[Nano-emulsification using ultrasonification]

by

Acknowledgement

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

Signed __________________ Date _________________

Abstract

The underlying purpose of this project is to study the size of the final droplet size using ultrasound technology. A mixture of oil and surfactant water was made to be experimented on where for each section of the experimental procedure one key component (Amplitude, Oil type and Surfactant concentration) was altered keeping the remaining two components constant, in order to be able to evaluate the effects of the modification. The overall experimental time is 120 seconds with readings of droplet size taken at 4, 60 and 120 second intervals. Oils used are Hexane, Dodecane, Octane and Hexadecane. The surfactant used is Sodium Dedocyle Sulphate (SDS) and the concentrations ranged from 0.05g/l to 10g/l (0.05, 0.5, 2, 5 and 10g/l). A nanosizer is used in order to accurately measure the drop size. Results showed, with the increase of phase ratio, final droplet size also increased.

Nomenclature

Amp, Amplitude

C6, Hexane

C8, Octane

C12, Dodecane

C16, Hexadecane

g/l, grams per litre

ml, millilitre

nm, nanometer

o/w, oil in water

SDS, Sodium Dedoclye Sulphate

µm, macrometer

Table of Contents

NOMENCLATURE5

Emulsion7

Emulsions throughout history8

Emulsions are created by surfactants8

Characteristics of emulsions9

Uses of emulsions10

Nanoemulsion15

Methods19

Ultrasound20

Phase inversion24

Drop formation29

Dolphin Picture31

After Breakup32

Drop Coalescence33

Surfactant39

Production And Uses43

THEORETICAL CALCULATION44

EXPERIMENTAL WORK48

Materials48

Apparatus48

Measurement48

Safety considerations48

Method49

RESULTS AND DISCUSSION50

Effects of oil type50

Viscosity51

The Velocity Gradient51

The Coefficient of Viscosity52

Density52

Extremes55

Boiling Point56

Melting point58

Effect of surfactant concentration60

Effects of amplitude at different SDS concentration63

CONCLUSION67

REFERENCES68

Introduction

Emulsion

The majority of oils are less dense when placed in water, and when mixed, remains afloat at the surface. In order to ensure the separation of the two liquids does not occur, industrialists and academics have conjured up a solution whereby mixtures of the two liquids are made, called an emulsion. An emulsion is defined by “a system comprised of two immiscible liquid, one of which is dispersed as droplets (the dispersed or internal phase) throughout the other (the continuous or external phase)” (Agarwal, 2007, 329).

A fluid emulsion creates unique properties which are welcomed within the chemical, food and petroleum industries. The size of the emulsion droplet size determines the measurement standard, Micro (10-100nm), Nano (100-1000nm) and Macro (0.5-100µm) The properties (Stability, Appearance, Rheology, Color, shelf-life and texture) is reliant upon the droplet size and size distributions of the emulsion . An emulsion is the competing process, disruption and coalescence of the dispersed phase (Bainbridge, 2006, 77). To be able to rupture droplets, the laplace pressure must be overpowered, providing sufficient energy is asserted:

?p =

Where ?? is interfacial tension and R is radius of the droplet.

An emulsion is a two-phase system that has at least one immiscible liquid (one incapable of being and remaining mixed), called the dispersed phase, distributed in another liquid or ...