Nanoemulsion
Introduction
“Emulsions are dispersions of droplets of a liquid phase in a different immiscible liquid. Oildroplets dispersed in water are known as (direct emulsions), whereas water droplets dispersed inoil are called (inverse emulsions) “
nanoemulsions are thermodynamically stable and isotropically clear dispersions of two liquids which are immiscible . ex (oil in water or vice versa), which are stabilized by surfactant molecules forming an interfacial film. They are known to be kinetically stable dispersions of oil and water phase along addition of a surfactant.
Small particles or droplets are usually present in the dispersed phase of nanoemulsions and they have a size range of five to two hundred nm, and the o/w interfacial tension is low. They are transparent due to the droplet size being lower than twenty five percent of the visible light wavelength. The nanoemulsions are formed spontaneously and readily, usually with low-energy input. Most dispersions require a co-solvent along with the surfactants in oil and water phase.
Nanoemulsions can be subdivided into 3 types of dispersions relying on the composition:
• Oil in water nanoemulsions, droplets of oil are immersed in water phase.
• Water in oil nanoemulsions, droplets of water are immersed in oil phase.
• Bi-continuous nanoemulsions, oil and water micro-domains are interspersed in the system.
There are 3 main components of nanoemulsions such as:
• Oil
• Surfactant
• Co-solvent
They are colloidal immersions composed of oil, aqueous, surfactants and co-surfactant at required ratios. They are different compared to coarse emuslions which are micronized by external force, by the usage of co-surfactants, nanoemulsions are showing low interfacial tension. ...
... middle of paper ...
...aches transparency.
A pseudo-ternary phase diagram is used to determine the percentage of oil phase, the content of surfactant and co-surfactant that should be added. To acquire the wanted size range for the dispersed droplets we use an Ultrasonicator for the dispersion to reach equilibrium. For the formation of a gel we can add a gelling agent ( carbomers) to the nanoemulsion.
Factors taken in consideration when preparing nanoemulsions:
• caution should be taken while choosing a surfactant to achieve a very low interfacial tension in the o/w interface (< 10-3 mN/m).
• a high concentration of surfactant should be attained in order to give enough molecules of surfactants required for the stabilization of the micro-droplets for the production of a very low interfacial tension.
• Flexibility or fluidity is a property which is needed in the formation of nanoemulsions.
Fig. 2(A) shows the phase diagrams of IPM, water, and surfactant mixtures at the ratios of 60:40, 65:35, and 70:30 (v/v), respectively. Fig. 2(B) shows the phase diagrams of ethyl oleate, water, and surfactant mixtures at ratios of 90:10, 95:5 and 100:0, respectively. Filled circles mean self-emulsifying points, and black areas represent the self-emulsifying regions. In other area, the compositions showed inverted emulsion, gel-like form, or phase-separation. In general, when the oil content in the oil and surfactant mixtures is ≤30%, the condition of the mixtures changed from water-in-oil emulsion to a clear gel-like form and then to microemulsion. Otherwise, the dispersions showed phase separation, this result was similar to the results previously studied by Guo et al. [16]. Our finding showed that IPM + surfactant mixture (65:35, v/v) and ethyl oleate + surfactant mixture (90:10, v/v) showed the most self-emulsifying regions (Fig. 2). Overall, in contrast to IPM + surfactant mixture (65:35, v/v), ethyl oleate + surfactant mixture (90:10, v/v) showed finer emulsion in larger self-emulsifying range. These results indicate that ethyl oleate and Tween 80:Carbitol (90:10, v/v) were identified as the optimal oil
Amandi Hiyare: Before forming my research question, I had a discussion with my research project coordinator “Lisa Pope” who told me that the Flinders nanotechnology research team has been developing microbial catheters. Then on Monday I had an interview with Professor Joe Shapter who told me that your team was leading this project. So I was wondering whether you would be able to provide me with some detailed information about this innovation?
Molecules attract one another’s opposite partial pole due to London dispersion and Coulomb force. Substances in a mixture are not chemically bonded. There are four types of intermolecular bonds with ethanol which are London dispersion, dipole-dipole, covalent, and hydrogen. Ethanol will interact with water and bond producing a tightly bonded mixture, where as vegetable oil does not mix with water molecules. Theses structures are depicted in the figure below:
is reached between the surfactant monomers at the interface and those in the bulk, surfactants
Working: when water ingression occurs in stern tube some kind of bio-lubricants can absorb any sea or fresh water entering the tube and form a stable emulsion thereby reduci...
