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

Abstract

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 AgNO 3 and NaBH 4 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 [AgNO 3 ] in microemulsions of CTAB with fixed water to surfactant ratio (W o ). 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, λ max of AgNPs in different media under pseudo-first-order conditions. The aggregation behavior was studied at different [AgNO 3 ]: [NaBH 4 ] and W o 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.

A green approach to nanoplastic detection: SERS with untreated filter paper for polystyrene nanoplastics

“…In agreement with previous studies, [75][76][77] the non-ionic surfactant (Triton X-100) and cationic surfactant (dodecyl trimethyl ammonium bromide, DTAB) showed the highest ability to stabilize and prevent the aggregation of AgNPs, compared to an anionic surfactant (sodium lauryl sulfate, SLS). These long-chain surfactant polymers are generally coated on the surface of AgNPs against aggregation and, thus, Paper Analyst affect the contact of the analyte with the AgNPs, resulting in a reduced or restricted SERS sensitivity.…”

Dissolution of silver nanoparticles in colloidal consumer products: effects of particle size and capping agent

“…Matrix components, like oils, may interfere with DLS measurements (Instruments 2007). Despite this limitation, we believe the increasing or decreasing diameter trend over time is still accurate (Begum et al 2017). HDD populations are identified using the DLS plot of volume (percent) vs. particle diameter (nm).…”

“…The reason for this difference is that DLS is susceptible to change in capping agent and matrix (Cascio et al 2014). Oilcontaining matrices may interfere with the accuracy of DLS measurements but the change in HDD over time can still indicate a trend (Begum et al 2017).…”

Production of sub-micro sized silver particles by chemical reduction method in an environmentally-friendly manner

“…Their properties are related to very high surface to volume ratio and quantum size effects. For nanoparticle synthesis, the most used pure metals are copper, silver, and precious metals (gold, platinum, and palladium) [6][7][8], with silver being the dominant one [9], due to their general properties, as well as chemical stability, ease of obtaining, and favorably priced compared with others [10]. For some purposes, the benefit of the unique properties of AgNPs has been exploited for nanocomposite powders production based on mixed metals or their oxides [11].…”