We have demonstrated that the gel-like mesophase of Cetyltrimethylammonium bromide (CTAB) can be synthesized by judicial adjustment of water to surfactant molar ratio (W0), without using any additional salts, gelating agents or co-surfactants. Gel formation was found to be highly dependent on the water to surfactant molar ratio (W0), with the lowest value of W0 (41.5) resulting in rapid gel formation. Environmental scanning electron microscope (ESEM) analysis revealed that the gel was comprised of interconnected cylindrical structures. The presence of hydrogen bonding in the gel-like mesophase was confirmed by Fourier Transform Infrared spectroscopy (FTIR) analysis. Rheology measurements revealed that all the gel samples were highly viscoelastic in nature. Furthermore, Au and Ag containing CTAB gels were explored as precursors for the preparation of spherical Gold (Au) and Silver (Ag) nanoparticles using Sodium borohydride (NaBH4) as reducing agent. The effects of NaBH4 concentration on the particle size and morphology of the Au and Ag nanoparticles have also been studied. © 2015 Elsevier B.V.

Susanta Sinha Roy

Physics

(SoNS) School of Natural Sciences

Upadhyay R.K.

Soin N.

Saha S.

Barman A.

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Shiv Nadar University

Materials Chemistry and Physics

A versatile green gelator suitable for multiple applications is reported. Gelation of organic solvents in a significantly low gelation time (<5 s) is achieved. The effect of cooling and sonication on gelation time is investigated. Apart from organic solvents, the gelator is capable of forming gels with fuel oils such as diesel and petrol also; therefore, it has been utilized for the separation of oil from an oil/water mixture through selective gelation of the oil. The gelator was also found to be capable of forming hydrogels through rational control of the reaction conditions. Hydrogel prepared using the gelator was further explored as reaction medium for the growth of gold nanoparticles. In the case of nanoparticle synthesis, the gelator served not only as a capping agent but also as a reducing agent. By taking advantage of the dual functionality of the gelator (capping and reducing agent), nanoparticles of both gold and silver were prepared in fluid medium also. The organogel, prepared using toluene and gelator, was utilized for the removal of the waterborne synthetic dye rhodamine B. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Fulltext

New Journal of Chemistry

A versatile carbohydrate based gelator for oil water separation, nanoparticle synthesis and dye removal

Gel is an intermediate phase of solid and liquid, which exhibits properties of both, and this unique feature of gel has made it an excellent choice as a reaction medium for the nanomaterials synthesis. Herein, we report use of oil swollen surfactant gels as reaction medium and exfoliation medium, for the synthesis of metals (Au, Ag) nanoparticles and graphene, respectively. Confined growth of metals (Au and Ag) nanoparticles, has been achieved by exploring tween 80 based surfactant gel as a reaction medium. Au NPs prepared within tween 80 gel were found to be spherical with size ~5 nm, arranged in template micelles. Heating triggered the growth of Au nanoparticles and particles of various shapes including triangles, rods and pentagonal, were produced. Au and Ag containing tween 80 gels were found to be promising as catalysts for the nitrophenol reduction. Apart from separate synthesis of Au and Ag nanoparticles, bimetallic (Au-Ag) nanoparticles have also been synthesized by taking advantage of selective reducing property of tween 80. First time CTAB gel has been utilized as an exfoliation medium for the quick exfoliation of graphite into graphene sheets, eliminating the necessity of any external driving force such as sonication or heating, to reinforce exfoliation. © 2016 Elsevier Inc.

Journal of Colloid and Interface Science

Application of oil-swollen surfactant gels as a growth medium for metal nanoparticle synthesis, and as an exfoliation medium for preparation of graphene

Gold nanoparticles (Au NPs) were synthesized using Au containing CTAB gel as a precursor. The effect of concentration of NaBH4 on the structural, optical, catalytic and electrochemical properties of the Au NPs was also investigated. With the increase of NaBH4 concentration from 0.1 to 0.15 M, an increase in the particle size and change in the morphology from spherical to elliptical was observed. Absorption and emission properties of the Au NPs were also probed using UV–Vis and photoluminescence spectroscopy respectively. Synthesized Au NPs samples were explored as catalyst for the reduction of 4-nitrophenol to 4-aminophenol. Catalytic activity of Au NPs samples prepared using 0.1 and 0.15 M concentration of NaBH4 were also compared. It was found that Au NPs prepared using lower concentration of NaBH4 (Au-0.1) exhibits better catalytic activity compared to the other Au NPs sample (Au-0.15). Synthesized Au NPs were also utilized as electrode material for the detection of Pb2+ ions, results show that Au NPs modified glassy carbon electrode can detect very low concentration of Pb2+ ions (2 µM). Au-0.1 sample exhibited better electrochemical performance compared to the Au-0.15 sample. © 2015, Springer Science+Business Media New York.

Journal of Materials Science: Materials in Electronics

Optical, structural, catalytic and electrochemical properties of the Au nanoparticles synthesized using CTAB based gels

Materials Letters

A novel approach for the synthesis of polyaniline nanostructures using swollen liquid crystal templates

The Analyst

Unusual seedless approach to gold nanoparticle synthesis: application to selective rapid naked eye detection of mercury(ii)

A new reverse worm-like micellar system from a lecithin, multivalent carboxylic acid and oil mixture

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Preparation of gold nanoparticles by surfactant-promoted reductive reaction without extra reducing agent

Physical Chemistry Chemical Physics

Amphiphile nanoarchitectonics: from basic physical chemistry to advanced applications

Fast and facile preparation of CTAB based gels and their applications in Au and Ag nanoparticles synthesis