scholarly journals Stability and Aggregation Kinetics of Silver Nanoparticles in Water in Oil Microemulsions of Cetyltrimethylammonium Bromide and Triton X-100

2017 ◽  
Vol 9 (4) ◽  
pp. 431-447 ◽  
Author(s):  
F. Begum ◽  
S. A. Jahan ◽  
M. Y. A. Mollah ◽  
M. M. Rahman ◽  
M. A. B. H. Susan
Keyword(s):  
Silver Nanoparticles ◽  
Cetyltrimethylammonium Bromide ◽  
Molar Ratio ◽  
Aggregation Kinetics ◽  
Average Particle ◽  
Time Intervals ◽  
Size Stability ◽  
Triton X ◽  
Kinetics Of ◽  
Preparative Route

Water in oil (W/O) microemulsions are simple preparative route for nanoparticles where water droplets dispersed in oil stabilized by surfactant or surfactant and cosurfactant monolayer act as nanoreactors to carry out chemical reactions. In this work, silver nanoparticles (AgNPs) were prepared in W/O microemulsions of cetyltrimethylammonium bromide (CTAB) and triton X-100 (TX-100) by using AgNO3 and NaBH4 as a precursor salt and reducing agent, respectively. To prepare microemulsions, CTAB or TX-100, 1-pentanol, cyclohexane and water were mixed with different molar ratio. AgNPs were prepared with different [AgNO3] in microemulsions of CTAB with fixed water to surfactant ratio (Wo). Average particle sizes were determined from dynamic light scattering (DLS) measurements. AgNPs prepared from microemulsions of CTAB were unstable while from TX-100, NPs were stable. Aggregation kinetics was investigated by measuring the absorbance at definite time intervals at the absorption maximum, ?max of AgNPs in different media under pseudo-first-order conditions. The aggregation behavior was studied at different [AgNO3]:[NaBH4] and Wo and the parameters were optimized to ensure formation of stable AgNPs without aggregation in microemulsions. This would help tuning the size, stability, and aggregation kinetics of AgNPs by controlling the nature of the surfactant and composition of the microemulsions.

The impact of stabilization mechanism on the aggregation kinetics of silver nanoparticles

2012 ◽  
Vol 429 ◽  
pp. 325-331 ◽  
Author(s):  
Amro M. El Badawy ◽  
Kirk G. Scheckel ◽  
Makram Suidan ◽  
Thabet Tolaymat
Keyword(s):  
Silver Nanoparticles ◽  
Aggregation Kinetics ◽  
Stabilization Mechanism ◽  
The Impact ◽  
Kinetics Of

Influence of dissolved oxygen on aggregation kinetics of citrate-coated silver nanoparticles

2011 ◽  
Vol 159 (12) ◽  
pp. 3757-3762 ◽  
Author(s):  
Wen Zhang ◽  
Ying Yao ◽  
Kungang Li ◽  
Ying Huang ◽  
Yongsheng Chen
Keyword(s):  
Silver Nanoparticles ◽  
Dissolved Oxygen ◽  
Aggregation Kinetics ◽  
Kinetics Of

Preparation of Nano-TiO2 Using a Sol-Gel Process Mediated in Reverse Microemulsion Combined with a Solvent Thermal Technique

2011 ◽  
Vol 287-290 ◽  
pp. 1731-1734 ◽  
Author(s):  
Han Sheng Li ◽  
Hang Xu ◽  
Shi Ying Wang ◽  
Ya Lin Pan ◽  
Qin Wu ◽  
...  
Keyword(s):  
Sol Gel ◽  
Average Particle Size ◽  
High Photocatalytic Activity ◽  
Reverse Microemulsion ◽  
Molar Ratio ◽  
Average Particle ◽  
Anatase Structure ◽  
Sol Gel Process ◽  
Triton X ◽  
Thermal Technique

