May 05, ; Accepted: June 16, ; Published:
Fortunately, there is a system that can Thesis on biosurfactants you get started. Cosmetic Emulsions Emulsions are one of the most common forms of cosmetic products. You find them in skin lotions, make-up, and even hair products. By definition an emulsion is a dispersion of two or more immiscible materials, where one phase, also know as the internal phase, is dispersed in the continuous or external phase.
Oil in water emulsions are the most common due to preferable cost and light skin feel. In order to create an oil in water emulsion one that remains stable for a long enough timework must be done to overcome the interfacial tension between the two phases.
This can be achieved by mixing; however mixing even at very high rates is not enough to provide long term stability.
An emulsifier or combination of emulsifiers is needed to stabilize droplets of the dispersed phase. For example, simple oil in vinegar salad dressings will separate rapidly without the use of an emulsifier like mustard. Using Surfactants In this industry, we use surfactants to create emulsions. Surfactants are molecules that have a hydrophobic oil soluble and an effective hydrophilic water soluble portion.
They act as emulsifiers by significantly lowering the interfacial tension and decreasing the coalescence of dispersed droplets. HLB Formulating Figuring out what surfactant to use for any specific formula will be a challenge you face as a cosmetic chemist.
There is a great deal of research on surfactants and their behavior. But studying the thermodynamic equations and phase diagrams associated with surfactants can be a daunting task, not to mention the number of surfactants available to the formulator is vast.
Luckily for us, William C. Griffin developed a way to streamline the selection of surfactants by utilizing the ratio of the hydrophobic to the hydrophilic portion of the molecule. Griffin first presented this method at meeting of the Chicago Chapter of the Society of Cosmetic Chemists in and it is still widely used today.
He published the method shortly there after. And using the HLB system to create emulsions is quite simple.
Determining the HLB of a surfactant A typical nonionic emulsifier e. Laureth-4 contains an ethylene oxide groups or polyhydric alcohol hydrophilic portions with a fatty alcohol hydrophobic portion. The HLB for a nonionic surfactant can be calculated as follows: Division by 5 just allows for a compact, easy to use scale.
These required HLB values are determined experimentally, however a method utilizing solubility parameters has been proposed by Vaughan and Rice. It is also important to keep in mind that cosmetic emulsions often have complex oil phases with several components.
The required HLB of an oil phase mixture can be calculated by first calculating the percent of the oil phase each ingredient contributes. This percentage is then multiplied by the required HLB for each of those ingredients and the results are summed.
Shea butter contribution 0. A blend of high and low HLB surfactants is often used to achieve the desired value in part because of demonstrated effectiveness and efficiencies in packing at the interface. For example additional water phase ingredients are not considered but still may impact the stability.1.
Introduction. Genus Pseudomonas produces a variety of extra-cellular pigments of which phenazines comprise the most significant one. The most characteristic feature of Pseudomonas aeruginosa is the production of soluble pyocyanin pigment: a water soluble blue green phenazine compound.
From the beginning, pyocyanin had been used as a reversible dye with a redox potential similar to that of. View Biosurfactants Research Papers on yunusemremert.com for free.
A THESIS ABOUT BIOSURFACTANT. SURFACTANT The word “ surfactant” is a contraction of three word “ Surface Active Agent”. So surfactants are materials that lower the surface tension or interfacial. Because of this, it is among the most significant efforts well visit is often one of his career thesis biosurfactant production + included teaching, performing and recording of a healthy potential in gen - dered beings, need to do with and warranted within the classroom.
INTRODUCTION. Biosurfactants can be defined as the surface-active biomolecules produced by microorganisms with wide-range of applications. In recent years, due to their unique properties like specificity, low toxicity and relative ease of preparation, these .
Ron, ) suggested, biosurfactants could be divided into low molecular mass molecules that efficiently lower surface and interfacial tension, and large molecular- mass polymers, that are more efficient as emulsion-stabilizing agents.