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Applied Nanoscience (v.1, #3)

Functional role of cationic surfactant to control the nano size of silica powder by L. P. Singh; S. K. Bhattacharyya; G. Mishra; S. Ahalawat (pp. 117-122).

Preparation of dispersed, amorphous, spherical silica nanoparticles using cationic surfactant as organic template, tetraethoxysilane (TEOS) as silica precursor and ammonia as catalyst has been carried out using sol gel process. The aim of the present study was to evaluate the simultaneous effects of cationic surfactant on the textural and structural properties of silica nanoparticles. We used a series of the cationic surfactants, dodecytrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) and cetyltrimethylammonium bromide (CTAB) to evaluate the effects of the chain length of cationic surfactant on the grain size of silica nanoparticles. The size of silica nanoparticles can be finely tuned in the range ~50–100 nm by changing the chain length of cationic surfactant. Decreasing the particle size of silica nano particles resulted in increase in chain length of cationic surfactant. Further, these silica nanoparticles are incorporated with cement paste to evaluate the beneficial effect on mechanical properties of cement. Synthesized silica nanoparticles were analyzed using scanning electron microscopy (SEM), ²⁹Si MAS NMR, powder X-ray diffraction techniques (XRD) and IR studies.

Keywords: Sol gel; Cationic surfactant; Silica nanoparticles; 29Si MAS-NMR; Calcium leaching

Optimization of annealing to decrease quantity of radiation defects in a bipolar transistor by E. L. Pankratov (pp. 123-129).

It has recently been shown that manufacturing of diffusive- and implanted-junction bipolar transistors in semiconductor heterostructure and optimization of annealing give us possibility to increase compactness of dopant distributions. In this paper, we analyze the possibility of decreasing the quantity of radiation defects by choosing regimes of annealing.

Keywords: Implanted-junction rectifiers; Optimization of manufactoring of rectifiers; Decreasing of quantity of radiation defects

Synthesis of kaolinite-filled EPDM rubber composites by solution intercalation: structural characterization and studies on mechanical properties by S. Ginil Mon; Y. Jaya Vinse Ruban; D. Vetha Roy (pp. 131-135).

In the large field of nanotechnology, polymer matrix-based nanocomposites have become a prominent area of current research and development. Exfoliated clay-based nanocomposites have dominated the polymer world with excellent characteristics. EPDM rubber composites have been synthesized by solution-intercalation using the easily available kaolinite as filler. The composite structure has been elucidated by X-ray diffraction (XRD), Fourier transform IR, and scanning electron microscope studies. The molecular level dispersion of clay layers has been verified by the disappearance of basal XRD peak of kaolinite in the EPDM/kaolinite composites. The mechanical properties showed significant improvement of EPDM/kaolinite composites with respect to neat EPDM.

Keywords: EPDM; Kaolinite; Solution-intercalation; Morphology; Mechanical properties

Effect of Gum arabic on distribution behavior of nanocellulose fillers in starch film by Nadanathangam Vigneshwaran; L. Ammayappan; Qingrong Huang (pp. 137-142).

Uniform distribution of nanofillers in polymer matrix is posing a major challenge in exploiting the full potential of nanomaterials. Various fillers are being evaluated to improve the performance of biopolymer films like starch. In this work, nanocellulose is used as fillers to increase the performance characteristics of starch film. Due to high surface energy and hydrophilic nature of nanocellulose, they tend to aggregate during the film forming process. To circumvent this problem, Gum arabic (GA) was added to distribute the nanocellulose uniformly. GA helps in reduction of surface energy (as analyzed by contact angle) and thus facilitates the uniform distribution of nanocellulose (as demonstrated through polarized light microscopy). Nanocellulose as filler improved the tensile strength of starch film by 2.5 times while that of uniformly distributed nanocellulose by 3.5 times. Moreover, while nanocellulose as such could reduce the water vapor permeability of starch film by 1.4 times, uniformly distributed nanocellulose reduced it by 2 times proving the importance of GA. Starch film filled with nanocellulose and GA will be a 100% biopolymer-based system having potential demand in eco-friendly applications.

Keywords: Atomic force microscopy; Gum arabic; Nanocellulose; Nanocomposites; Polarized microscopy; Surface energy

A memristor-based third-order oscillator: beyond oscillation by A. Talukdar; A. G. Radwan; K. N. Salama (pp. 143-145).

This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

Keywords: Memristor; Linear time variant; Oscillator

Photocatalytic degradation of Chromium (VI) from wastewater using nanomaterials like TiO₂, ZnO, and CdS by K. M. Joshi; V. S. Shrivastava (pp. 147-155).

The photocatalytic degradation of Cr(VI) from wastewater by using nanomaterials TiO₂, ZnO, and CdS. All the experiments were carried out in the batch process. The wastewater obtained from various industries. The amount of chromium was removed using photocatalyst with UV light and in the dark at different pH range. The maximum removal of Cr(VI) was observed at pH 2; out of these photocatalyst TiO₂ showed highest capacity for Cr(VI) removal than TiO₂ thin film. The removal of chromium has been studied by considering influent concentration, loading of photocatalyst, pH, and contact time as operating variables. The degradation was characterized by FTIR, XRD, SEM, and EDX analysis before and after application of photocatalysts.

Keywords: Photocatalysis; Sol–gel thin film; FTIR; XRD; SEM; EDX

Effect of the chemical composition at the memory behavior of Al/BST/SiO₂/Si-gate-FET structure by Ala’eddin A. Saif; Z. A. Z. Jamal; P. Poopalan (pp. 157-162).

The effect of the chemical composition of the ferroelectric barium strontium titanate (BST) on the memory window behavior of Al/BST/SiO₂/Si-gate-field effect transistor structure has been investigated. Nanocrystalline Ba xSr1−xTiO₃ thin films with different x values have been fabricated as metal-ferroelectric-insulator-semiconductor (MFIS) and metal-ferroelectric-metal (MFM) configurations using a sol–gel technique. The variation of the dielectric constant (ε) and tan δ with frequency for MFM samples have been studied to ensure the dielectric quality of the material. At low frequencies, ε increases as the strontium content decreases, whereas at high frequencies, it shows the opposite variation, which is attributed to the dipole dynamics. The ferroelectricity of the BST within MFM structure has been investigated using C–V characteristics, which show that the ferroelectric hysteresis strength increases as the strontium content decreases. The ferroelectric memory behavior of the MFIS samples has been investigated using C–V characteristics. The results show that the memory window width increases as the strontium content decreases; this is attributed to the grain size and dipole dynamics effect.

Keywords: BST thin films; Dielectric properties; Ferroelectric hysteresis; Memory window; MFIS-FET

Erratum to: Functional role of cationic surfactant to control the nano size of silica powder by L. P. Singh; S. K. Bhattacharyya; G. Mishra; S. Ahalawat (pp. 163-163).

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Applied Nanoscience (v.1, #3)

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Applied Nanoscience (v.1, #3)