Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.787483
Title: Investigation into the physical and chemical properties of soap bubbles with respect to their performance
Author: Zelmer, Anna
ISNI:       0000 0004 7972 596X
Awarding Body: Bangor University
Current Institution: Bangor University
Date of Award: 2019
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Abstract:
This thesis describes an investigation into components of a formulation intended to make (giant) soap bubbles. Chapter 1 reviews background information on soap films and foams, while chapter 2 includes a systematic study into the effects of three different types of surfactants on properties linked to soap bubble stability, namely life time of 1 cm diameter single bubble, foamability, foam stability and water retention in bulk solution. Finally, chapter 3 is concerned with the practical application of making giant soap bubbles and improving formulations for this application. Surfactants are the crucial component when making soap bubbles and sodium alkyl sulfates, alkyl trimethylammonium bromides and alkyl maltosides of different alkyl chain lengths, representing anionic, cationic and non-ionic surfactant types, respectively, were chosen to determine structural effects of surfactants that increase bubble stability. It was found that the ionic surfactants gave better foamability and single bubble life times. However, foam stability and water retention in bulk solution were much better for the non-ionic surfactants. In mixtures between the ionic and non-ionic surfactant, single bubble life time and foamability are dominated by the ionic surfactant concentration, whereas foam stability and water retention are dependent on the alkyl maltoside concentration. This can be explained by the ability of maltoside surfactants to form intermolecular hydrogen bonds whereas both foam ability and single bubble lifetime are dependent on the higher surface activity of the ionic surfactants due to electrostatic interactions. Furthermore, foam stability and single bubble lifetime was found to be at a maximum at alkyl chain lengths of 14 for ionic and 10 for the non-ionic surfactants. Surfactants with those alkyl chain lengths provided good results in the formulation of solutions for making giant soap bubbles as discussed in chapter 3. Furthermore, mixtures of sodium dodecyl sulfate (S-12-S) and amine oxide type non-ionic surfactants with mixed alkyl chain length were found to give the best surfactant properties. Surfactant activity is highly pH dependent and a pH range of 6.5-7 provided best bubble performance. Another important ingredient in formulations intended to make giant soap bubbles are polymers. And a blend of hydroxyethyl cellulose (HEC) and polyethylene oxide (PEO) was found to enhance performance of giant bubbles. One of the major factors limiting the life time of soap bubbles is water evaporation and to reduce this, humectants were included in the formulation. Furthermore, a preservative suitable for inclusion in this formulation under toy safety standards was required and both sodium benzoate and phenoxyethanol provided satisfactory options. This thesis provides a comprehensive comparison of surfactant properties of a range of surfactants that has not previously been compared in this way. Furthermore, it provides insights into novel formulation of giant soap bubble toys with experimental set-ups specifically designed to test for suitability in this application.
Supervisor: Fitzsimmons-Thoss, Vera ; Lahmann, Martina Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.787483  DOI: Not available
Keywords: Soap Bubbles ; Surfactants ; Formulation ; Foam ; Soap Films
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