Multiscale dissipative mechanisms and hierarchical surfaces : friction, superhydrophobicity, and biomimetics

285 Pages·2008·4.08 MB·English

by  Mikhail NosonovskiiМ†, Bharat Bhushan

NANOSCIENCE AND TECHNOLOGY
NANOSCIENCE AND TECHNOLOGY
SeriesEditors:
P.Avouris B.Bhushan D.Bimberg K.vonKlitzing H.Sakaki R.Wiesendanger
TheseriesNanoScienceandTechnologyisfocusedonthefascinatingnano-world,meso-
scopicphysics,analysiswithatomicresolution,nanoandquantum-effectdevices,nano-
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velopmentsinthisemergingdisciplinearecoveredbycomprehensiveandtimelybooks.
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ingexpertsinthefield.Thesebookswillappealtoresearchers,engineers,andadvanced
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AtomicForceMicroscopy,Scanning ChargeMigrationinDNA
NearfieldOpticalMicroscopy PerspectivesfromPhysics,Chemistry,
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Application Editor:T.Chakraborty
toRoughandNaturalSurfaces
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AppliedScanningProbeMethodsVI Editor:O.Schmidt
Characterization
AppliedScanningProbeMethodsVIII
Editors:B.BhushanandS.Kawata
ScanningProbeMicroscopy
AppliedScanningProbeMethodsVII Techniques
Biomimetics Editors:B.Bhushan,H.Fuchs,
andIndustrialApplications andM.Tomitori
Editors:B.BhushanandH.Fuchs
AppliedScanningProbeMethodsIX
Roadmap
Characterization
ofScanningProbeMicroscopy
Editors:B.Bhushan,H.Fuchs,
Editors:S.Morita andM.Tomitori
Nanocatalysis
AppliedScanningProbeMethodsX
Editors:U.HeizandU.Landman
Biomimetics
Nanostructures andIndustrialApplications
FabricationandAnalysis Editors:B.Bhushan,H.Fuchs,
Editor:H.Nejo andM.Tomitori
FundamentalsofFrictionandWear SemiconductorNanostructures
ontheNanoscale Editor:D.Bimberg
Editors:E.GneccoandE.Meyer
MultiscaleDissipativeMechanisms
NanostructuredSoftMatter andHierarchicalSurfaces
Experiment,Theory,Simulation Friction,Superhydrophobicity,
andPerspectives andBiomimetics
Editor:A.V.Zvelindovsky ByM.NosonovskyandB.Bhushan
Michael Nosonovsky
Bharat Bhushan
Multiscale
Dissipative Mechanisms
and Hierarchical Surfaces
Friction, Superhydrophobicity,
and Biomimetics
With112Figures
Dr.MichaelNosonovsky
StevensInstituteofTechnology,DepartmentofMechanicalEngineering
CastlePointofHudson,Hoboken,NJ07030,USA
E-mail:[email protected]
ProfessorDr.BharatBhushan
OhioStateUniversity
NanoprobeLaboratoryforBio-&NanotechnologyandBiomimetics(NLB2)
201W.19thAvenue,Columbus,OH43210,USA
E-mail:[email protected]
SeriesEditors:
ProfessorDr.PhaedonAvouris ProfessorDr.,Dres.h.c.KlausvonKlitzing
IBMResearchDivision Max-Planck-Institut
NanometerScaleScience&Technology fürFestkörperforschung
ThomasJ.WatsonResearchCenter Heisenbergstr.1
P.O.Box218 70569Stuttgart,Germany
YorktownHeights,NY10598,USA
ProfessorDr.BharatBhushan ProfessorHiroyukiSakaki
OhioStateUniversity UniversityofTokyo
NanoprobeLaboratoryforBio-& InstituteofIndustrialScience
NanotechnologyandBiomimetics(NLB2) 4-6-1Komaba,Meguro-ku
201W.19thAvenue Tokyo153-8505,Japan
Columbus,OH43210,USA
ProfessorDr.DieterBimberg ProfessorDr.RolandWiesendanger
TUBerlin,FakultätMathematik/ InstitutfürAngewandtePhysik
Naturwissenschaften UniversitätHamburg
InstitutfürFestkörperphysik Jungiusstr.11
Hardenbergstr.36 20355Hamburg,Germany
10623Berlin,Germany
ISSN1434-4904
ISBN978-3-540-78424-1SpringerBerlinHeidelbergNewYork
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Preface
Thisbookisintendedtoserveasanintroductiontoadevelopingfieldofengineering
biologicallyinspiredsurfaceswithhierarchicalstructures.Recentadvancesinmicro-
and nanoscience reveal a growing number of surfaces with hierarchical structures,
that is, with nanoscale details superimposed on the microscale details, sometimes
superimposedonlargermacroscaledetails.Suchhierarchicalstructuresarerequired
for certain functions, such as achieving extremely low or extremely high friction
andadhesion,andwater-repellency.Friction,adhesion,andwettingarecomplicated
processes, which involve effects at different scale levels with different characteris-
tic scale lengths. Engineers are trying to mimic nature in order to design artificial
surfaceswithdesirableproperties,referredtoasbioinspiredorbiomimeticsurfaces.
