Aqueous foams stabilized with silica nanoparticle and alpha olefin sulfonates surfactant

Carbon dioxide (CO2) foams have been introduced to improve mobility of CO2 in CO2 flooding. However, using surfactant alone to stabilize CO2 foam has potential weaknesses such as high surfactant retention in porous media and the foam is thermodynamically unstable for a long-term. Nanoparticle has been an alternative in stabilizing CO2 foam longer. This study aims to analyze CO2 foam stability at varying concentrations of surfactant, silica nanoparticle (SNP) and brine. The additions of SNP in anionic surfactant of alpha olefin sulfonates (AOS)-water and in AOS-brine towards foam stability were demonstrated in this study. CO2 foam stability was measured through the foam height observation and bubble size analysis. The performance of SNP and AOS suspensions in stabilizing foam were observed at different concentrations of AOS (0.1, 0.3 and 0.5 wt%), SNP (0.1, 0.3 and 0.5 wt%) and brine (0.1, 1 and 5 wt%). The results revealed that the CO2 foams were most stable at 0.3 wt% SNP suspension in 0.5 wt% AOS-water. It was found that the most stable foams formed at concentration of 1 wt% of brine. Smaller and uniform bubble size has been produced at 0.3 wt% SNP in 0.5 wt% AOS solution. Thus, concentrations of surfactant, SNP and brine have significant effects on CO2 foam stability

Electrophoretic mobility of Tween 80-encapsulated agarwood oil in aqueous

A study on the feasibility of using gel electrophoresis technique in grading the agarwood oil quality was investigated. Prior to electrophoresis, the emulsified agarwood oil droplets were screened by a diffuse layer of ions that have equal absolute charge to that of the droplets surface charge in aqueous phase. The condition was obtained by varying the concentrations of non-ionic surfactant; Tween 80 until the critical aggregation concentration (CAC) value of 0.0167% (v/v) was achieved. The prepared droplets suspended in the aqueous within nano-metre size and had ability to migrate through the agarose gel with its own specific electrophoretic mobility. However, due to the limitation of gel pore size, only large oil droplets (>200 nm) indicated visible bands. Overall, a novel work for grading the emulsified agarwood oil droplet with its own electrical properties was feasible

Nanoparticle preparation of mefenamic acid by electrospray drying

Nanoparticles preparation of Mefenamic acid (MA) by using an electrospray drying method was conducted in this study. Electrospray drying is a process that uses electrostatic force to disperse a conductive liquid stream into fine charged droplets through the coulomb fission of charges in the liquid and finally dry into fine particles. Electrospray drying modes operation usually in Taylor cone jet, and it was formed by controlling applied voltage and liquid flow rate. A conductive liquid (2.77–8.55μScm−1) which is MA solution was prepared by using acetone with concentration 0.041 and 0.055 M before pumping at a flow rate of 3–6ml/h. By applying the applied voltage at 1.3–1.5 kV, Taylor cone jet mode was formed prior to the electrospray. During electrospray drying process, solvent evaporation from the droplet was occurring that leads to coulomb disruption and may generate to nanoparticles. The dried nanoparticles were collected on a grounded substrate that was placed at varying distance from the electrospray. MA particle with size range of 100–400 nm were produced by electrospray drying process. Characterization of particles by using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) show that particles formed into polymorph I

Uniformity investigation of deposited nanoparticles via pulse direct current (DC) in electrophoretic deposition (EPD) / Rabiatul Adawiyah Abdol Aziz, Noor Fitrah Abu Bakar and Mohd Nazli Naim

Nowadays, with increasing thrust on nanostructured materials, Electrophoretic Deposition (EPD) technique is being viewed with more interest for assembly of nanoparticles. It covers a wide range of applications such as photonic materials, high density magnetic data storage devices, microchip reactors and biosensors. Obviously, the use of water/aqueous implies advantages such as a faster kinetics, in addition to important health, environmental, and cost benefits. However, it causes a number of problems in electrophoretic forming mainly related to electrochemical reaction in the electrodes when current is passed through, which seriously affects the efficiency of the process and the uniformity of the deposit. Different sizes of standard nanoparticles i.e. polystyrene latex (PSL) particles will be diluted with milipore water into several concentration media and it will be sonicated . pH of the aqueous will be prepared in acid and alkaline media by adding HCl and NaOH respectively. Carbon and copper electrode will be submerged in the media. EPD with Direct Current (DC) voltage will be applied during the deposition process. The deposited particle will be weighed with balancer. For the case of pulse DC, different frequency of pulse cycle will be applied. The deposited particles will be analyzed using X-ray Diffraction (XRD). The morphology of the deposited naoparticles will be analyzed by using Scanning Electron Microscopy (SEM). Distribution of the deposited particle will be characterized iether by using EDS analyzer in SEM. In this work, we propose to evaluate the uniformity of the deposited particles with EPD technique, pulse DC will be applied in the experiment with different frequency of pulse cycle

