Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Toward Anti-icing and De-icing Surfaces: Effects of Surface Topography and Temperature
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.ORCID iD: 0000-0002-9322-9108
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Icing severely affects society, especially in the Nordic countries. Iceaccumulation can result in critical performance problems and safetyconcerns for instance in road, air and sea transportation, transmissionlines, marine and offshore structures, wind turbines and heat exchangers.Present active ice-combating approaches possess environmental,efficiency and cost drawbacks. Thus, fabricating icephobic surfaces orcoatings impeding ice formation (anti-icing), but facilitating ice removal(de-icing) is desired. However, different conditions in the environmentduring ice formation and growth add to the complexity of the problem.An icephobic surface that works for a certain application might not be agood candidate for another. These surfaces and the challenges are infocus in this thesis.Wetting properties are important for ice formation on surfaces fromthe liquid phase (often supercooled water), where the water repellency ofthe surfaces could enhance their anti-icing effect. Considering this,different hydrophobic and superhydrophobic surfaces with differentchemistry, morphology and roughness scale were prepared. Since anyinduced wetting state hysteresis on hydrophobic surfaces could influencetheir performance, the wetting stability was investigated. In particulardynamic wetting studies of the hydrophobic surfaces revealed whatsurface characteristics benefit a stable wetting performance. Further, theeffect of temperature, particularly sub-zero temperatures, on the wettingstate of flat and nanostructured hydrophobic surfaces was investigated.This was complemented with studies of the wetting stability of sessilewater droplets on flat to micro- and multi-scale (micro-nano) roughhydrophobic samples in a freeze-thaw cycle. To be consistent with mostapplications, all temperature-controlled experiments were performed inan environmental condition facilitating frost formation. Further, antiicingproperties of hydrophobic surfaces with different topography butsimilar chemistry were studied by freezing delay measurements.A dynamic wetting study using hydrophobic samples with similarchemistry but different topography revealed that multi-scale roughnesscould benefit the wetting stability. However, when these surfaces areutilized at low temperatures the wetting hysteresis observed during acooling/heating cycle is significant. Such a temperature-inducedhysteresis is also significant on superhydrophobic surfaces. I attributethis to condensation followed by frost formation facilitating spreading of 

the supercooled water droplet. The freezing delay measurementsdemonstrate no significant effect of surface topography on anti-icingproperties of hydrophobic surfaces, however the flat surfaces showed thelongest delay. These findings are in agreement with heterogeneous icenucleation theory, suggesting preferential ice nucleation in concave sites,provided they are wetted.In the second part of this thesis, I consider the findings from theprevious part illustrating the limitations of (super)hydrophobic surfaces.The de-icing properties of hydrophilic surfaces with a hydration waterlayer, hypothesized to lubricate the interface with ice, were studied. Heretemperature-controlled shear ice adhesion measurements, down to -25oC, were performed on an adsorbed layer of a polymer, either bottle-brushstructured poly(ethylene oxide) or linear poly(ethylene oxide). The iceadhesion strength was reduced significantly on the bottle-brushstructured polymer layer, specifically at temperatures above -15 oC,whereas less adhesion reduction was observed on the layer formed by thelinear polymer. These findings are consistent with differential scanningcalorimetry (DSC) data, demonstrating that the hydration water, boundto the bottle-brush structured polymer, is in the liquid state at thetemperatures where de-icing benefit is observed. Further, continuingwith the hypothesis of the advantage of surfaces with a natural lubricantlayer for de-icing targets, I studied shear ice adhesion on the molecularlyflat basal plane of hydrophilic mica down to -35 oC. Interestingly, ultralowice adhesion strength was measured on this surface. I relate this to theproposed distinct structure of the first ice-like but fluid water layer onmica, with no free OH groups, followed by more bulk liquid-like layers.This combined with the molecularly smooth nature of mica results in aperfect plane for ice sliding.