Thefieldisreferredtoasbiomimetics.
Our purpose is, first of all, to present the qualitative picture of physical phe-
nomena, rather than to provide rigorous mathematical derivations or many tech-
nical details, which may be found in the references. We concentrate upon such
issuesasscaleanddimension,linearityandnonlinearity,andthefundamentalphys-
ical mechanisms and effects involved in the phenomena under consideration. This
allows a reader who is not familiar with the field or not a specialist in surface sci-
encetograspquicklytheessenceoftheprocessesandtheissuesdiscussed.Onthe
other hand, we felt it necessary to present a brief discussion of modern analytical
andexperimentalmethodsandapproachesusedinmesoscaleandmultiscalescience
and recent trends in the development of the surface science and multiscale model-
ing.
The book is divided into three parts. The first part is devoted to the solid–solid
dryfriction,whichisatraditionalsubjectofstudyoftribology.Inthispart,wecover
topics such as the statistical and fractal characterization of rough random surfaces
and solid–solid contact, which have been developed over the past 30 years and are
usedwidelyinengineering.Wediscussthemeasurementtechniquesandequipment
thatallowsscientiststostudysurfacesatnanoscaleresolution—includingscanning
probemicroscopy,whichemergedintheearly1980s.Ouremphasisisonthemulti-
scale,hierarchicalnatureofthedissipationmechanisms,whicharebecomingevident
asmoreandmoredataaboutthenanoscalefrictionareobtained.
vi Preface
In the second part of the book, we study the solid–liquid friction and wetting
of rough surfaces, as well as related capillary phenomena. Rough water-repellent
orsuperhydrophobicsurfaces,whichareoftenfoundinbiologicalsystems,inmany
caseshaveacomplicatedhierarchicalstructurethatisrequiredforcertainfunctional-
ity,suchasnonwetting,lowsolid–liquidfriction,highfrictionandadhesion.Leaves
ofwater-repellentplants,suchasthelotus,constituteanexampleofthesesurfaces.
Their surfaces are extremely hydrophobic, and a droplet can flow over them with
lowenergydissipation.However,themechanismsinvolvedintheprocessarecom-
plicated and have different characteristic length scales, so the surfaces should also
behierarchical.Roughness-inducedsuperhydrophobicityandthe“lotus-effect”have
beenstudiedextensivelyduringthepastdecadewiththenumberofarticlesinpeer-
reviewedjournalsgrowingexponentiallysincetheearly2000s.Thisisbecausethe
technologythatallowsustoproduceanartificiallotusleafsurfacebecameavailable.
However,therehasbeennosinglebookthatcoversthetheoryofsuperhydrophobic-
ity, the observation and characterization of natural superhydrophobic surfaces, and
the methods of production and characterization of artificial superhydrophobic sur-
faces.Thisbook’spurposeistocoverthisgapintheliterature.
Another example of natural hierarchical surfaces is the gecko foot, which has
an ability to achieve very high adhesion (so that it can climb upon a vertical wall)
and detach from the surface at will. These abilities are known as smart adhesion.
