Polymer Composites with Functionalized Nanoparticles

Synthesis, Properties, and Applications

Krzysztof Pielichowski, Tomasz M. Majka

• Publisher: Elsevier
• Year: 2018
• Print ISBN: 9780128140642
• eBook ISBN: 9780128140659
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Polymer Composites with Functional Nanoparticles: Synthesis, Properties, and Applications reviews the latest research in the area of polymer nanocomposites and functionalized nanoparticles, providing an introduction for those new to the field, and supporting further research and development. The book helps researchers and practitioners better understand the key role of nanoparticle functionalization for improving the compatibility of inorganic metallic nanomaterials with organic polymers, and for the fabrication of nanostructured materials with special properties. A range of nanoparticles, such as carbon nanotubes are covered, along with descriptions of the methods of functionalization to support better compatibility with polymer matrices.The book also discusses the various applications of this technology, including uses in electronics and the medical and energy industries.- Summarizes the latest research in functionalized nanoparticles for modification of polymer matrices, providing a valuable platform for further research- Includes functionalization of a range of nanoparticles for incorporation into nanocomposites, including carbon nanotubes, graphene, gold and silver, silica and clay- Provides detailed coverage of application areas, including energy, electronics, biomedical applications, and end-of-life considerations

1

Synthesis Routes of Functionalized Nanoparticles

Katarína Mosnáčková¹, Jozef Kollár¹, Yi-Shen Huang², Chih-Feng Huang² and Jaroslav Mosnáček^1,3, ¹Polymer Institute, Slovak Academy of Sciences, Bratislava, Slovakia, ²Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan, ³Centre for Advanced Materials Application, Slovak Academy of Sciences, Bratislava, Slovakia

Abstract

This contribution reviews synthetic approaches for functionalization of various nanoparticles (NPs) for tailoring their surface properties and improving wettability and compatibility with polymer matrices. The reactive functional groups required to be present in low molecular weight compounds and/or polymer chains are listed from the point of view of their ability to be attached onto the surface of various types of NPs. Three different methods of modification of NP surfaces by polymer chains are described in detail, separately for cationic, anionic, free radical as well as three main reversible deactivation radical polymerization techniques. Finally, examples of functionalization of modern types of NPs to obtain advanced properties of the nanocomposites are briefly presented.

Keywords

Grafting; living polymerization; reversible-deactivation radical polymerization; surface modification; metal nanoparticles; graphene; carbon nanotubes; compatibility; dispersibility; stimuli-responsive materials

Acknowledgment

This work was supported by the Slovak Academy of Sciences and the Ministry of Science and Technology, Taiwan through the joint project (SAS-MOST JRP 2014-9 and MOST 106-2923-E-194-001, respectively) entitled “Synthesis of well defined novel copolymers by use of living polymerization methods and advanced chromatography technique.” The authors also thank the Grant agency VEGA 2/0019/18, Slovak Research and Development Agency APVV through Grant APVV-15-0545 and APVV-14-0891, and Ministry of Science and Technology, Taiwan through project MOST 105-2628-E-005-003-MY3.

1.1 Introduction

Materials filled with nanoparticles (NPs) have attracted great interest due to their wide application in textiles, nanocomposites, biomedical and food industries, electronics, environment, and energy. Theoretically, Flory theories, density functional theories, and molecular dynamics methods can provide important directions thermodynamically and kinetically to predict the mixing stability of NPs and polymeric matrix. However, the precise calculations are still a challenge due to the difficulty in accessing the corresponding length and time scales [1–3]. To prepare materials with well-dispersed NPs for the practical applications, on the other prospect, surface functionalization is the key to stabilize NPs against aggregation in the polymer matrix. This chapter covers the functionalization of NPs surface with different functionalities and approaches. This process may provide several benefits such as improvement of NPs colloidal stability [4], their self-organization [5], compatibility with other phase [6,7], or incorporation of organic groups for specific interaction [8]. First, the surface modification includes simple functionalization of the NPs surface by low molecular weight compounds, which can directly improve stability and dispersibility of the NPs or can serve as introduction of functional groups needed for further postfunctionalization with low molecular weight compounds or polymers.

In the second part of this chapter the modification of NPs surface by polymers chains is reviewed. Controlled/living polymerizations [9–19], including ionic polymerizations, chain-growth condensation polymerization, and reversible-deactivation radical polymerizations (RDRPs), but partially also free radical polymerization (FRP) provide powerful tools for preparations of a variety of surface-functionalized NPs. Generally speaking, there are three major protocols for the surface functionalization, namely “grafting to,” “grafting from,” and “grafting through” methods. Accordingly, various polymerization techniques were successfully utilized for functionalization of NPs surface to improve the interfacial interactions between the NPs and polymeric matrices.

Due to the proper NPs dispersion, basic material properties can be improved and the final nanocomposites can be shifted toward various real-life applications with enhanced performance. The last part of this chapter is focused on the examples of specific properties and potential applications of the selected modern NPs, such as clays, Polyhedral Oligomeric Silsesquioxane (POSS), cellulose nanofibrils (CNFs), graphene, metal NPs, carbon nanotubes (CNTs), etc., functionalized by different strategies.