Anatase nano-titania (nano-TiO2) was prepared by using a sol-gel process mediated in reverse microemulsion combined with a solvent thermal technique. The results show that the anatase structure appears in the calcination temperature range of 400-510°C, while the transformation of anatase into rutile takes place above 510°C. The average particle size (dP) of the nano-TiO2 increases with the rise of water/Triton X-100 molar ratio (ω) but decreases with the rise of acetyl acetone/n-TBT molar ratio (p) and n-hexanol/Triton X-100 molar ratio (m). The obtained TiO2 particles with a small size have high photocatalytic activity.

scholarly journals Kinetics of Vibrio cholerae sialidase action on gangliosidic substrates at different supramolecular-organizational levels

1982 ◽  
Vol 203 (3) ◽  
pp. 735-742 ◽  
Author(s):  
Bruno Venerando ◽  
Benvenuto Cestaro ◽  
Amelia Fiorilli ◽  
Riccardo Ghidoni ◽  
Augusto Preti ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Vibrio Cholerae ◽  
Bovine Serum ◽  
Mixed Micelles ◽  
Molar Ratio ◽  
Free Carbohydrates ◽  
Triton X ◽  
Kinetics Of ◽  
Vibrio Cholerae Sialidase

Gd1a, Gd1b and Gt1b gangliosides were dispersed in the following membrane-mimicking systems: (a) homogeneous micelles; (b) mixed micelles with Gm1 ganglioside (which is resistant to the enzyme action), Triton X-100 or bovine serum albumin; (c) small unilamellar vesicles of egg phosphatidylcholine. The effect of dispersion on sialic acid release by Vibrio cholerae sialidase was studied. As reference substrates freely interacting with the enzyme the lipid-free carbohydrates of Gd1a and 3′-sialosyl-lactose were employed. The apparent Vmax. of the enzyme was, with all the gangliosides, dependent on the type of ganglioside dispersion. It was lowest for homogeneous micelles and mixed micelles with ganglioside Gm1, and increased about 6-fold for ganglioside/bovine serum albumin lipoprotein micelles, 15-fold for mixed-ganglioside/Triton X-100 micelles (optimal molar ratio 1:7.5) and 30-fold for phosphatidylcholine vesicles containing 2.5 mol% ganglioside (this proportion was optimal for enzyme activity on the vesicles). For ganglioside Gd1a, the activity on Triton X-100 mixed micelles and on mixed vesicles was even greater (3- and 6-fold respectively) than that displayed on Gd1a lipid-free carbohydrate. With each of the used gangliosides the apparent Km values were very similar values for homogeneous micelles and vesicular dispersions, but showed marked increases for Triton X-100 mixed micelles, approaching the values exhibited by reference oligosaccharides. Triton X-100 micelles and phosphatidylcholine vesicles did not appreciably alter the kinetics of sialidase action on 3′-sialosyl-lactose and on Gd1a lipid-free carbohydrate, indicating that the above effects are dependent on the intrinsic characteristics of the membrane-like systems containing gangliosides.

Kinetics of Silver Nanoparticle Growth Using DMF as Reductant – Effect of Surfactants

2014 ◽  
Vol 938 ◽  
pp. 30-35 ◽  
Author(s):  
Paramita Sarkar ◽  
Chithra Parameswaran ◽  
C. Harish ◽  
M. Bhanu Chandra ◽  
A. Nirmala Grace
Keyword(s):  
Silver Nanoparticles ◽  
Dimethyl Formamide ◽  
Ammonium Bromide ◽  
Time Intervals ◽  
Nanoparticle Growth ◽  
Formation Kinetics ◽  
Regular Time ◽  
Vis Spectroscopy ◽  
Cetyl Trimethyl Ammonium ◽  
Kinetics Of

Silver nanoparticles are synthesized using N,N dimethyl formamide (DMF) both as reductant as well as solvent. The reaction is performed in the presence and absence of surfactants at room temperature to know the effect of the same on the size and shape of the silver nanoparticles. In this regard, two different surfactants viz. polyvinylpyrolidone (PVP) and cetyl trimethyl ammonium bromide (CTAB) are used. The rate of the reaction and the formation kinetics is continuously monitored by UV-vis spectroscopy at regular time intervals. The corresponding change in plasmonic peaks and full width half maxima (FWHM) is studied in detail. The particle size is determined using Mie plot.

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