The precise quantification of the pyroelectric coefficient p is indispensable for the characterization of pyroelectric materials and the development of pyroelectric-based devices, such as radiation sensors or energy harvesters. A summary of the variety of techniques to measure p is given in the present review. It provides a classification after the thermal excitation and an outline of capabilities and drawbacks of the individual techniques. The main selection criteria are: the possibility to separate different contributions to the pyroelectric coefficient, to exclude thermally stimulated currents, the capability to measure p locally, and the requirement for metallic electrodes. This overview should enable the reader to choose the technique best suited for specific samples.
14 November 2014 in ACS Applied Materials & Interfaces
β-Chitinous scaffolds isolated from the skeleton of marine cephalopod Sepia officinalis were used as a template for the in vitro formation of ZnO under conditions (70 °C) which are extreme for biological materials. Novel β-chitin/ZnO film-like composites were prepared for the first time by hydrothermal synthesis, and were thoroughly characterized using numerous analytical methods including Raman spectroscopy, HR-TEM and XRD. We demonstrate the growth of hexagonal ZnO nanocrystals on the β-chitin substrate. Our chitin/ZnO composites presented in this work show antibacterial properties against Gram positive bacteria and can be employed for development of inorganic–organic wound dressing materials.
Chitinous scaffolds isolated from the skeleton of marine sponge Aplysina cauliformis were used as a template for the in vitro formation of zirconium dioxide nanophase from ammonium zirconium(IV) carbonate (AZC) under extreme conditions (150 °C). These novel zirconia–chitin based composites were prepared for the first time using hydrothermal synthesis, and were thoroughly characterized using a plethora of analytical methods. The thermostability of the chitinous 3D matrix makes it ideal for use in the hydrothermal synthesis of monoclinic nanostructured zirconium dioxide from precursors like AZC. These zirconium–chitin composites have a high potential for use in a broad range of applications ranging from synthetic catalysis to biocompatible materials for bone and dental repair. The synthetic methods presented in this work show an attractive route for producing monoclinic zirconium dioxide on a 3D biocompatible scaffold with ease.