1.2 Functional Groups for Modification of Nanoparticles Surface

The common functionalization strategy can be defined as an addition of (new) chemical functionality on the surface of NPs. There are two main modification methods for attachment of a ligand and incorporation of functionality on NPs surface (Fig. 1–1). The first method involves direct functionalization with functional ligand containing one reactive group capable of attachment onto the NPs surface and the second one representing the required/targeted active surface functionality [20]. The second method consists of minimal two reaction steps. Initially, one reactive/functional group of bifunctional compound is reacted with NPs surface introducing a new functional group. Subsequently, the new functional group is used for postfunctionalization reaction to attach the ligand with required/targeted functionality on the NPs surface. Both strategies exhibit some advantages and limitations. Direct functionalization allows modification of NPs surface in one single step. On the other hand, in some cases a competitive reaction with functionality, which is going to be introduced on the NPs surface, can occur, and thus two-step modification needs to be applied. Another limitation of the direct functionalization approach relates with possible steric hindrance of the ligand, which can affect the surface grafting density. Postfunctionalization is a more versatile method and the main advantage of this technique is that plenty of coupling agents are commercially available [21].

Figure 1–1 Two methods of nanoparticle surface modification: (top) direct functionalization with ligand containing reactive group; (bottom) two-step modification consisting of initial functionalization of the nanoparticle surface and subsequent postfunctionalization.

Surface modification of NPs is generally realized during NPs synthesis in the presence of ligand, or in the case of prepared NPs by ligand exchange, ligand addition, formation of interdigitated layer, or by encapsulation. Ligand exchange technique is based on the point that the incoming ligand molecule binds more strongly to the inorganic NPs surface resulting in exchange of ligands [22,23]. The ligand addition method allows addition of ligand derivatives without removal of the original ligand [24]. Noncovalent interaction based on hydrophobic interaction between amphiphilic molecules or polymers leads to formation of an interdigitated bilayer [25,26]. Encapsulation can be generally accomplished by interaction of NPs stabilized with hydrophobic ligand with amphiphilic polymers [27].

1.2.1 Direct Functionalization of Nanoparticles Surface

1.2.1.1 Direct Functionalization of Noble Metals and Metal Oxides

Wide range of functional groups can be used for direct functionalization of NPs as depicted in Fig. 1–2. Modification of NPs surface by organosulfur derivatives is one of the most widely used and explored methods for noble metals, such as Au, Ag, Cu, Pt, etc. The surfaces of these metals exhibit strong affinity to thiols and disulfide groups. This chemisorption interaction leads to effective and quick surface modification or exchange of some other surfactants [28]. In addition, the concentration of organosulfur ligand can affect the size of NPs during their formation. Control over size of Au NPs from 2 to 5 nm was achieved by varying of dodecanethiol concentration [29]. Many authors reported the use of zwitterionic-based disulfide for stabilization of Au NPs. Resulting zwitterionic coated NPs provided sufficient colloidal stability in the pH region of 4–13 [30,31]. The character of the ligand determines overall properties of the NPs, especially the tendency to aggregate. Increased colloidal stability of Au NPs at higher tris–borate concentrations was obtained by modification of the Au NPs surface by mercaptopropionic acid [32].

Figure 1–2 Schematic illustration of functional groups for direct functionalization of nanoparticle surface.

Versatile route to stabilize NPs represents the addition of amine or ammonium containing ligands. Interaction between the amine groups and the surface of noble metal NPs is weaker as in the case of thiol groups, usually resulting in formation of larger NPs during the NPs preparation process. The spherical monodisperse magnetite NPs with the size around 5 nm can ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Preface
• 1. Synthesis Routes of Functionalized Nanoparticles
• 2. Design and Synthesis of Polymer Nanocomposites
• 3. Specific Interactions and Self-Organization in Polymer/Functionalized Nanoparticle Systems
• 4. Polymer Composites With Functionalized Silica
• 5. Functionalized Clay-Containing Composites
• 6. Functionalized POSS-Based Hybrid Composites
• 7. Polymer Composites with Functionalized Carbon Nanotube and Graphene
• 8. Polymer Composites With Metal Nanoparticles: Synthesis, Properties, and Applications
• 9. Polymer Nanocomposites With Decorated Metal Oxides
• 10. Optical Properties of Polymer Nanocomposites With Functionalized Nanoparticles
• 11. Organic Conjugated Polymer-Based Functional Nanohybrids: Synthesis Methods, Mechanisms and Its Applications in Electrochemical Energy Storage Supercapacitors and Solar Cells
• 12. Medical Applications of Polymer/Functionalized Nanoparticle Systems
• 13. Thermal Decomposition of Polymer Nanocomposites With Functionalized Nanoparticles
• 14. Polymer Composites Containing Functionalized Nanoparticles and the Environment
• 15. Future Perspectives
• Index