Abstract [sv]

Isbildning har en stark inverkan på samhället, speciellt i de nordiskaländerna. Isuppbyggnad kan resultera i kritiska prestandaproblem ochsäkerhetsrisker inom t.ex. väg-, luft-, och sjötransport, kraftledningar,marina- och offshorestrukturer, vindkraftverk och värmeväxlare.Nuvarande aktiva isbekämpningsmetoder uppvisar brister i avseende påmiljö, effektivitet och kostnad. Det finns därmed ett behov av attframställa ytor eller ytbeläggningar som förhindrar isbildning (antiisning)eller underlättar borttagandet av redan bildad is (avisning). Dockkompliceras problemet av de många olika förhållanden under vilka is kanbildas. En beläggning som fungerar för en viss tillämpning behöver intenödvändigtvis vara en bra kandidat för en annan. Dessa ytor ochutmaningar relaterade till dem är i fokus i denna avhandling.Vätningsegenskaper är viktiga för isbildning på ytor från vätskefas(ofta underkylt vatten), och det har visats att vattenavstötande ytor i vissasammanhang kan motverka isbildning. Med detta i åtanke framställdesolika hydrofoba och superhydrofoba ytor, med varierande kemi,morfologi och ytråhet. Eftersom en förändring i de hydrofoba ytornasvätningsegenskaper kan påverka deras funktion studerades vätningsstabilitetenför dessa ytor. I synnerhet dynamiska vätningsstudier av dehydrofoba ytorna avslöjade vilka ytegenskaper som är fördelaktiga förvätningsstabiliteten. Vidare studerades hur temperaturen, särskilt undernoll grader, påverkar vätningstillståndet på släta och nanostruktureradehydrofoba ytor. Arbetet kompletterades med studier av vätningsstabilitetenför vattendroppar på släta samt mikro- och multistrukturerade(mikro-nano) hydrofoba ytor under flera frysningsupptiningscykler.För att vara i linje med de flesta tillämpningar, utfördesalla temperaturkontrollerade mätningar i en miljö där frost kunde bildaspå ytorna. Anti-isegenskaperna hos de hydrofoba ytorna med varierandetopografi men samma kemi studerades vidare genom att studera hur långtid det dröjde innan en vattendroppe på ytan fryste vid en visstemperatur.De dynamiska vätningsstudierna på hydrofoba ytor med samma kemimen olika topografi avslöjade att en ytråhet på flera längdskalor kan haen positiv inverkan på vätningsstabiliteten. När dessa ytor är exponeradeför låga temperaturer är dock vätningshysteresen under en nedkylnings-/uppvärmnings-cykel significant. Den temperatur-inducerade hysteresenär också betydande för superhydrofoba ytor. Detta tillskriver jag 

kondensation på ytan som följs av frostbildning, vilket i sin tur möjliggörspridning av den underkylda vattendroppen på ytan. Mätning avfördröjningen i frysningsförloppet påvisade ingen betydande effekt avyttopografin för hydrofoba ytor, men släta hydrofoba ytor uppvisade denlängsta fördröjningen. Dessa resultat är i överensstämmelse med rådandeheterogen iskärnbildningsteori, som visar på fördelaktig iskärnbildningpå konkava delar av ytan, förutsatt att dessa väts.I den andra delen av avhandlingen utnyttjar jag observationerna frånden första delen vilka illustrerade begränsningarna för superhydrofobaytor, och söker en annan lösning. Avisningsegenskaper för hydrofilastarkt hydratiserade ytor studerades, med hypotesen att hydratiseringkan smörja gränsskiktet med is. Temperatur-kontrolleradeisadhesionsmätningar ned till -25 °C utfördes på adsorberade skikt av enpolymer med många sidokedjor av polyetylenoxid (”bottle-brush”), såvälsom på ett skikt av linjär polyetylenoxid. Isadhesionen blev kraftigtreducerad på ”bottle-brush”-polymeren, speciellt vid temperaturer högreän -15°C. Däremot kunde knappast ingen minskad isadhesion observerasför den linjära polymeren. Dessa observationer överensstämmer meddifferentialskanningskalorimetri (DSC) data, som visar att dethydratiserade vattenskiktet, vilket är bundet till ”bottle-brush”-polymeren, är i vätskeform vid de temperaturer där avisningsfördelar ärobserverade. För att vidare undersöka hypotesen att det vore fördelaktigtmed ett naturligt smörjande skikt på ytan för att uppnå godaavisningsegenskaper, utförde jag isadhesionsmätningar på molekylärtsläta glimmerytor ner till -35 °C. Intressant nog uppmättes extremt lågisadhesion på denna yta. Detta relaterar jag till den föreslagna utprägladehydratiseringsstrukturen, bestående av ett första is-liknande vattenskiktutan fria OH-grupper, följt av ett mer bulkliknande skikt. Detta ikombination med den molekylärt släta naturen hos glimmer resulterar iett perfekt plan för isen att glida på.

