Smart Polymers and Their Applications

Maria Rosa Aguilar, Julio San Román

• Publisher: Woodhead Publishing
• Year: 2019
• ISBN:
  9780081024171
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Smart Polymers and Their Applications, Second Edition presents an up-to-date resource of information on the synthesis and properties of different types of smart polymers, including temperature, pH, electro, magnetic and photo-responsive polymers, amongst others. It is an ideal introduction to this field, as well as a review of the latest research in this area. Shape memory polymers, smart polymer hydrogels, and self-healing polymer systems are also explored. In addition, a very strong focus on applications of smart polymers is included for tissue engineering, smart polymer nanocarriers for drug delivery, and the use of smart polymers in medical devices.

Additionally, the book covers the use of smart polymers for textile applications, packaging, energy storage, optical data storage, environmental protection, and more. This book is an ideal, technical resource for chemists, chemical engineers, materials scientists, mechanical engineers and other professionals in a range of industries.

• Includes a significant number of new chapters on smart polymer materials development, as well as new applications development in energy storage, sensors and devices, and environmental protection
• Provides a multidisciplinary approach to the development of responsive polymers, approaching the subject by the different types of polymer (e.g. temperature-responsive) and its range of applications

Chapter 1

Introduction to Smart Polymers and Their Applications

María Rosa Aguilar^⁎,†; Julio San Román^{⁎,† ⁎} Group of Biomaterials, Department of Polymeric Nanomaterials and Biomaterials, Institute of Polymer Science and Technology, (ICTP-CSIC), Madrid, Spain
^† Networking Biomedical Research Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain

Abstract

The scientific community tries to mimic nature because living organisms accommodate their behavior as a function of environmental conditions to improve survival. In this sense, smart polymers offer materials that respond to numerous stimuli (e.g., temperature, pH, electric and magnetic fields, light intensity, biological molecules), and scientists must devise the best ways to apply them in all research areas. This chapter comprehensively summarizes the content of this book, which tries to provide a wide updated overview of smart polymers and their most interesting recently developed applications.

Keywords

Polymers; Enzyme; Living systems; Hydrogel; Biomaterials

Acknowledgment

The authors greatly acknowledge the financial support from MAT2017-84277-R project.

Living systems respond to environmental conditions to accommodate their structure and functionality to variations in nature via the action of complex sensing mechanisms, actuating and regulating functions, and feedback control systems. Therefore, nature can be considered the best example a scientist can have in mind when developing new materials and applications; the overall challenge is to create materials with dynamic and tunable properties that mimic the active microenvironment that occurs in nature.

Smart polymers or stimuli-responsive polymers undergo reversible, large, physical or chemical changes in their properties as a consequence of small environmental variations. They can respond to a single or multiple stimuli such as temperature, pH, electric or magnetic fields, light intensity, biological molecules, etc. that induce macroscopic responses in the material, such as swelling, collapse, or solution-to-gel transitions, depending on the physical state of the chains (Aguilar et al., 2007). Linear and solubilized smart macromolecules will pass from monophasic to biphasic near the transition conditions giving rise to reversible sol-gel states. Smart cross-linked networks undergo chain reorganization at transition conditions where the network passes from a collapsed to an expanded state. Smart surfaces change its hydrophilicity as a function of a stimulus providing responsive interfaces. All these changes can be used in the design of smart devices for multiple applications, for example, minimally invasive injectable systems (Nguyen and Lee, 2010), pulsatile drug delivery systems (Tran et al., 2013; Arora et al., 2011), or new substrates for cell cultures or tissue engineering (Duarte et al., 2011).

Moreover, most polymers can be easily functionalized by prepolymerization (Guillerm et al., 2012) or postpolymerization (Arnold et al., 2012) methods incorporating functional molecules to the structure, such as biological receptors (Shakya et al., 2010). Therefore, polymer scientists have a wide range of possibilities in terms of polymer chemical structures, polymer architectures, and polymer modifications to develop an infinite number of applications with these smart materials (Stuart et al., 2010).

The aim of this new edition of Smart Polymers and Their Applications is not only to guide the reader through the state-of-the-art in this area but also shed some light on future research directions in this research field. The first part of the book (Chapters 2 to 11) gives the reader a wide overview about different stimuli-responsive polymers. Temperature, pH, light intensity, conductive and electroactive-responsive polymers, metabolite and enzyme-responsive polymers, and inflammation-responsive polymers are described. Moreover, due to their actual and future applications, special attention was paid to smart protein fibers, smart hydrogels, and self-healing polymers.

