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Spreading Exponents: Dynamics of Trisiloxane Wetting of Hydrophobic Surfaces

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Original languageEnglish
Title of host publicationDEFECTS AND DIFFUSION IN SEMICONDUCTORS: AN ANNUAL RETROSPECTIVE XII
EditorsDJ Fisher
Place of PublicationSTAFA-ZURICH
PublisherTRANS TECH PUBLICATIONS LTD
Pages139-145
Number of pages7
ISBN (Print)*****************
DOIs
Publication statusPublished - 2010

Publication series

NameDefect and Diffusion Forum Series
PublisherTRANS TECH PUBLICATIONS LTD
Volume303-304
ISSN (Print)1012-0386

Abstract

The excellent spreading and wetting behaviour of superspreader solutions has been known and extensively studied over recent years. However, explanations for spreading dynamics and accompanying mathematical models have not yet proved completely successful. Many attempts have been made to quantify the spreading exponents, but none of the models so far was able successfully to describe the whole wetting process of trisiloxane solutions, especially on hydrophobic surfaces. We have investigated the partial wetting of Silwet L-77 (R) superspreader solutions of high concentrations (well above CMC) on polymer coated substrates of varying hydrophobicity. Results obtained can be explained in terms of the Marangoni effect as the major driving force for trisiloxane enhanced spreading. A simple theory, which involves surface tension gradients governing the spreading process, was developed in order to explain the specific evolution of the drop radius and consequent decrease in the contact angle. The proposed model was found to be in excellent agreement with the experimental results. Determined equation coefficients were shown to be dependent on both surfactant concentration and the hydrophobicity of the substrate.

    Research areas

  • Hydrophobicity, Surfactant, Trisiloxane, Wetting Dynamics, SURFACTANTS, DRIVEN

ID: 18085791