Transformation of cyclodextrin glucanotransferase (CGTase) from aqueous suspension to fine solid particles via electrospraying

In this study, the potential of electrohydrodynamic atomization or electrospraying to produce nanometer-order CGTase particles from aqueous suspension was demonstrated. CGTase enzyme was prepared in acetate buffer solution (1% v/v), followed by electrospraying in stable Taylor cone-jet mode. The deposits were collected on aluminium foil (collector) at variable distances from the tip of spraying needle, ranging from 10 to 25 cm. The Coulomb fission that occurs during electrospraying process successfully transformed the enzyme to the solid state without any functional group deterioration. The functional group verification was conducted by FTIR analysis. Comparison between the deposit and the as-received enzyme in dry state indicates almost identical spectra. By increasing the distance of the collector from the needle tip, the average particle size of the solidified enzyme was reduced from 200 ± 117 nm to 75 ± 34 nm. The average particle sizes produced from the droplet fission were in agreement with the scaling law models. Enzyme activity analysis showed that the enzyme retained its initial activity after the electrospraying process. The enzyme particles collected at the longest distance (25 cm) demonstrated the highest enzyme activity, which indicates that the activity was controlled by the enzyme particle size

Fabrication and characterization of electrospun κ-carrageenan based oral dispersible film with vitamin C

Oral dispersible films (ODF) are great alternatives to tablet medications as they will simply dissolve in the mouth. There are several ways to produce ODFs, but electrospinning is emerging as one of the best methods as it increases the surface to volume ratio which allows it to dissolve easily. ODFs are typically formulated using a combination of polymers to produce the necessary film qualities. The use of κ-carrageenan (κ-CAR), a natural polymer in ODFs are yet to be studied in detail. Therefore, this study aims to develop an ODF from a combination of κ-CAR, polyvinyl alcohol (PVA) and vitamin C, where the latter will act as a model drug carrier. 1.5w/v% κ-CAR and 14w/v% PVA at a ratio of 30:70 was added with different concentrations of vitamin C from 2 to 10w/v%, respectively. The resulting nanofibers were then examined for morphology, water contact angle (WCA) and disintegration time. All the solutions formed uniform nanofibers with an average diameter ranging from 190 to 490 nm and showed hydrophilic properties. Sample 4 showed the fastest disintegration time of 3.68 s and the lowest WCA of 38.5°. The results indicated that the best formulation for an ODF was with 8% vitamin C. The findings from this study provide promising groundwork for the use of κ-CAR as the biopolymer in combination with the PVA to develop a biopolymer-based ODF with vitamin C via electrospinning

Stabilisation of emulsified Agarwood oil in an aqueous system using non-ionic surfactant

Owing to the annually increasing market value of pure agarwood oil, the extractedagarwood oil from Aquilaria malaccensis was emulsified in an aqueous solution using non-ionic surfactant (Tween 80). The surfactant concentration of 0.0167% was determined as the criticalmicelle concentration (CMC) with an interfacial tension value of 0.014 mNm-1. The adsorption of surfactant at the oil/water interface at the CMC value, however, reduced the zeta potential of the emulsified oil from –45 to –43 mV, and increased its size from 85 to 89 nm. Outside of the CMC value, the emulsified oil droplets tended to coalesce, owing to insufficient coverage of the surfactant at oil/water interface and Ostwald ripening. The droplet size distribution and zeta potential value of the emulsified oil droplets produced at the CMC were the most stable over a month of storage. No significant changes in the emulsified droplet size occurred when the pH conditions varied from pH 3 to 10. The emulsified droplets images obtained from transmission electron microscopy analysis showed a reduction in the layer thickness of the surfactant from 30 to 10 nm in acidic condition and 30 to 19 nm in alkaline condition. The agarwood oil emulsification at CMC value enhance the stability of chemically unstable compounds from degradation

Deposition of nanostructures derived from electrostatically stabilised TiO2 aqueous suspension onto a biocomposite

A nanostructure derived from TiO2 particle deposition onto a biocomposite surface derived from coir dust (CD) was developed to control degradation using a spray dry technique. To stabilise and reduce the size of dispersed particles, the TiO2 powder was prepared in deionised water at pH 10 and sonicated at 20kHz and 400W. The coir dust was obtained from coconut kernel waste and underwent drying treatment before it was mixed with polypropylene (PP) as the substrate. The suspension consisted of particles with an average size and zeta value of 285nm and -19.2mV, respectively. The suspension was spray dried onto a hot-pressed substrate (biocomposite) with a surface roughness between 0.23 and 1.57μm at ambient temperature. Scanning electron microscopy image analysis and Fourier transform infrared spectroscopy analysis indicated that the TiO2 particles were successfully deposited onto the substrate, shown by the existence of a carboxylic acid group (COOH) in the CD matrix. Moreover, the weight of the deposited substrate increased exponentially with deposition time compared to pure PP substrate. However, the deposition rate of TiO2 nanoparticles was limited by the ratio of the substrate surface roughness to particle diameter, as predicted by a previous study