Ghimire Prateek; Yulin Wang; Henggan Li; Yuanfu Ban; Hao Luo; Danping Lin; Jinglong Yang; Shuyan Lin; Zhengyang Pan; Qingwei Su
Abstract
The purpose of this study is to analyse the effective method of dispersion of MWCNTs for the application in cement-based composites. Efficient dispersion of Carbon Nanotubes (CNTs) is one of the most challenging and crucial aspects for the application in cement-based composite. In this study, two different ...
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The purpose of this study is to analyse the effective method of dispersion of MWCNTs for the application in cement-based composites. Efficient dispersion of Carbon Nanotubes (CNTs) is one of the most challenging and crucial aspects for the application in cement-based composite. In this study, two different CNTs, pristine and functionalized (p-MWCNTs and f-MWCNTs) were dispersed in de-ionized water using different surfactants, Polyvinylpyrrolidone (PVP k-30 and PVP k-90) & Sodium Dodecyl Sulfate (SDS) and conducted a comparative investigation of the effects. Dispersion using an ultrasonic, treatment with surfactant and integrated method of both were analysed. The influence of CNTs dispersion on the electrical conductivity of the aqueous solution and to cement composites has been studied. Among the surfactant used PVPk-30 provide the best-dispersing effect while PVPk-30+SDS shows an extraordinary enhancement of conductivity of an aqueous solution. Analysis of electrical conductivity of Various % CNTs’ loaded specimen (0,0.001,0.003,0.025 wt.%) with different curing period (3,7,14,21,28 days) showed that the electrical resistivity decreases with CNTs’ loading. Dispersion effect of surfactant on p-MWCNTs and f-MWCNTs has been characterized by Ultraviolet-visible Spectroscopy (UV-Vis) and electrical resistivity measurement is carried for investigation and comparison on enhancement of electrical conductivity.
Naoki Komatsu
Abstract
Nanocarbons are carbon allotropes with nanometer scale and comprised mainly of 0 – 3 dimensional (0D – 3D) forms; fullerenes (0D), carbon nanotubes (1D), graphene (2D), and nanodiamond (3D). In our group, various surfactants with appropriate size and shape have been developed for the nanocarbons. ...
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Nanocarbons are carbon allotropes with nanometer scale and comprised mainly of 0 – 3 dimensional (0D – 3D) forms; fullerenes (0D), carbon nanotubes (1D), graphene (2D), and nanodiamond (3D). In our group, various surfactants with appropriate size and shape have been developed for the nanocarbons. In order to separate the fullerenes, bowl-shaped surfactants were designed and synthesized to accommodate the 0D spherical nanocarbon, giving C70 selectively as precipitates. On the other hand, gable- and bracket-shaped surfactants formed stable complexes with 1D tubular nanocarbons, dispersing carbon nanotubes with specific diameter, handedness and/or metallicity selectively in solution phase. The flat surfactants worked as an exfoliant and dispersant for graphite in both wet and dry processes; sonication and ball milling, respectively. They gave graphene composites with high concentrations and yield in aqueous solution and low-boiling point organic solvents. The hyper-branched polymer named polyglycerol coated the nanodiamond surface covalently through ring-opening polymerization of glycidol. The chemisorped polymer gave large hydrophilicity to the nanodiamond, dispersing it stably in aqueous solutions such as water and phosphate buffer as well as polar organic solvents such as methanol. Copyright © VBRI Press.
Chetna Verma; Poonam Negi; Deepak Pathania; Sadiya Anjum; Bhuvanesh Gupta
Abstract
Nanogel synthesis is gaining enormous interest in a large number of applications, such as drug delivery, wound care systems and tissue engineering. In the present work, we have investigated the preparation of Tragacanth gum (TG) nanoparticles in a water-in-oil nanoemulsion system. These nanoparticles ...
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Nanogel synthesis is gaining enormous interest in a large number of applications, such as drug delivery, wound care systems and tissue engineering. In the present work, we have investigated the preparation of Tragacanth gum (TG) nanoparticles in a water-in-oil nanoemulsion system. These nanoparticles exhibit stacked core-shell type of structure in which polygonal TG nanoparticles are covered by lipid structured lecithin (LC). The resultant nanoparticles comprise of amphillic nature, i.e. the hydrophilic TG core and hydrophobic LC shell which offers interesting features of immobilization of biomolecules.
