Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants
Recent measurements of the surface viscoelasticity of liquid surfaces with adsorbed surfactant using surface light scattering have yielded negative dilational viscosities (ε’ < 0). In this paper, we present a physical explanation for this phenomenon by constructing a molecularly based theory for...
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| Format: | Article |
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Universiti Kebangsaan Malaysia
1999
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| Online Access: | http://journalarticle.ukm.my/3771/ |
| _version_ | 1848810296915787776 |
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| author | Buzza, D.M.A. |
| author_facet | Buzza, D.M.A. |
| author_sort | Buzza, D.M.A. |
| building | UKM Institutional Repository |
| collection | Online Access |
| description | Recent measurements of the surface viscoelasticity of liquid surfaces with adsorbed surfactant using surface light scattering have yielded negative dilational viscosities (ε’ < 0). In this paper, we present a physical explanation for this phenomenon by constructing a molecularly based theory for the interfacial viscoelasticity of an insoluble surfactant monolayer. Using the interfacial viscoelasticity, we then calculate the resultant surface light scattering from the interface. Our microscopic theory predicts the presence of two additional surface elastic constants neglected in current treatments, namely a bending modulus, κ and a coupling constant λ. We show that for thick monolayers, the coupling constant λ can lead to apparent negative values of ε’. This is the first time that this result has been explained for insoluble monolayers using a physically realistic model. |
| first_indexed | 2025-11-14T23:28:16Z |
| format | Article |
| id | oai:generic.eprints.org:3771 |
| institution | Universiti Kebangasaan Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T23:28:16Z |
| publishDate | 1999 |
| publisher | Universiti Kebangsaan Malaysia |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | oai:generic.eprints.org:37712012-05-02T09:41:20Z http://journalarticle.ukm.my/3771/ Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants Buzza, D.M.A. Recent measurements of the surface viscoelasticity of liquid surfaces with adsorbed surfactant using surface light scattering have yielded negative dilational viscosities (ε’ < 0). In this paper, we present a physical explanation for this phenomenon by constructing a molecularly based theory for the interfacial viscoelasticity of an insoluble surfactant monolayer. Using the interfacial viscoelasticity, we then calculate the resultant surface light scattering from the interface. Our microscopic theory predicts the presence of two additional surface elastic constants neglected in current treatments, namely a bending modulus, κ and a coupling constant λ. We show that for thick monolayers, the coupling constant λ can lead to apparent negative values of ε’. This is the first time that this result has been explained for insoluble monolayers using a physically realistic model. Universiti Kebangsaan Malaysia 1999 Article PeerReviewed Buzza, D.M.A. (1999) Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants. Sains Malaysiana, 28 . pp. 101-118. ISSN 0126-6039 http://www.ukm.my/jsm/english_journals/vol28_1999/vol28_99page101-118.html |
| spellingShingle | Buzza, D.M.A. Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| title | Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| title_full | Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| title_fullStr | Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| title_full_unstemmed | Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| title_short | Negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| title_sort | negative surface viscosities in fluid-fluid interfaces with adsorbed insoluble surfactants |
| url | http://journalarticle.ukm.my/3771/ http://journalarticle.ukm.my/3771/ |