Place, publisher, year, edition, pages
Stokcholm: KTH Royal Institute of Technology, 2016. , xviii, 80 p.
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2016:11
Keyword [en]
anti-icing, topography, supercooled water, wetting hysteresis, superhydrophobic, contact angle, nucleation, freezing delay, de-icing, ice adhesion, hydration water, liquid-like layer, smooth, lubrication
Keyword [sv]
anti-is, topografi, underkylt vatten, vätningshysteres, superhydrofob, kontaktvinkel, kärnbildning, avisning, isadhesion, hydrerat vatten, vätskeliknande skikt, smörjning
National Category
Chemical Engineering
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-186187ISBN: 978-91-7595-901-6 (print)OAI: oai:DiVA.org:kth-186187DiVA: diva2:926048
Public defence
2016-05-27, F3, Lindstedtsvägen 26, KTH Campus, Stockholm, 10:00 (English)
Opponent
Supervisors
Projects
TopNano
Note

QC 20160504

Available from: 2016-05-04 Created: 2016-05-03 Last updated: 2016-05-10Bibliographically approved
List of papers
1. Hydrophobic Surfaces: Topography Effects on Wetting by Supercooled Water and Freezing Delay
Open this publication in new window or tab >>Hydrophobic Surfaces: Topography Effects on Wetting by Supercooled Water and Freezing Delay
Show others...
2013 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, no 42, 21752-21762 p.Article in journal (Refereed) Published
Abstract [en]

Hydrophobicity, and in particular superhydrophobicity, has been extensively considered to promote ice-phobicity. Dynamic contact angle measurements above 0 degrees C have been widely used to evaluate the water repellency. However, it is the wetting properties of supercooled water at subzero temperatures and the derived work of adhesion that are important for applications dealing with icing. In this work we address this issue by determining the temperature-dependent dynamic contact angle of microliter-sized water droplets on a smooth hydrophobic and a superhydrophobic surface with similar surface chemistry. The data highlight how the work of adhesion of water in the temperature interval from about 25 degrees C to below -10 degrees C is affected by surface topography. A marked decrease in contact angle on the superhydrophobic surface is observed with decreasing temperature, and we attribute this to condensation below the dew point. In contrast, no significant wetting transition is observed on the smooth hydrophobic surface. The freezing temperature and the freezing delay time were determined for water droplets resting on a range of surfaces with similar chemistry but different topography, including smooth and rough surfaces in either the Wenzel or the Cassie-Baxter state as characterized by water contact angle measurements at room temperature. We find that the water freezing delay time is not significantly affected by the surface topography and discuss this finding within the classical theory of heterogeneous nucleation.

Keyword
Ice Adhesion, Superhydrophobic Surfaces, Heterogeneous Nucleation, Patterned Surfaces, Recent Progress, Wettability, Repellent, Polymers, Coatings, State
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-136504 (URN)10.1021/jp404396m (DOI)000326260000015 ()2-s2.0-84886675722 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20131210

Available from: 2013-12-10 Created: 2013-12-05 Last updated: 2017-12-06Bibliographically approved
2. Wetting hysteresis induced by temperature changes: Supercooled water on hydrophobic surfaces
Open this publication in new window or tab >>Wetting hysteresis induced by temperature changes: Supercooled water on hydrophobic surfaces
Show others...
2016 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 468, 21-33 p.Article in journal (Refereed) Published
Abstract [en]

