowerment Center

3-15-1, Tokida, Ueda

Nagano 386-8567

Japan

K.C. Tam

Waterloo Institute for Nanotechnology, University of Waterloo

Department of Chemical Engineering

200 University Avenue West

Waterloo

Ontario N2L 3G1

Canada

B.H. Tan

Institute of Materials Research and Engineering (IMRE)

A∗STAR (Agency for Science, Technology & Research)

3 Research Link

Singapore 117602

J.P.K. Tan

Institute of Bioengineering and Nanotechnology (IBN)

A∗STAR (Agency for Science, Technology and Research)

3 Research Link

Singapore 117602

Jeong Ae Yoon

Carnegie Mellon University

Department of Chemistry

4400 Fifth Avenue

Pittsburgh

PA 15213

USA

Guangzhao Zhang

University of Science and Technology of China

The Hefei National Laboratory for Physical Sciences at Micro-scale

Department of Chemical Physics

Hefei 230026

China

Jun Zhou

University of North Texas

Department of Physics

Denton

TX

USA

Foreword

In the unlikely event that you have opened this book without knowing anything about microgels, we start with a definition. Microgels are solvent swollen polymer networks (i.e. a type of gel) present as discrete particles with average diameters in the range 20 nm to 50 µm. Although Baker's first explicit description of microgels in 1949, describes solvent swellable polybutadiene particles, most of the microgel literature concentrates on aqueous microgels (hydrogels) in the size range 100 to 1000 nm. Generalizing more, most of the aqueous microgel publications involve crosslinked poly(N-isopropylacrylamide), PNIPAM, or related polymers showing lower critical solution temperature (LCST) behaviors. Microgel technologies have their roots in latex emulsion polymerization, which is one of the most important historical advances in polymer technology. I mention emulsion polymerization because of the parallels between latex and microgel technologies. Both involve colloidally stable, nano-scale particles with very high specific surface areas and low viscosities. Instrumentation, techniques, and colloidal theories perfected with the advent of monodisperse latexes in the 1960–1980 period are now used to characterize microgels. The ability to apply microelectrophoresis, light scattering, particulate rheology, high performance titrations and small angle neutron scattering to microgel characterization gives researchers a much larger characterization toolbox compared to those working with macrogels.

Microgel research dramatically expanded with the advent of PNIPAM microgels. We made the first PNIPAM microgel in 1978 and we were allowed to publish the work 1986, followed by the first description of a polystyrene-core-PNIPAM shell latex or microgel in 1988 – the definitions blur when considering solid core-gel shell particles. In my opinion, the large number of subsequent microgel publications arises for two reasons. First, microgels based on LCST polymers are extremely easy to make, modify and purify - one does not have to be a highly skilled synthetic polymer chemist to prepare microgels. Second, easy to measure properties including electrophoretic mobility and hydrodynamic particle size from dynamic light scattering, are sensitive functions of temperature, pH, and the presence of surfactants, proteins and other solutes.

The ease of PNIPAM microgel synthesis is a direct consequence of the LCST behavior of PNIPAM. Indeed, I believe that this link to microgel synthesis is the most important consequence of the temperature sensitivity of PNIPAM and related polymers – there are few applications that actually exploit the temperature sensitivity. The importance of the LCST, or more correctly cloud behavior, in microgel preparation is illustrated by comparing the synthesis of PNIPAM microgels to polyacrylamide microgels. When polymerizing N-isopropylacrylamide in water above the cloud point, the growing polymer chains phase separate (coil-to-globule transition) leading to homogeneous nucleation of dispersed, microgel particles. The PNIPAM particle formation mechanism is analogous to the surfactant-free polymerization of styrene. By contrast, there are very few publications involving crosslinked polyacrylamide microgels because they are difficult to make, and nearly impossible to make as uniform particles. Polyacrylamide is water soluble and does not spontaneously yield microgels. Instead, polyacrylamide microgels must be prepared by a more complex procedure, such as pre-emulsification of aqueous monomer in oil followed by polymerization.

In 2000 I published a review summarizing microgel science and technology – this would be a daunting task now because of the volume of work in the last decade. The ranges of activities summarized in the following chapters highlight the breadth and complexity of the microgel landscape. I finish this essay with my biased view of the main trends in microgel research, and as well, some unanswered questions that have nagged me over they years.

Trend 1 – Applications: In line with the general trends in modern chemistry/material science, microgel publications include a strong emphasis on potential applications. In many cases the potential applications appear to be added as an afterthought, presumably to justify the work; in a few cases the application is the main emphasis and microgels are a means to an end. From my earliest days working with microgels, I have believed there must exist some good applications for microgels. In view of the volume of microgel literature with links to potential applications, many others must feel the same. Some early outstanding examples are Pichot's body of work using microgels as platforms for bioassays, and Asher's concept of responsive microgel-based colloidal arrays. Many clever and more recent examples are found in the following chapters. Nevertheless, one can argue that a “killer application” has yet to surface. To the best of my knowledge, aqueous synthetic microgels are not manufactured in large scale and they do not appear in consumer products. Of course there are food hydrocolloids, nano-particulate starch and other examples of commodities that could be considered as microgels – definitions are always controversial.

Trend 2 – Biodegradable Microgels: I suspect that the largest number of proposed microgel applications is biomedical, and most of those involve controlled drug release. For implanted microgels, biodegradability is an issue. In vivo decomposition requires that PNIPAM and other vinyl polymers must be replaced by polyesters, polyamides and other degradable backbones. In many cases biodegradability comes with the cost of losing the exquisite control of composition and particle size achievable with vinyl polymerization.

Trend 3 – Complex Functionalization: The original PNIPAM microgels offered little more than temperature sensitive swelling and a few sulfate or amidine groups. One can find microgel examples of all the popular forms of conjugation from biotinylation to click chemistry. Because microgels can be dialyzed, filtered, and centrifuged, purification and multi-step reactions are easier with microgels than with the corresponding soluble polymers. In most cases, the starting point for functionalization is the inclusion of carboxyls or amine groups in the parent microgels. With PNIPAM and related microgels, the topochemical distribution of these attachment points within the microgel particles is controlled by the polymerization kinetics.

Trend 4 – Organic/inorganic Composite Microgels: Magnetic microgels, quantum dot-loaded gels, and virtually any other nanoparticle-load microgel one can imagine has been reported. The synthesis either involves growing nanoparticles within the microgels or loading gels with existing particles. These systems should greatly expand the application space for microgels. Hellweg in Chapter 2 describes examples of composite microgels.

Trend 5 – Assembled Microgels: In my view, one of the most promising areas for microgels involves the assembly of microgels in much larger and complex structures. The early papers by Sandy Asher, Zhibing Hu and Andrew Lyon focused on exploiting the environmentally sensitive photonic properties of microgel based colloidal crystals. Microgels are readily printed by ink jet and other water-based printing technologies, facilitating roll-to-roll manufacturing of patterned surfaces. Surely the “killer application” is coming.

Microgel science is mature. With a thirty plus year history and the accumulated knowledge in hundreds of publications, it is possible to synthesize and characterize almost any microgel structure one could imagine. Nevertheless, there are some gaps. With the exception of neutron scattering, there are few (no?) tools to measure the mass and functional group distribution within microgel particles. Compared to our structural knowledge of proteins such as enzymes or other synthetic systems such as self-assembled monolayers, we know little about the detailed organization of microgels. Controlled radical polymerizations should give better control of microgel structure, facilitating characterization – see Matyjaszewski, Chapter 9.

The polymer reaction engineering aspects of microgels have received little attention. Hoare's work is the only significant kinetic modeling and there have been few measurements of microgel polymerization kinetics. Such work will be required to transform impractical academic microgel recipes (dilute solution, long reaction times, and purification by ultracentrifugation) into a commercial process when large scale applications emerge.

In closing, microgels are an established subset of the materials toolbox. The chapters herein describe fascinating phenomena that point to a multitude of potential applications. In my view, microgel science will not evolve as a separate field but will continue to occupy an important position in the hierarchy of nano-colloidal dispersed systems.

Robert PeltonMcMaster University

Preface

The idea of polymers, or more colloquially “plastics”, was initially met with scrutiny at the time of the initial experiments of Staudinger and Carothers. Despite this scrutiny, their ideas were eventually accepted, and these days one would be hard pressed to live one day (possibly one minute) without having contact with polymer-based materials. Whereas countless varieties of polymers, and polymer-based materials exist, this book focuses solely on colloidally stable hydrogel particles. Hydrogel particles, often referred to as microgels or nanogels depending on the length scale of their smallest dimension, are composed of a cross-linked hydrophilic polymer network. Because of the hydrophilicity of the polymer, and the cross-linked nature of the structure, the particles swell with water, typically taking on a spherical shape. Hydrogel particles have found their way into numerous applications ranging from lubricants in machinery to targeted/controlled drug delivery. Looking forward, there are still many potential applications that could benefit tremendously from new, enabling microgel-based materials. With the prospect of revolutionizing specific technologies, comes basic research; this book is meant to highlight the most exciting and impactful current research in the fields of microgels and nanogels. The volume was assembled to highlight the newest synthetic routes, characterization methods, and applications emergent in the area. Leaders in the field have contributed chapters representative of their most recent results from their respective labs, thereby shedding light on the enormous potential of this unique class of matter.

In editing this book the authors owe a great deal of thanks to our respective group members for volunteering their time to aid with the review process of the submitted chapters. We also owe a great deal of gratitude to Anja Tschörtner and Martin Preuss of Wiley for allowing us the opportunity to edit this volume, and for their assistance along the way.

L. Andrew LyonMichael J Serpe