Stable and Oriented Liquid Crystal Droplets Stabilized by Imidazolium Ionic Liquids

Liquid crystals represent a fascinating intermediate state of matter, with dynamic yet organized molecular features and untapped opportunities in sensing. Several works report the use of liquid crystal droplets formed by microfluidics and stabilized by surfactants such as sodium dodecyl sulfate (SDS). In this work, we explore, for the first time, the potential of surface-active ionic liquids of the imidazolium family as surfactants to generate in high yield, stable and oriented liquid crystal droplets. Our results show that [C12MIM][Cl], in particular, yields stable, uniform and monodisperse droplets (diameter 74 ± 6 µm; PDI = 8%) with the liquid crystal in a radial configuration, even when compared with the standard SDS surfactant. These findings reveal an additional application for ionic liquids in the field of soft matter.

The effect of surfactant concentration on nanoparticles surface wettability during wettability alteration of oil-wet carbonate rock

Previous studies reported that the presence of surfactant increases nanoparticles surface wettability by in-situ surface activation. On the other hand, the excess of surfactant concentration has an inverse effect on particle hydrophobicity by altering it to be hydrophilic back. Hence, this study presents an experimental investigation of wettability alteration by using a surfactant-nanoparticles system by using cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactant, and hydrophilic silicon dioxide (SiO2) and partially hydrophobic silicon dioxide (PH SiO2) nanoparticles. The nanoparticles surface wettability and the wettability alteration of oil-wet carbonate rock were measured by using the contact angle method. The result shows that the contact angle of the oil-wet carbonate rock was most reduced by using CTAB-hydrophilic SiO2, from 112.00o to 28.35o. The excess of surfactant concentration (beyond CMC) shows an inverse effect on particle surface wettability, however, induces the water-wetness of the carbonate rock. Besides, the hydrophilic SiO2 shows a more effective effect as a wettability modifier than the PH SiO2, in the absence and presence of CTAB or SDS surfactant.

Reversible Assembly of Silica Nanoparticles at Water-Hydrocarbons Interfaces Controlled by SDS Surfactant

Achieving reversible and tunable assembly of silica nanoparticles at liquid-liquid interfaces is vital for a wide range of scientific and technological applications including sustainable subsurface energy applications, catalysis, drug delivery...

Tuning of Silica Nanoparticles-Lysozyme Protein Complexes in presence of SDS Surfactant

The structure of complexes of anionic silica nanoparticles (size16 nm)-lysozyme (cationic) protein, tuned by the addition of anionic surfactant sodium dodecyl sulfate (SDS), has been investigated by dynamic light scattering...

Alteration wettability of carbonate rocks by Nano fluids and comparison with PEG and SDS

This work was conducted to study limestone rock wettability alteration to enhance oil recovery by flooding using different Nano silica (NS) sizes suspended in saline water and compared with flooding solution of polyethylene glycol (PEG) polymer and sodium dodecyl sulfate (SDS) surfactant, the stability of nanofluids measured by zeta potential. In the flooding system, the secondary recovery by silica nanofluids (0.01 wt. % NS concentration) achieved an oil recovery of 35vol. % and 26.08 vol. % for 10, 52 nm after primary recovery respectively, while PEG polymer and SDS surfactant achieved oil recovery of 5 vol. % and 10 vol. % only respectively. The stability of pressure difference approved that silica nanoparticle never causes any plug or damage for the carbonate rocks

Production and Optimization of Biosurfactants from Citrullus lanatus Seeds and Activity Determination with Pseudomonas aeruginosa Isolate

Aims: To produce and optimize biosurfactants from Citrullus lanatus seeds. Study Design: Randomized design. Place and Duration of Study: Department of Biochemistry Lab. and Department of Microbiology lab. University of Nigeria, Nsukka, between April and August, 2017. Methodology: Biosurfactants were produced in two fermentation media consisting of basal mineral medium+ watermelon (C. lanatus) seed (BMM+WMS), and Nutrient broth (NB). Optimization of production process was carried out with respect to time/duration of fermentation and pH of production which indicated 7 days fermentation period at pH 8.0. The Pseudomonas aeruginosa used was isolated from soil. The biosurfactants stability under some environmental conditions were studied using; Thermostability test at 30°C, 60°C, and 100°C; Halostability test with %w/v concentration of NaCl in; 2%NaCl, 5%NaCl, 7%NaCl, and 10%NaCl; pH stability test was conducted with pH 2.0, pH 4.0, pH 6.0, pH 8.0, pH 10.0, and pH 12.0. Results: Proximate analysis(%) showed; protein (0.317­ ± 0.02), lipid (17.66 ± 0.17), carbohydrate (62.77 ± 0.21), ash (2.33 ± 0.24), fibre (4.84 ± 0.79), and moisture (12.06 ± 0.17).The Emulsification index (E24) for the crude biosurfactant solutions (supernatants) that resulted from the two production media, and sodium dodecyl sulfate 1% SDS in distilled water (control) using palm oil (PO), olive oil (OO), engine oil (EO), kerosene (KR), and petrol (PT) for BMM+WMS biosurfactant gave PO (79.66±1.52%), OO (64.66±7.23%), EO (15.33±4.93%), KR (12.66±6.50%), and PT (0.00±0.00%). Also, the NB biosurfactant resulted in; PO (71.00±2.00), OO (54.33±3.78), EO (42.66±6.42), KR (22.66±7.57), and PT (0.00 ± 0.00) E24 values. There were significant decreases (p<0.05) in biosurfactants activities in all vegetable oils and hydrocarbons when compared to the SDS surfactant. However, there was no significant decrease (p>0.05) in WMS biosurfactant activity in palm oil compared to SDS surfactant activity in palm oil. Conclusion: The biosurfactants were shown to have high thermostablity as their E24 values increased with rise in temperature.