Nanotechnology is defined as the science of design, synthesis and characterization of matter at the nanoscale, which mesures one billionth of the meter [1,2] On that scale, structures exhibit novel chemical, physical and biological properties and processes, which enables the creation of engineered nanomaterials (ENMs), with various characteristics and potential applications. [3] It’s not just that though. Nanotechnology shows the ability to eliminate the gaps among medicine, material engineering and science, computer technology and public policy, creating new clinical and medical approaches to better diagnose, treat and prevent any kind of illness. In fact, it is already moving from simple passive structures
An emulsion is a mixture of two immiscible liquids. Immiscible liquids, such as water and oil, are unable to mix without a third party, which in this experiment is the xanthan gum and whey powder, because of the polarity of the liquids. Because water is polar and oil is not, it is impossible for both of them to be mixed.
They are usually made up of surfactants, which are surface active agents which reduce the surface tension of water by absorbing the common boundary between more than one liquid (3). The amphipathic character of detergents is evident in their structures, which consist of a polar (or charged) head group and a hydrophobic tail. Depending on the head of the detergent they can either be ionic, nonionic, and zwitterionic. This is dependent on the stereochemistry of the entire detergent. Detergent monomers self-associate to form structures called micelles. When the concentration exceeds the CMC, a detergent becomes capable of solubilizing hydrophobic and amphipathic molecules, such as lipids, into mixed micelles or micellar aggregates( ). In micelles, the amphiphilic lipid has a tail that forms a core that encapsulates an oil droplet or dirt particle and a head that maintains contact with the surrounding water environment. To work effectively, the chemical formation of micelles is not enough to remove oil or grease; mechanical energy (scrubbing or water flow) is often required
Therefore, oil and water do not mix. This is why Oil does not dissolve when you run water over it. How does the oil wash off your hands if the water isn¡¦t soluble with the oil? This is where soap comes in. While soaps head is attracted to water its tail is attracted to non-polar substances such as oil. When oil and grease etc. mix with oil it creates a slightly polar substance because of the head group. This makes the oil soluble with water allowing you to wash off your hands with water and rinse the grease off.
In the novel, Prey, written by Michael Crichton it pertains to the subject of nanotechnology throughout the whole entire book. The main characters of this novel are the
Oil dispersant is a chemical mixture of surfactants and solvents that helps break up oil into small droplets following an oil spill. Similarly to the way soaps or detergent work, dispersants break up large oil slicks lying on the top of water into smaller manageable particles (Pam, 2010). Dispersants are primarily composed of solvent and surfactants. The role of solvents is to reduce the viscosity of surfactants in order to be easily sprayed. In addition, solvents promote the penetration of the surfactants into the oil slick. On the hand, surfactants are surface active agents that are used to reduce surface tension between water and oil so as to increase wettability. The effectiveness of oil dispersants depends on the hydrophilic-lipophilic balance (HLB) –which is a coding scale from 0, to 20. A zero value corresponds to the most lipophilic and a value of 20 is the most hydrophilic. Oil dispersants usually have HLB values from 8–18 (G.P.Lindblom,
This is an example of a soap molecule. The hydrocarbon end is non polar and hydrophilic (water hating) and the carboxylate end is polar and hydrophilic (water loving). This the property which allows it to clean, it acts as an emulsifying agent. The soap disperses in water to form miscelles where a negatively charged surface is formed and hydrocarbon chains are in the centre. These miscelles surround droplets of dirt or grease suspending them in the water so they can be washed away.
Thickening agents or binders to keep the toothpaste together. They include mineral colloids, natural gums, seaweed colloids or synthetic cellulose.
The usual method of cleaning an oil spill would have been to use a dispersant powder to chemically clear the water. However, because of how thick the layer of oil was, the powder barely made a dent. Unfortunately, it took days for the clean-up crew to realize the ineffectiveness of the dispersant,
I have chosen nanotechnology as my topic area of choice from the food innovation module.