Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Wetting and Capillary Flow of Surfactant Solutions and Inks

von Bahr, Maria LU (2003)
Abstract
This thesis presents results of a series of experimental studies on the spreading dynamics of small drops of complex solutions on solid surfaces. The capillary flow dynamics of complex solutions have also been investigated. In the wetting experiments, water, alcohols, aqueous surfactant solutions and commercial ink-jet inks were used as test liquids, and a number of substrates, including silicate glass, hydrophobised silica, gold-alkanethiolate surfaces with controlled hydrophobicity and several different types of paper were examined with respect to their wettability.



The primary goal of these studies was to investigate the dynamic effects of surfactant adsorption and surface tension relaxation on the spreading and... (More)
This thesis presents results of a series of experimental studies on the spreading dynamics of small drops of complex solutions on solid surfaces. The capillary flow dynamics of complex solutions have also been investigated. In the wetting experiments, water, alcohols, aqueous surfactant solutions and commercial ink-jet inks were used as test liquids, and a number of substrates, including silicate glass, hydrophobised silica, gold-alkanethiolate surfaces with controlled hydrophobicity and several different types of paper were examined with respect to their wettability.



The primary goal of these studies was to investigate the dynamic effects of surfactant adsorption and surface tension relaxation on the spreading and capillary flow. Key factors, such as surface chemistry and topography of the substrates and physicochemical properties of the wetting liquids, which have been shown to control the spreading and absorption dynamics, have been identified, assessed and rationalized in the framework of the existing or newly developed theoretical models.



The drop spreading and capillary rise experiments point out that the spreading process can be divided into at least two different spreading regimes, dominated by different mechanisms and force contributions. In the first regime, occurring immediately after the drop impact, the inertia forces play a significant role together with the surface forces and gravity. The second regime is characterised by quasi-steady flow. The rate-determining step in this regime is the diffusion transport of surfactant from the bulk to the depleted liquid-vapour interface. This regime is often dominating the overall spreading process of surfactant solutions. The diffusion limitation is for instance mirrored by the fact that the rate of spreading decreases with decreasing critical micelle concentration (cmc) of the surfactant. In the case of hydrophobic substrates, the origin of the effect is the slower diffusion of micelles compared to monomers; sometimes combined with slow micellar dissociation and barriers for direct micellar adsorption.



Some of these observed phenomena are also reflected in the results of the more practical studies performed, involving e.g. inks and paper substrates. Further research is required in order to get a more complete picture although this thesis work highlights some central points with respect to paper sizing (hydrophobising) efficiency and ink spreading. (Less)
Abstract (Swedish)
Popular Abstract in Swedish

Ytaktiva ämnen (tensider) har många olika användningsområden, bl.a. är de en viktig beståndsdel i tvättmedel, hygienprodukter och en del läkemedel och livsmedel. Tensider används av en mängd olika orsaker, t.ex. kan de stabilisera lösningar och lösa upp fett. Det speciella med dessa ytaktiva ämnen är att de består av en hydrofil del som gillar vatten och en hydrofob del som ogillar vatten. Därför har de en naturlig dragningskraft att adsorbera till olika gränsytor mellan icke blandbara faser vilket orsakar en reducerad ytspänning. Det leder också till att de kan bilda aggregat i lösningen och till att lösningar av icke blandbara faser kan bilda små droppar vars ytor kläds med det ytaktiva ämnet.... (More)
Popular Abstract in Swedish

