Journal•ISSN: 0976-3961
Advanced Materials Letters
International Association of Advanced Materials
About: Advanced Materials Letters is an academic journal published by International Association of Advanced Materials. The journal publishes majorly in the area(s): Dielectric & Thin film. It has an ISSN identifier of 0976-3961. Over the lifetime, 1226 publications have been published receiving 13449 citations.
Topics: Dielectric, Thin film, Smart material, Nanoparticle, Nanocomposite
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TL;DR: Though there is ample of research related to carboxymethyl chitosan (CMC), the focused review of the topic is unavailable, an attempt is made to cover the recent findings pertaining to synthesis, characterization, and its applications especially in pharmaceutical field.
Abstract: Deacetylation of chitin affords chitosan, a polymer, widely studied for its pharmaceutical and nonpharmaceutical applications. The hurdle in comprehending these applications is its limited solubility. Carboxymethylation of chitosan helps to surmount this hurdle with its improved solubility in water. Though there is ample of research related to carboxymethyl chitosan (CMC) the focused review of the topic is unavailable. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization of CMC and its applications especially in pharmaceutical field. CMC has been synthesized by ways as direct alkylation, reductive alkylation, Michael addition and characterized by FTIR, NMR spectroscopy, and DSC, titrimetry, viscometry, gel permeation chromatography, X-ray diffraction and capillary zone electrophoresis. The carboxymethyl group can be present at O or N or both the atoms of chitosan molecule. The CMC possess modulated physical and biological properties as chelating, sorption, moisture retention, cell functioning antioxidant, antibacterial, antiapoptotic etc. CMC is used in sustained or controlled release drug delivery, pH responsive drug delivery, DNA delivery as permeation enhancer etc. CMC can be further modified with alkylation, acylation, and grafting. Carboxyalkylation of chitosan yield carboxyethyl, carboxybutyl chitosans. These analogues of CMC may be helpful in substantiating the applications of chitosan. Copyright © 2010 VBRI press.
381 citations
TL;DR: In this article, a biological approach for the formation of zinc oxide (ZnO) nanoparticles using Maddar (Calotropis procera) latex at room temperature is reported.
Abstract: Herein, we are reporting a novel biological approach for the formation of zinc oxide (ZnO) nanoparticles using Maddar (Calotropis procera) latex at room temperature. X-Ray diffraction (XRD) pattern reveals the formation of ZnO nanoparticles, which shows crystallinity. Transmission electron microscopy (TEM) suggested particles size and shape in the range of 5-40 nm. Scanning electron microscopy (SEM) image reveals that the particles are of spherical and granular nature. UV-Vis absorption shows characteristic absorption peak of ZnO nanoparticles. Photoluminescence (PL) studies were performed to emphasize its emission properties. This simple and cost-effective biological approach for the formation of ZnO NPs has a promising application in biosensing, electronics and photonics. Copyright © 2011 VBRI press.
232 citations
TL;DR: In this article, the effect of broth concentration in reduction mechanism and particle size was investigated and it was found that increasing broth concentration increases the rate of reduction and decreases the particle size.
Abstract: Biological synthesis of silver nanoparticles using Murraya koenigii leaf extract was investigated and the effect of broth concentration in reduction mechanism and particle size is reported. The rapid reduction of silver (Ag + ) ions was monitored using UV-visible spectrophotometry and showed formation of silver nanoparticles within 15 minutes. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) analysis showed that the synthesized silver nanoparticle are varied from 10-25 nm and have the spherical shape. Further the XRD analysis confirms the nanocrystalline phase of silver with FCC crystal structure. From this study, it was found that the increasing broth concentration increases the rate of reduction and decreases the particle size. Copyright © 2011 VBRI press.
186 citations
TL;DR: In this paper, the effect of aniline concentrations on the growth and size of silver nanoparticles using anilines and silver nitrate as reductant and oxidant, respectively, was reported.
Abstract: In this paper we report the effect of aniline concentrations on the growth and size of silver nanocrystals using aniline and silver nitrate as reductant and oxidant, respectively. UV-Vis spectroscopy, transmission electron microscopy (TEM) and selected areas electron diffraction (SAED) have been employed to characterize silver nanoparticles. The TEM images show that silver nanocrystals are roughly spherical and of uniform particle size, and the average particle size is ca. 25 nm. A broad surface plasmon resonance band appears at 400 nm. The rings patterns are in good agreement with the standard values of the facecentered-cubic form of silver nanocrystals. This is attributed to the adsorption of aniline and /or interparticle interaction onto the surface of Ag-nanocrystals through electrostatic interactions between the lone-pairs electrons of –NH2 and positive surface of Ag- nanoparticles. Copyright © 2011 VBRI press.
142 citations
TL;DR: A review of thermochromism in solid-state materials is presented in this article, with a focus on vanadium (IV) oxide since its transition temperature is closest to room temperature and the possibility of fine-tuning the transition temperature by introducing various dopants into the vanadium oxide lattice.
Abstract: Solid-state thermochromic materials undergo semiconductor to metal transitions at a 'critical temperature', Tc. This review begins by describing the phenomenon of thermochromism, whereby the optical properties of a material change reversibly as a result of a change in temperature. The various different types of thermochromism will be introduced with a focus on the thermochromism exhibited by solid-state materials. The fundamental chemical principles that describe the electronic structure and properties of solids, and the chronological developments in the theory behind the thermochromic transitions (such as, the effects of electron-electron interactions and structural phase changes due to lattice distortions) that led to the discovery of the semiconductor-to-metal transition, are presented. An extensive discussion of vanadium and titanium oxides is presented with a particular focus on vanadium (IV) oxide since its transition temperature is closest to room temperature. Observations and current understanding of the nature of the semiconductor-to-metal transition exhibited by these materials is detailed. The possibility of fine-tuning the transition temperature by introducing various dopants into the vanadium (IV) oxide lattice is examined and the effects of dopant charge and size is examined. Solid-state thermochromic materials may be exploited in areas such as microelectronics, data storage, or intelligent architectural glazing, thus are required to be synthesised as thin films for use in such applications. The numerous synthetic techniques (PVD, sol-gel method, PLD, CVD, APCVD and AACVD), for making metal oxide thermochromic thin films are described in reference to the production of vanadium (IV) oxide and compared. Finally rare earth nickelates exhibiting thermochromism are described. Copyright © 2010 VBRI press.
127 citations