The state and stability of supercooled water on (super)hydrophobic surfaces is crucial for low temperature applications and it will affect anti-icing and de-icing properties. Surface characteristics such as topography and chemistry are expected to affect wetting hysteresis during temperature cycling experiments, and also the freezing delay of supercooled water. We utilized stochastically rough wood surfaces that were further modified to render them hydrophobic or superhydrophobic. Liquid flame spraying (LFS) was utilized to create a multi-scale roughness by depositing titanium dioxide nanoparticles. The coating was subsequently made non-polar by applying a thin plasma polymer layer. As flat reference samples modified silica surfaces with similar chemistries were utilized. With these substrates we test the hypothesis that superhydrophobic surfaces also should retard ice formation. Wetting hysteresis was evaluated using contact angle measurements during a freeze-thaw cycle from room temperature to freezing occurrence at -7 degrees C, and then back to room temperature. Further, the delay in freezing of supercooled water droplets was studied at temperatures of -4 degrees C and -7 degrees C. The hysteresis in contact angle observed during a cooling-heating cycle is found to be small on flat hydrophobic surfaces. However, significant changes in contact angles during a cooling-heating cycle are observed on the rough surfaces, with a higher contact angle observed on cooling compared to during the subsequent heating. Condensation and subsequent frost formation at sub-zero temperatures induce the hysteresis. The freezing delay data show that the flat surface is more efficient in enhancing the freezing delay than the rougher surfaces, which can be rationalized considering heterogeneous nucleation theory. Thus, our data suggests that molecular flat surfaces, rather than rough superhydrophobic surfaces, are beneficial for retarding ice formation under conditions that allow condensation and frost formation to occur. 

Place, publisher, year, edition, pages
Elsevier, 2016
Keyword
Wetting hysteresis, Contact angle, Supercooled water, Morphology, Hydrophobization, Multi-scale roughness, Wood, Superhydrophobicity, Liquid flame spray (LFS), Plasma polymerization
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-184947 (URN)10.1016/j.jcis.2016.01.040 (DOI)000371279900003 ()26821148 (PubMedID)2-s2.0-84955276633 (Scopus ID)
Funder
Swedish Research Council, 2014-172
Note

QC 20160407

Available from: 2016-04-07 Created: 2016-04-07 Last updated: 2017-11-30Bibliographically approved
3. Hydrophobisation of wood surfaces by combining liquid flame spray (LFS)and plasma treatment: dynamic wetting properties
Open this publication in new window or tab >>Hydrophobisation of wood surfaces by combining liquid flame spray (LFS)and plasma treatment: dynamic wetting properties
Show others...
2016 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 70, no 6, 527-537 p.Article in journal (Refereed) Published
Abstract [en]

The hydrophilic nature of wood surfaces is a major cause for water uptake and subsequent biological degradation and dimensional changes. In the present paper, a thin transparent superhydrophobic layer on pine veneer surfaces has been created for controlling surface wettability and water repellency. This effect was achieved by means of the liquid flame spray (LFS) technique, in the course of which nanoparticulate titanium dioxide (TiO2) was brought to the surface, followed by plasma polymerisation. Plasma polymerised perfluorohexane (PFH) or hexamethyldisiloxane (HMDSO) were then deposited onto the LFS-treated wood surfaces. The same treatment systems were applied to silicon wafers so as to have well-defined reference surfaces. The dynamic wettability was studied by the multicycle Wilhelmy plate method, resulting in advancing and receding contact angles as well as sorption behaviour of the samples during repeated wetting cycles in water. Atomic force microscopy (AFM) and Xray photoelectron spectroscopy (XPS) were employed to characterise the topography and surface chemical compositions and to elucidate the question how the morphology of the nanoparticles and plasma affect the wetting behaviour. A multi-scale roughness (micro-nano roughness) was found and this enhanced the forced wetting durability via a superhydrophobic effect on the surface, which was stable even after repeated wetting cycles. The hydrophobic effect of this approach was higher compared to that of plasma modified surfaces with their micro-scale modification.