Ytaktiva ämnen (tensider) har många olika användningsområden, bl.a. är de en viktig beståndsdel i tvättmedel, hygienprodukter och en del läkemedel och livsmedel. Tensider används av en mängd olika orsaker, t.ex. kan de stabilisera lösningar och lösa upp fett. Det speciella med dessa ytaktiva ämnen är att de består av en hydrofil del som gillar vatten och en hydrofob del som ogillar vatten. Därför har de en naturlig dragningskraft att adsorbera till olika gränsytor mellan icke blandbara faser vilket orsakar en reducerad ytspänning. Det leder också till att de kan bilda aggregat i lösningen och till att lösningar av icke blandbara faser kan bilda små droppar vars ytor kläds med det ytaktiva ämnet. Aggregaten, vilket är en gruppbildning av flera molekyler, har olika struktur beroende av tensidtyp, tensidkoncentration och interaktioner mellan lösningsmedel och tensider. I vattenlösningar bildas ofta små miceller som ofta har en sfärisk eller cylindrisk struktur. I micellerna är de hydrofila huvudgrupperna ordnade utåt mot lösningen och de hydrofoba svansarna gömmer sig i micellernas inre. Om olja tillförs sväller micellerna till emulsionsdroppar. Tensiders adsorption och ytspänningssänkande förmåga möjliggör förbättrad vätning av t.ex. en vattendroppe på en annars vattenavstötande (hydrofob) yta.



I många tekniska applikationer, så som besprutning av växter och tryckning med bläckstråleskrivare (små färgdroppar sprutas på pappret med hjälp av ett litet sprutmunstycke), är tensidtillsatsers effekter på vätning och spridningsdynamik av stor betydelse. I de fall substratet är poröst, kan också effekten av tensider på absorption av vätskan vara ett viktigt steg i processen. I det här doktorandprojektet har vi studerat hur olika faktorer, så som tensidkoncentration, tensidtyp och ytans kemi och topografi, påverkar spridnings- och absorptionsförlopp. Vi har också studerat kapillärstigning av tensidlösningar i hydrofila och hydrofoba kapillärer. Studierna visar att spridningsförloppet på hydrofoba ytor kan delas upp i minst två olika intervall inom vilka olika faktorer styr dynamiken. I det första intervallet, direkt efter att droppen träffar substratet, styr tröghets-, gravitation- och kapillärkrafter. I det andra intervallet styrs spridningen av diffusion av tensid från lösningen till gränsskikten mellan droppen och luften. Tensiden transporteras sedan till gränsskiktet mellan den fasta ytan och vätskan.