Smart adhesion, along with other functional hierarchical biological surfaces, such
as thesharkskin andthe motheye,are studiedin thethirdpartof thebook.These
functional biological surfaces inspired engineers to design artificial surfaces with
similarproperties.Biomimetichierarchicalsurfacesarediscussedinthatpartofthe
book along with other practical issues, such as techniques to experimentally study
thewettingofroughsurfaces.
The book is written with a broad multidisciplinary readership in mind. It can
serveasasupplementarytextbookforagraduatecourseinsurfacescience,tribology,
ornanotechnology.Itcanbeusedbyengineersandscientistswhowanttofamiliarize
themselves with the basic concepts of nanotribology and biologically inspired sur-
faces.Theauthorshopethatthebookwillbeusefultoabroadaudienceofreaders
fromvariousbackgrounds.
Wethankourcolleagues,Dr.StephenM.Hsu,Dr.Seung-HoYangandDr.Huan
ZhangfromtheNationalInstituteofStandardsandTechnology(NIST)inGaithers-
burg,MD;Mr.Yong-ChaeJungandDr.Tae-WanKimattheOhioStateUniversity
(OSU)inColumbus,OH;andMs.CaterinaRunyon-SpearsfromtheOSUandothers
whohelpedinpreparationofthisbook.Thebookwaswrittenpartiallywhileoneof
theauthors,Dr.MichaelNosonovsky,wasaNationalResearchCouncilpostdoctoral
research fellow at NIST. However, none of the equipment, results, or commercial
products mentioned or presented in this book should be treated as endorsed or ap-
provedbyNIST.
November2007 MichaelNosonovsky
BharatBhushan
Contents
Preface............................................................ v
Nomenclature...................................................... xiii
Glossary .......................................................... xv
Abbreviations...................................................... xvii
PartI SurfaceRoughnessandHierarchicalFrictionMechanisms
1 Introduction................................................... 3
1.1 SurfacesandSurfaceFreeEnergy............................. 3
1.2 Mesoscale................................................. 5
1.3 Hierarchy ................................................. 7
1.4 Dissipation................................................ 7
1.5 Tribology ................................................. 9
1.6 Biomimetics:FromEngineeringtoBiologyandBack ............ 11
2 RoughSurfaceTopography ..................................... 13
2.1 RoughSurfaceCharacterization .............................. 13
2.2 StatisticalAnalysisofRandomSurfaceRoughness .............. 17
2.3 FractalSurfaceRoughness................................... 20
2.4 ContactofRoughSolidSurfaces.............................. 23
2.5 SurfaceModification........................................ 25
2.5.1 SurfaceTexturing.................................... 25
2.5.2 LayerDeposition .................................... 25
2.6 Summary ................................................. 26
3 MechanismsofDryFriction,TheirScalingandLinearProperties ... 27
3.1 ApproachestotheMultiscaleNatureofFriction................. 28
3.2 MechanismsofDryFriction ................................. 31
3.2.1 AdhesiveFriction.................................... 31
viii Contents
3.2.2 DeformationofAsperities............................. 38
3.2.3 PlasticYield ........................................ 39
3.2.4 Fracture ............................................ 39
3.2.5 RatchetandCobblestoneMechanisms................... 39
3.2.6 “ThirdBody”Mechanism ............................. 40
3.2.7 Discussion.......................................... 40
3.3 FrictionasaLinearPhenomenon ............................. 40
3.3.1 Friction,ControlledbyRealAreaofContact ............. 41
3.3.2 FrictionControlledbyAverageSurfaceSlope ............ 43
3.3.3 OtherExplanationsoftheLinearityofFriction ........... 44
3.3.4 Linearityandthe“SmallParameter” .................... 45
3.4 Summary ................................................. 45
4 FrictionasaNonlinearHierarchicalPhenomenon ................. 47
4.1 NonlinearEffectsinDryFriction ............................. 47
4.1.1 NonlinearityoftheAmontons–CoulombRule ............ 47
4.1.2 DynamicInstabilitiesAssociatedwiththeNonlinearity .... 48
4.1.3 Velocity-DependenceandDynamicFriction.............. 49
