Homecare products are in demand all over the world. As such the formulations need to be able to withstand extreme weather, such as cold climates.

As the temperature of a surfactant system (e.g. dish liquid) is lowered some precipitated crystals may be visualized, especially if the temperature is below the Krafft point of the surfactant system

Summerton, Emily

University of Birmingham Research Archive, E-papers Repository

Introduction  • Homecare products are in demand all over the world. As such the formulations need to be able to withstand  extreme weather, such as cold climates.   • As the temperature of a surfactant system (e.g. dish liquid) is lowered some precipitated crystals may be visualized, especially if the temperature is below the Krafft point of the surfactant system.  More than just a bottle by your sink!   Emily Summerton, Georgina Zimbitas, Melanie Britton and Serafim Bakalis Chemical Engineering Department, University of Birmingham, Edgbaston, Birmingham, B15 2TT Bottle shape Types of surfaces Cooling rate Volume Addition of seed particles Composition Time after droplet added (seconds):  A. 20 B. 40 C. 60  D. 80 A C D B Temperature Bottle material Concentration Aims and Objectives     Use scientific techniques to study and monitor crystallisation of surfactant based formulations such as dish liquid and simple model systems.   Consider how the factors below affect the rate and shape of crystallisation:  Experimental Setup  • The following equipment (Figure 1) was utilised in order to expose a complex surfactant system to sub zero temperatures.   • At set intervals after crystallisation,  images are acquired  and used  to analyse growth rate.   Risk of crystallisation      Observations  In drop systems, growth originates from the outer circumference. Two factors may be responsible for this observation: 1) Surface tension  2) Temperature  differences   Figure 1: Experimental set up for microscopic crystal growth Initial Crystal Growth Study  Next Steps  • Chemical and spectroscopic analysis on crystal surfactant structure and composition e.g. DSC, (cryo) SEM, Raman.  • Determine how the cooling rate affects microscopic crystal formation.   Figure 2: Crystal growth time series images  Long term goal is to minimise the risk of crystallisation  and  subsequently improve profits and reduce waste. Information presented on this poster is confidential and must not be disseminated outside the university. References: 1. Amante, J.C., J.F. Scamehorn, and J.H. Harwell, Precipitation of mixtures of anionic and cationic surfactants.  Journal of Colloid and Interface Science, 1991. 144(1): p. 243-253. 2. Smith, L.A., et al., Crystallisation of sodium dodecyl sulphate from aqueous solution: phase identification, crystal morphology, surface chemistry and kinetic interface roughening. Journal of Crystal Growth, 2004. 263(1-4):          p. 480-490. 

More than just a bottle by your sink!

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University of Birmingham Research Archive, E-papers Repository