De praktiska aspekterna av forskningsarbetet har framför allt varit inriktade mot tryckning med bläckstråleskrivare. Därför har vi även studerat växelverkan mellan vattenbaserade tryckfärger och papper. Det är viktigt att kunna kontrollera spridnings- och absorptionsförloppet av tryckfärgen för att erhålla en god tryckkvalitet. Genom att bättre förstå hur olika parametrar påverkar dessa processer kan problem så som blödning (olika färger blandar sig med varandra på ett oönskat sätt), taggighet av droppkanten och genomtryck minimeras. Utöver tryckning väntas forskningen vara av betydelse inom ett stort antal tillämpningsområden. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr Bain, Colin, University of Oxford, United Kingdom
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Physical chemistry, Fysikalisk kemi, AKD, ink-jet printing, paper, penetration, absorption, adsorption, hydrophobicity, nonionic, surfactant, spreading, dynamic wetting
pages
73 pages
publisher
Britt Nyström, YKI Ytkemiska Institutet AB, Box 5607, SE-114 86 Stockholm, Sweden, britt.nystrom@surfchem.kth.se,
defense location
Hörsal C, Kemicentrum, Lund
defense date
2003-06-04 14:00:00
ISBN
91-7422-022-5
language
English
LU publication?
yes
additional info
Article: PAPER I Spreading Dynamics of Surfactant SolutionsMaria von Bahr, Fredrik Tiberg and Boris ZhmudLangmuir, 1999, 15, 7069 Article: PAPER II Spreading Dynamics of Liquids and Surfactant Solutions on Partially Wettable Hydrophobic SubstratesMaria von Bahr, Fredrik Tiberg and Vassili YaminskyColloids and Surfaces A: Physicochemical and Engineering Aspects, 2001, 193, 85 Article: PAPER III Oscillations of Sessile Drops of Surfactant Solutions on Solid Substrates with Differing HydrophobicityMaria von Bahr, Fredrik Tiberg and Boris ZhmudSubmitted to Langmuir Article: PAPER IV Capillary Rise of Surfactant SolutionsFredrik Tiberg, Boris Zhmud, Karin Hallstensson and Maria von BahrPhys. Chem. Chem. Phys. , 2000, 2, 5189 Article: PAPER V Spreading and Penetration of Aqueous Solutions and Water-borne Inks in Contact with Paper and Model SubstratesMaria von Bahr, Jerzy Kizling, Boris Zhmud and Fredrik TibergAdvances in Printing Science and Technology, vol. 27-Advances in Paper and Board Performance, J Anthony Bristow, Ed., Pira International Ltd, 2001, 87 Article: PAPER VI Dynamic Wetting of AKD-Sized PapersMaria von Bahr, Rauni Seppänen, Fredrik Tiberg and Boris ZhmudSubmitted to Journal of Pulp and Paper Science Article: PAPER VII Surface Energy Characterization of AKD-Sized PapersRauni Seppänen, Maria von Bahr, Fredrik Tiberg and Boris ZhmudSubmitted to Journal of Pulp and Paper Science
id
2f67c94f-74de-425b-983d-c986b066e4e7 (old id 465918)
date added to LUP
2016-04-04 10:23:07
date last changed
2018-11-21 20:58:27
@phdthesis{2f67c94f-74de-425b-983d-c986b066e4e7,
  abstract     = {{This thesis presents results of a series of experimental studies on the spreading dynamics of small drops of complex solutions on solid surfaces. The capillary flow dynamics of complex solutions have also been investigated. In the wetting experiments, water, alcohols, aqueous surfactant solutions and commercial ink-jet inks were used as test liquids, and a number of substrates, including silicate glass, hydrophobised silica, gold-alkanethiolate surfaces with controlled hydrophobicity and several different types of paper were examined with respect to their wettability.<br/><br>
<br/><br>
The primary goal of these studies was to investigate the dynamic effects of surfactant adsorption and surface tension relaxation on the spreading and capillary flow. Key factors, such as surface chemistry and topography of the substrates and physicochemical properties of the wetting liquids, which have been shown to control the spreading and absorption dynamics, have been identified, assessed and rationalized in the framework of the existing or newly developed theoretical models.<br/><br>
<br/><br>
The drop spreading and capillary rise experiments point out that the spreading process can be divided into at least two different spreading regimes, dominated by different mechanisms and force contributions. In the first regime, occurring immediately after the drop impact, the inertia forces play a significant role together with the surface forces and gravity. The second regime is characterised by quasi-steady flow. The rate-determining step in this regime is the diffusion transport of surfactant from the bulk to the depleted liquid-vapour interface. This regime is often dominating the overall spreading process of surfactant solutions. The diffusion limitation is for instance mirrored by the fact that the rate of spreading decreases with decreasing critical micelle concentration (cmc) of the surfactant. In the case of hydrophobic substrates, the origin of the effect is the slower diffusion of micelles compared to monomers; sometimes combined with slow micellar dissociation and barriers for direct micellar adsorption.<br/><br>
<br/><br>
Some of these observed phenomena are also reflected in the results of the more practical studies performed, involving e.g. inks and paper substrates. Further research is required in order to get a more complete picture although this thesis work highlights some central points with respect to paper sizing (hydrophobising) efficiency and ink spreading.}},
  author       = {{von Bahr, Maria}},
  isbn         = {{91-7422-022-5}},
  keywords     = {{Physical chemistry; Fysikalisk kemi; AKD; ink-jet printing; paper; penetration; absorption; adsorption; hydrophobicity; nonionic; surfactant; spreading; dynamic wetting}},
  language     = {{eng}},
  publisher    = {{Britt Nyström, YKI Ytkemiska Institutet AB, Box 5607, SE-114 86 Stockholm, Sweden, britt.nystrom@surfchem.kth.se,}},
  school       = {{Lund University}},
  title        = {{Wetting and Capillary Flow of Surfactant Solutions and Inks}},
  year         = {{2003}},
}