Place, publisher, year, edition, pages
Walter de Gruyter, 2016
Keyword
contact angle (CA); dynamic wetting, hydrophobisation; hexamethyldisiloxane (HMDSO); liquid flame spray (LFS); multi-scale roughness; nano-sized metal oxide (TiO2); perfluorohexane (PFH); plasma polymerisation; superhydrophobicity; Wilhelmy plate method; wood.
National Category
Wood Science
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-175873 (URN)10.1515/hf-2015-0148 (DOI)000376680300006 ()2-s2.0-84973442118 (Scopus ID)
Funder
Swedish Research Council Formas, 2014-172
Note

QC 20161101

Available from: 2015-10-23 Created: 2015-10-23 Last updated: 2017-12-01Bibliographically approved
4. Temperature-Dependent Deicing Properties of ElectrostaticallyAnchored Branched Brush Layers of Poly(ethylene oxide)
Open this publication in new window or tab >>Temperature-Dependent Deicing Properties of ElectrostaticallyAnchored Branched Brush Layers of Poly(ethylene oxide)
Show others...
2016 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 17, 4194-4202 p.Article in journal (Refereed) Published
Abstract [en]

The hydration water of hydrophilic polymersfreezes at subzero temperatures. The adsorption of suchpolymers will result in a hydrophilic surface layer that stronglybinds water. Provided this interfacial hydration water remainsliquidlike at subzero temperatures, its presence could possiblyreduce ice adhesion, in particular, if the liquidlike layer isthicker than or comparable to the surface roughness. Toexplore this idea, a diblock copolymer, having one branchedbottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. Theshear ice adhesion strength on such polymer-coated surfaces was investigated down to −25 °C using a homebuilt device. Inaddition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branchedbottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, attemperatures above −15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer.Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of waterinteracting with branched and linear poly(ethylene oxide) (with hydration water melting points of about −18 and −10 °C,respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branchedbottle-brush structured poly(ethylene oxide) at −10 °C, whereas no significant adhesion reduction was obtained with linearpoly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottlebrushstructured poly(ethylene oxide), which, in the bulk, does not freeze until −18 °C.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2016
National Category
Polymer Technologies Manufacturing, Surface and Joining Technology
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-186185 (URN)10.1021/acs.langmuir.6b00671 (DOI)000375520800008 ()2-s2.0-84968764173 (Scopus ID)
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research
Note

QC 20160504

Available from: 2016-05-03 Created: 2016-05-03 Last updated: 2017-11-30Bibliographically approved
5. Ultralow ice adhesion on hydrophilic and molecularly smooth mica surfaces
Open this publication in new window or tab >>Ultralow ice adhesion on hydrophilic and molecularly smooth mica surfaces
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Despite much research on designing surfaces for combating icing, no permanent solution has been achievedusing solid materials. Inspired by the slippery surface of ice, attributed to the presence of a quasi-liquid layeracting as a natural lubricant, we hypothesize that flat hydrophilic surfaces with a hydration layer remaining inthe liquid-like state at the solid-ice interface could result in low ice adhesion. Utilizing temperature-controlledice adhesion measurements on the molecularly smooth basal plane of muscovite mica, we observed the lowestreported ice adhesion on solid surfaces down to temperatures of -35 ºC. The ice adhesion is dramatically higheron flat hydrophilic silica surfaces. We discuss these findings in terms of what is known about mica-water andmica-ice interactions.

National Category
Polymer Technologies Manufacturing, Surface and Joining Technology
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-186186 (URN)
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research
Note

QC 20160504

Available from: 2016-05-03 Created: 2016-05-03 Last updated: 2016-05-04Bibliographically approved

Open Access in DiVA

fulltext(2259 kB)349 downloads
File information
File name FULLTEXT01.pdfFile size 2259 kBChecksum SHA-512
c823a6edaa25f266e335e95e79abff20094c8173bc6caacf07312214bfb78eea1f6d26dee59a3ba698339309678177bfb0217415d1219289f02bc78bdb45e5b4
Type fulltextMimetype application/pdf

Authority records BETA

Heydari, Golrokh

Search in DiVA

By author/editor
Heydari, Golrokh
By organisation
Surface and Corrosion Science
Chemical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 349 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1253 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf