Durable superhydrophobic ZnO-SiO2 films: a new approach to enhance the abrasion resistant property of trimethylsilyl functionalized SiO2 nanoparticles on glass

Although trimethylsilyl functionalized SiO2 derived films show excellent superhydrophobicity, their adhesion and abrasion resistant properties are extremely poor. In this study, a new approach has been shown to improve the adhesion and abrasion properties of such films. A neutral and relatively hydrophobic Zn(CH3OO)(2)(H2O)(2)] complex solution has been used to interact with the superhydrophobic silica gel nanoparticle dispersion. After dip-coating, the composite sol yielded films of a zinc acetate/superhydrophobic silica composite network while the hydrophilic part (bonded water) associated with Zn helps in binding the hydroxyl groups (silanols) present on the glass surface. The composite films were heat-treated at 300-400 degrees C in a nitrogen atmosphere in order to obtain transparent and superhydrophobic ZnO-SiO2 nanocomposite films. The decomposition of zinc acetate formed ZnO nanocrystallites and remained attached with the hybrid silica matrix. These films showed excellent water repellency (water contact angle, CA approximate to 158 +/- 7 degrees; hysteresis approximate to 4 degrees) with good adhesion and abrasion resistant properties. XRD, Raman and TEM studies confirm the existence of ZnO nanocrystallites in the composite films. Owing to the stability of hydrophobic methyl groups attached with silicon at relatively high temperature in a nitrogen atmosphere, these ZnO-SiO2 nanocomposite films remain superhydrophobic even after a heat-treatment at 400 degrees C

A Novel Triterpenoid Isolated from the Root Bark of Ailanthus excelsa Roxb (Tree of Heaven), AECHL-1 as a Potential Anti-Cancer Agent

We report here the isolation and characterization of a new compound Ailanthus excelsa chloroform extract-1 (AECHL-1) (C(29)H(36)O(10); molecular weight 543.8) from the root bark of Ailanthus excelsa Roxb. The compound possesses anti-cancer activity against a variety of cancer cell lines of different origin.AECHL-1 treatment for 12 to 48 hr inhibited cell proliferation and induced death in B16F10, MDA-MB-231, MCF-7, and PC3 cells with minimum growth inhibition in normal HEK 293. The antitumor effect of AECHL-1 was comparable with that of the conventional antitumor drugs paclitaxel and cisplatin. AECHL-1-induced growth inhibition was associated with S/G(2)-M arrests in MDA-MB-231, MCF-7, and PC3 cells and a G(1) arrest in B16F10 cells. We observed microtubule disruption in MCF-7 cells treated with AECHL-1 in vitro. Compared with control, subcutaneous injection of AECHL-1 to the sites of tumor of mouse melanoma B16F10 implanted in C57BL/6 mice and human breast cancer MCF-7 cells in athymic nude mice resulted in significant decrease in tumor volume. In B16F10 tumors, AECHL-1 at 50 microg/mouse/day dose for 15 days resulted in increased expression of tumor suppressor proteins P53/p21, reduction in the expression of the oncogene c-Myc, and downregulation of cyclin D1 and cdk4. Additionally, AECHL-1 treatment resulted in the phosphorylation of p53 at serine 15 in B16F10 tumors, which seems to exhibit p53-dependent growth inhibitory responses.The present data demonstrate the activity of a triterpenoid AECHL-1 which possess a broad spectrum of activity against cancer cells. We propose here that AECHL-1 is a futuristic anti-cancer drug whose therapeutic potential needs to be widely explored for chemotherapy against cancer

Stable fluorescent CdS:Cu QDs and their hybridization with carbon polymer dots for white light emission

A simply-processed, stable colloidal white light emission, obtained by hybridizing the orange emitting copper doped CdS (CdS:Cu) and cyan emitting carbon polymer dots (CPDs) as a donor-acceptor pair is described. The chromaticity colour coordinates of the obtained white light were (0.32, 0.33). To achieve this, we formulated a new approach for synthesizing stable CdS: Cu QDs in non-coordinating mixed solvents, without using additional capping agents. The CPDs were synthesized by the controlled decomposition of branched polyethylenimine, followed by purification. Finally, proportionate amounts of orange emitting CdS: Cu and CPD dispersion were used to produce white light emission. We further stabilised the colloidal white light emission in organically modified SiO2 (ORMOSIL) sol, which can be used as fluorescent paint, and to deposit durable coatings on glass substrates. The coated films show very good PL stability when stored under ambient conditions and under UV (365 nm) light

Design of mesoporous alumina-ceria films on glass: Compositional tuning leads to mesoscopic transformations

We report the first synthesis of 3D ordered cubic mesoporous alumina-ceria films on glass using the triblock copolymer F127 as a structure directing agent. Aluminium tri-sec-butoxide partially chelated with acetyl acetone and cerium nitrate were used as alumina and ceria precursors, respectively, and the concentration of ceria in alumina was varied from 0 (pure Al) to 100 (pure Ce) mol%. Symmetry of mesopores and structural morphologies were tuned simply by alumina/ceria compositional control. The mesophase transformation from cubic Im (3) over barm to Ia3d symmetries occurred when the concentration of cerium nitrate was increased from 0-1 mol% to 5-8 mol%; while higher ceria loadings resulted in the formation of phase segregated alumina-rich spheres embedded in a ceria-rich matrix. The mechanism of the evolution of mesoscopic transformations were established by transmission SAXS studies of the alumina-ceria sols and GIXRD, FESEM, TEM, FTIR and Raman analysis of the films. The crystalline nature of alumina-ceria films with respect to different ceria loadings heat-treated at 400 and 800 degrees C were also reported. (C) 2014 Elsevier Inc. All rights reserved

Stable Ni Nanoparticle–Reduced Graphene Oxide Composites for the Reduction of Highly Toxic Aqueous Cr(VI) at Room Temperature

Inherent properties of graphene can be experienced by integrating it with different nanomaterials to form unique composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP–reduced graphene oxide (Ni–RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr­(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni–RGO by introducing an intermediate redox step with formic acid. The Ni–RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni–RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature

Single-step in-situ synthesis and optical properties of ZnSe nanostructured dielectric nanocomposites

This work provides the evidence of visible red photoluminescent light emission from ZnSe nanocrystals (NCs) grown within a dielectric (borosilicate glass) matrix synthesized by a single step in-situ technique for the first time and the NC sizes were controlled by varying only the concentration of ZnSe in glass matrix. The ZnSe NCs were investigated by UV-Vis optical absorption spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM). The sizes of the ZnSe NCs estimated from the TEM images are found to alter in the range of 2-53 nm. Their smaller sizes of the NCs were also calculated by using the optical absorption spectra and the effective mass approximation model. The band gap enlargements both for carrier and exciton confinements were evaluated and found to be changed in the range of 0-1.0 eV. The Raman spectroscopic studies showed blue shifted Raman peaks of ZnSe at 295 and 315 cm(-1) indicating phonon confinement effect as well as compressive stress effect on the surface atoms of the NCs. Red photoluminescence in ZnSe-glass nanocomposite reveals a broad multiple-peak structure due to overlapping of emission from NC size related electron-hole recombination (similar to 707 nm) and emissions from defects to traps, which were formed due to Se and Zn vacancies signifying potential application in photonics. (C) 2014 AIP Publishing LLC

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-