4.1.4 Interdependence of the Load-, Size-, and Velocity-
DependenceoftheCoefficientofFriction................ 50
4.1.5 Stick–SlipMotion ................................... 51
4.1.6 Self-OrganizedCriticality ............................. 52
4.2 NonlinearityandHierarchy .................................. 53
4.3 Heterogeneity,HierarchyandEnergyDissipation................ 55
4.3.1 Idealvs.RealContactSituations ....................... 55
4.3.2 MeasureofInhomogeneityandDissipationatVarious
HierarchyLevels .................................... 55
4.3.3 Order-ParameterandMesoscopicFunctional ............. 59
4.3.4 KineticsoftheAtomic-ScaleFriction ................... 59
4.4 MappingofFrictionatVariousHierarchyLevels ................ 61
4.5 Summary ................................................. 62
PartII Solid–LiquidFrictionandSuperhydrophobicity
5 Solid–LiquidInteractionandCapillaryEffects .................... 65
5.1 ThreePhaseStatesofMatter ................................. 65
5.2 PhaseEquilibriumandStability .............................. 67
5.3 WaterPhaseDiagramattheNanoscale......................... 69
5.4 SurfaceFreeEnergyandtheLaplaceEquation .................. 72
5.5 ContactAngleandtheYoungEquation ........................ 73
5.6 Kelvin’sEquation .......................................... 76
5.7 CapillaryEffectsandStabilityIssues .......................... 77
5.8 Summary ................................................. 79
Contents ix
6 Roughness-InducedSuperhydrophobicity......................... 81
6.1 ThePhenomenonofSuperhydrophobicity ...................... 81
6.2 ContactAngleAnalysis ..................................... 85
6.3 HeterogeneousSurfacesandWenzelandCassieEquations ........ 86
6.3.1 ContactAnglewithaRoughandHeterogeneousSurfaces .. 86
6.3.2 TheCassie–BaxterEquation........................... 87
6.3.3 LimitationsoftheWenzelandCassieEquations .......... 90
6.3.4 RangeofApplicabilityoftheWenzelandCassieEquations. 92
6.4 CalculationoftheContactAngleforSelectedSurfaces ........... 96
6.4.1 Two-DimensionalPeriodicProfiles ..................... 96
6.4.2 Three-DimensionalSurfaces........................... 100
6.4.3 SurfaceOptimizationforMaximumContactAngle........ 105
6.5 ContactAngleHysteresis.................................... 107
6.5.1 OriginoftheContactAngleHysteresis .................. 107
6.5.2 PinningoftheTripleLine ............................. 109
6.5.3 ContactAngleHysteresisandtheAdhesionHysteresis..... 110
6.6 Summary ................................................. 112
7 StabilityoftheCompositeInterface,RoughnessandMeniscusForce. 115
7.1 DestabilizationoftheCompositeInterface...................... 115
7.1.1 DestabilizationDuetoCapillaryandGravitationalWaves .. 116
7.1.2 ProbabilisticModel .................................. 121
7.1.3 AnalysisofRoughProfiles ............................ 122
7.1.4 EffectofDropletWeight .............................. 123
7.2 ContactAnglewithThree-DimensionalSolidHarmonicSurface ... 126
7.2.1 Three-DimensionalHarmonicRoughSurface ............ 126
7.2.2 CalculationsoftheContactAreas ...................... 128
7.2.3 MetastableStates .................................... 129
7.2.4 OverallContactAngle................................ 130
7.2.5 DiscussionofResults................................. 131
7.2.6 TheSimilarityofBubblesandDroplets.................. 133
7.3 CapillaryAdhesionForceDuetotheMeniscus.................. 134
7.3.1 SphereinContactwithaSmoothSurface ................ 134
7.3.2 Multiple-AsperityContact............................. 136
7.4 RoughnessOptimization .................................... 137
7.5 EffectoftheHierarchicalRoughness .......................... 141
7.5.1 HierarchicalRoughness............................... 141
7.5.2 Stability of a Composite Interface and Hierarchical
Roughness.......................................... 142
7.5.3 HierarchicalRoughness............................... 145
7.5.4 ResultsandDiscussion ............................... 148
7.6 Summary ................................................. 151
8 Cassie–WenzelWettingRegimeTransition ........................ 153
8.1 TheCassie–WenzelTransitionandtheContactAngleHysteresis... 153