GeoScienceWorld
Volume

Materials and Clay Minerals

Abstract

The one day workshop on which this volume was based focused on the development and use of advanced materials based on clays, and it was attended by well over 100 participants who were closely engaged with the speakers and participated in active question/answer and discussion sessions. The papers collected in this volume represent some of the most outstanding research presented at the workshop and each represents an exciting step forward in the development and integration of clay minerals into active and functional materials.

  1. Page 1
    Abstract
    Corresponding author (e-mail: makoto@waseda.jp)

    Photoactive species have been immobilized in the interlayer space and on the external surface of smectites to construct photofunctional hybrids. The spatial distribution (separation/distance) of photoactive species has been controlled by using smectites with different layer-charge density and by the co-adsorption of photoinactive species such as organoammonium ions and water-soluble polymers. As a result of controlled spatial distribution of photoactive species, the efficiency of photo-induced events (photoluminescence and photo-induced electron/energy transfer) has been altered.

  2. Page 21
    Abstract
    Corresponding author (e-mail: aranda@icmm.csic.es)

    Porous heterostructures based on clay minerals are of great importance, especially in developing nanoporous materials with pre-designed properties, e.g. so that they can be used as alternatives to zeolites (as catalysts). Pillaring strategies have been applied for many years to prepare conventional pillared clays (PILCs) and more recently clay heterostructures with modulated and larger porosity. Here, an overview of the diverse types of, and the main approaches developed to prepare, inorganic heterostructures based on clay minerals is given, from the classical PILCs to the most recent systems prepared by assembly of clay minerals and other inorganic solids. The state of the art in terms of strategies of synthesis, new trends, and applications beyond catalysis are described to highlight the many opportunities still available in this research area.

  3. Page 41
    Abstract
    Corresponding author (e-mail: hara@kicr.or.jp)

    Intelligent polymer hydrogels such as poly(N-isopropylacrylamide) (PNIPA) hydrogel, consisting of chemically cross-linked networks, have long been of interest but are mechanically fragile materials limited to specific uses. Important innovations have been made as a result of the creation of a novel class of nanocomposite (NC) hydrogels with a unique organic/inorganic network structure. The NC gels were synthesized by the in situ free-radical polymerization of N-alkylacrylamides in the presence of an inorganic clay mineral (hectorite). An organic (polymer)/inorganic (clay) network structure, consisting of exfoliated clay platelets uniformly dispersed in an aqueous medium with a number of flexible polymer chains linking them together, was formed uniformly throughout the sample. The NC gels exhibited high transparency, high degrees of swelling, and superb mechanical properties with extraordinarily large deformations of > 1000%. In addition, the NC gels formed from thermosensitive polymers, e.g. PNIPA, exhibited rapid transparency and gel volume (de-swelling) temperature responses at the transition temperature. These optical, mechanical, and swelling/ de-swelling properties could be controlled over a wide range by altering the gel composition and modifying the network structure. The NC gels could thus simultaneously overcome most of the traditional limitations of conventional polymer hydrogels. Furthermore, the NC gels exhibited a number of interesting new characteristics. These results indicate that NC gels hold promise as soft functional materials that can be utilized in various applications.

  4. Page 75
    Abstract
    Corresponding author (e-mail: rsuprakas@csir.co.za)

    Understanding the melt-state viscoelastic properties of clay-containing polymer nanocomposites (PCNs) is crucial to obtaining fundamental knowledge of the ‘processability’ and the structure-property relationship of these materials. In the case of PCNs, the melt-state viscoelastic properties are strongly influenced by their nanostructure. This chapter reviews recent advances in melt-state viscoelastic properties of PCNs. To begin this, brief descriptions of the structure and properties of clays, PCN processing, and thermodynamics are given. Attention is drawn to how viscoelastic behaviors of PCNs can be understood directly from their structure.

Purchase Chapters

Recommended Reading