**Nanocomposites of Polymers and Inorganic Nanoparticles**

Editor

**Walter Remo Caseri**

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*Editor* Walter Remo Caseri Vladimir-Prelog-Weg 5 Switzerland

*Editorial Office* MDPI St. Alban-Anlage 66 4052 Basel, Switzerland

This is a reprint of articles from the Special Issue published online in the open access journal *Nanomaterials* (ISSN 2079-4991) (available at: https://www.mdpi.com/journal/nanomaterials/ special issues/polymers inorganic nano).

For citation purposes, cite each article independently as indicated on the article page online and as indicated below:

LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. *Journal Name* **Year**, *Volume Number*, Page Range.

**ISBN 978-3-0365-0352-3 (Hbk) ISBN 978-3-0365-0353-0 (PDF)**

© 2021 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications.

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### **Contents**


Reprinted from: *Nanomaterials* **2019**, *9*, 956, doi:10.3390/nano9070956 ................ **105**


### **About the Editor**

**Walter Remo Caseri** studied chemistry at ETH Zurich, Switzerland, in 1983 and was ¨ subsequently educated as a Swiss radiation protection expert. Thereafter, he finished his Ph.D. in 1987 in the area of organometallic chemistry and catalysis. After a year at the Max Planck Institute for Polymer Research in Mainz, Germany, working in the area of the synthesis of inorganic polymers and their processing to ultrathin layers, he habilitated at the Institute of Polymers at ETH Zurich in the field of the synthesis and characterization of nanocomposites and chemistry at surfaces. Subsequently, he acted during 1993–1996 as leader of the Surface Protection Group at EMPA Dubendorf and thereafter joined ETH Z ¨ urich again, where he was awarded with the title of professor ¨ in 2006. He is active in the synthesis and investigation of materials of nanocomposites and polymers, surface chemistry and adhesion, and more recently also in the investigation of Roman concrete.

### **Preface to "Nanocomposites of Polymers and Inorganic Nanoparticles"**

This special issue is devoted to nanocomposites consisting of inorganic nanoparticles which are embedded in a polymer matrix. The collection of articles in this volume reflects the versatility of this class of nanocomposites. In fact, the diversity of both organic polymers and inorganic compounds suited for nanoparticles gives rise to the creation of a virtually indefinite number of nanocomposites with a broad spectrum of characteristics and applications. With regard to distinguished materials properties, often the inorganic component is in the focus, while the polymer acts as the matrix in which the nanoparticles are dispersed. The different nature of inorganic compounds applied for nanocomposites is clearly evident from the articles in this Special Issue, which include metals, metal oxides, metal sulfides, clays, hydroxyapatite, carbon nanotubes and graphene. The polymer matrix, on the other hand, can provide not only mechanical stability and processibility but also electrical conductivity and biocompatibility.

Nanocomposites have a history dating back more than 100 years, but they began to attract broader attention only in the early 1990s, which led to an ongoing boom. While initially the preparation of nanocomposites was in the foreground, the focus in the scientific literature has shifted more and more to material properties and potential applications, although innovative synthetic approaches are still being developed. All these aspects emerge in the articles of this Special Issue.

A key feature in nanocomposite preparation is the prevention of nanoparticle agglomeration or control of the arrangement of nanoparticles in the composite structure. This is of particular importance in the area of optics (cf. article by Pandit et al.) and superparamagnetism (cf. article by Gorka ´ et al.), as those properties are influenced by interparticle distances or clustering. While particle agglomeration in superparamagnetic nanocomposites is usually not desired, as this diminishes the superparamagnetic effect, on the other hand, particle agglomeration or controlled particle assembly can sometimes be used for specific changes in the optical behavior of a material. The prevention of particle agglomeration is especially difficult in nanocomposites with high particle contents since the probability that particles come into contact with each other increases with an increasing particle fraction. In such cases, agglomeration can be prevented by coating the surfaces of the particles, which has also been applied with a view to nanocomposites with enhanced dielectric and mechanical properties (cf. article by You et al. and Hornak et al.).

As already indicated above, the variety of properties of nanocomposites offers possibilities for applications in a variety of areas. With regard to the usage of nanocomposites for chemical reactions, catalysis attracts attention since a number of nanoparticles can act as catalytically active centers, as demonstrated in this Special Issue by a model system for the reduction of 4-nitrophenol (cf. article by Harrison et al.) and for the decomposition of hydrogen peroxide in the context of cleaning contact lenses (cf. article by Ohkubo et al.). Moreover, particular physical properties promote the deployment of nanocomposites in technical fields, such as gas barriers (cf. article by Chang), optics (e.g., materials with high refractive index, cf. article by Takafuji et al.), corrosion protection (cf. article by Qu et al.), electromagnetic inference (EMI) shielding (cf. article by Raagular et al.) and lithium ion batteries (cf. article by Caimi et al.), as well as in the area of biomedicine, such as tissue engineering (cf. article by Ribeiro et al.) and plastic surgery (cf. article by Lin et al.). Accordingly, it is evident that the area of composites of polymers and inorganic nanoparticles is of vital interest in various disciplines, particularly chemistry, physics, biomedicine and materials science, and that such nanocomposites are a focal point for innovative science and a source of inspiration for currently relevant economic topics as well as for envisaged technologies of the future.

> **Walter Remo Caseri** *Editor*

*Article*