1.1 Types of Smart Polymers

Temperature-sensitive polymers present low critical solution temperature (LCST) or upper critical solution temperature (UCST) depending on their transition behavior from monophasic to biphasic when temperature is raised or, on the contrary, from biphasic to monophasic when temperature is raised, respectively. LSCT polymers have been widely investigated, whereas UCST polymers are quite rare. Most common LCST polymers are the poly(N-substituted acrylamide), poly(vinyl amide), and poly(oligoethylene glycol (meth)acrylate) families. However, many other polymers can present LCST if the proper hydrophilic-hydrophobic balance is present in the macromolecules. Poly(vinyl ether)s (Aoshima and Kanaoka, 2008), poly(2-oxazoline)s (Guillerm et al., 2012), and poly(phosphoester)s (Wang et al., 2009) also present temperature-responsive behavior and are specifically described in Chapter 2. Moreover, the three main classes of T-responsive polymers are also reviewed, that is, shape-memory materials (Löwenberg et al., 2017), liquid-crystaline materials (Ober and Weiss, 1990), and responsive polymer solutions (Hoffman, 2013). Polymers that respond to temperature changes and, more specifically, those that undergo a phase transition in water solution are gaining special attention due to their potential applications in the biomaterials field (Bajpai et al., 2010), architecture (Yang et al., 2013; Rotzetter et al., 2012), or water-recovery strategies (Yang et al., 2013), among others.

pH-sensitive polymers bear weak polyacidic (poly(acrylic acids) or poly(methacrylic acids)) or polybasic (poly(N-dimethylaminoethyl methacrylate), poly(N-diethylaminoethyl methacrylate), or poly(ethyl pyrrolidine methacrylate)) moieties in their structure that protonate or deprotonate as a function of the surrounding pH. Personal care, biomedical field (Yu et al., 2017), industrial processes (Kan et al., 2013), and water remediation (Wang et al., 2016) are some of the multiple areas of application described for this kind of smart polymer.

Photosensitive polymers undergo a reversible or irreversible change in conformation, polarity, amphiphilicity, charge, optical chirality, or conjugation in response to a light stimulus. Reversible chromophores or reversible molecular switches (e.g., azobenzenes, spiropyran, diaryl ethane, or coumarin) undergo a reversible isomerization upon light irradiation (Wang and Wang, 2013) whereas irreversible chromophores are cleaved from the polymer chain upon light exposure (e.g., ο-nitrobenzyl photolabile protecting group) or induced reactivity resulting in the coupling of two species (e.g., 2-naphtoquinone-3-methides). Both molecular switches and irreversible chromophores have been applied in multiple applications such as drug delivery systems, functional micropatterns, responsive hydrogels, photodegradable materials, or photoswitchable liquid crystalline elastomers for remote actuation (Ohm et al., 2010).

Intrinsically conductive polymers are organic polymers that conduct electricity. Chapter 7 focuses on conductive polymers for bioelectronics, that is, the interface between electronics and biology. Poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives PEDOT:poly(styrene sulfate) (PEDOT:PSS), PEDOT:biopolymer, and poly(3,4-Propylenedioxythiophene) (ProDOT) and its derivatives are most successful in bioelectronics and have been used as electrodes for electrophysiology, organic chemical transistors (OECTs), organic electronic ion-pump (OEIP), electronic textiles, and electronic skin (Simon et al., 2016).

Peptides can be rationally designed by chemical or biotechnological procedures to assemble into different shapes (e.g., fibers, spheres, tubes) as a result of specific stimuli. Chapter 9 reviews stimuli-responsive protein fibers for their application as sensors (Liu et al., 1996). Moreover, their bioapplications ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Chapter 1: Introduction to Smart Polymers and Their Applications
• Chapter 2: Temperature-Responsive Polymers: Properties, Synthesis, and Applications
• Chapter 3: pH-Responsive Polymers: Properties, Synthesis, and Applications
• Chapter 4: Photoresponsive Polymers
• Chapter 5: Enzyme-Responsive Polymers: Classifications, Properties, Synthesis Strategies, and Applications
• Chapter 6: Conductive Poly(3,4-Ethylenedioxythiophene) (PEDOT)-Based Polymers and Their Applications in Bioelectronics
• Chapter 7: Inflammation-Responsive Polymers
• Chapter 8: Dual- and Multistimuli-Responsive Polymers for Biomedical Applications
• Chapter 9: Smart Polymer Gels: Properties, Synthesis, and Applications
• Chapter 10: Stimuli-Responsive Protein Fibers for Advanced Applications
• Chapter 11: Self-Healing Polymeric Systems: Concepts and Applications
• Chapter 12: Smart Instructive Polymer Substrates for Tissue Engineering
• Chapter 13: Smart Polymeric Nanocarriers for Drug Delivery
• Chapter 14: The Use of Smart Polymers in Medical Devices for Minimally Invasive Surgery, Diagnosis, and Other Applications
• Chapter 15: Smart Polymers for Bioseparation and Other Biotechnological Applications
• Chapter 16: Smart Polymers for Optical Data Storage
• Chapter 17: Smart Polymers for Highly Sensitive Sensors and Devices: Micro- and Nanofabrication Alternatives
• Chapter 18: Toward Smart Polymeric Binders for Battery Electrodes
• Index