Nadejda N. Begletsova; Oksana A. Shinkarenko; Ekaterina I. Selifonova; Olga Yu. Tsvetkova; Andrey M. Zakharevich; Rimma K. Chernova; Aleksey A. Kletsov; Evgeny G. Glukhovskoy
Abstract
In this paper a methodology of chemical synthesis of copper nanoparticles stabilized with surfactant cetylpyridinium chloride (CPC) micelles has been developed. By varying of the volume of a reduction agent hydrazine hydrate (HH) and value of pH of the reactionary environment the optimum conditions for ...
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In this paper a methodology of chemical synthesis of copper nanoparticles stabilized with surfactant cetylpyridinium chloride (CPC) micelles has been developed. By varying of the volume of a reduction agent hydrazine hydrate (HH) and value of pH of the reactionary environment the optimum conditions for synthesis of copper nanoparticles with a stable size ranging from 40 to 80 nm were found. The copper nanoparticles obtained by this methodology have a widely perspective for use in such fields as medicine, chemistry, electronics (Langmuir-Blodgett films with conductive properties). The synthesized copper nanoparticles were characterized by scanning electron microscopy (SEM) and UV-visible spectroscopy.
Sharda Sundaram Sanjay; Raghvendra S. Yadav; Avinash C. Pandey
Abstract
Lamellar porous ZnO has been synthesized at room temperature with the help of anionic surfactant SDS and characterized by XRD, SEM, TEM, PL, UV-Visible and FTIR spectroscopy. In the present investigation, SDS a peculiar surfactant act like a template and catalyses to the self-assembled growth of lamellar ...
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Lamellar porous ZnO has been synthesized at room temperature with the help of anionic surfactant SDS and characterized by XRD, SEM, TEM, PL, UV-Visible and FTIR spectroscopy. In the present investigation, SDS a peculiar surfactant act like a template and catalyses to the self-assembled growth of lamellar structure. Obtained structure is anisotropic lamellar in form with multiple secondary nucleation flaps growing perpendicular to a central lamina with uniform morphology. Photocatalytic activity of as synthesized ZnO on the degradation of bromophenol blue is also studied. The percentage of decolourization of dye was found 84.2% to 77.4% in first 30 min at 431 nm and 590 nm.
A. Santhana Krishna Kumar; S. Kalidhasan; Vidya Rajesh; N. Rajesh
Abstract
The microwave assisted preparation and characterization of chitosan-surfactant modified NaMMT clay composite material is discussed, followed by its interesting application to detoxify heavy metal chromium. Cr(VI) could be effectively adsorbed in a weakly acidic medium (pH 5) from a large sample volume. ...
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The microwave assisted preparation and characterization of chitosan-surfactant modified NaMMT clay composite material is discussed, followed by its interesting application to detoxify heavy metal chromium. Cr(VI) could be effectively adsorbed in a weakly acidic medium (pH 5) from a large sample volume. The composite material before and after the adsorption of chromium was scrupulously characterized using FT-IR, SEM, XRD and EDX techniques. The XRD study revealed the crystalline nature of the composite material with sharp and symmetric peaks. The bichromate ion forms an ion-pair with the protonated amine group in chitosan and this is reflected in the appearance of a Cr=O peak at 916 cm -1 in IR study. The surface hydroxyl groups in clay can be protonated and this could also serve as a source of electrostatic interaction with the bichromate oxyanion. The material exhibited a superior adsorption capacity of 133 mg g -1 and the adsorption data fitted well with Langmuir and Freundlich isotherm models. The composite adsorbent material exhibits a pore size of 3.5 nm at a maximum pore volume of 0.16 cm 3 g -1 . The BET surface area of the material obtained from N2 adsorption was found to be 52 m 2 g -1 . The experimental data also showed a good correspondence to the pseudo-second-order kinetics and the sorption thermodynamics correlated to the endothermic nature of the adsorption. The adsorbent could be regenerated using ascorbic acid or sodium sulfite which is indicative of the greener aspect in the methodology.