surface energy of various liquids

7/27/2019 Surface Energy of Various Liquids

http://slidepdf.com/reader/full/surface-energy-of-various-liquids 1/15

Mallikarjunachari.G Date: 15/02/2013 1/3

Work of Adhesion

Where , Surface energy per unit area of surface 1 and 2

1

1

= 2

1

3

=

1

2

1

2

2

1

12

1

12

= 2

4

1

23

3 1

23

3 = 33 3 3

Definition: The work of adhesion is the separation to create two new surfaces from one interface

or The free energy change, or reversible work done, to separate unit areas of two media 1 and 2 from

contact to infinite in vacuum. Jacob.N. Israelachvili

Ceramic Polymer Interface Development

Objective of Research Research MethodologyCourse Work

DetailsMaterial Description and

Technique used




Adsorption Effect

= = v v

differs from v

by the “spreading pressure” which represents the lowering of the surface energy of material in vacuum by adsorption of the vapour

1= - v




Technique used




Neumann Van Oss – Chaudhury -Good OWRK

+ −

(mJ/m2)

Diiodomethane 50.8 50.8 0.0 0.0 50.8 0.0

Ethylene Glycol 48.0 29.0 1.9 47.0 29.0 19.0

Formamide 58.0 39.0 2.3 39.6 39.0 19.0

Water 72.8 21.8 25.5 25.5 21.8 51.0

Surface tensions of various solvents

Ref: Thesis




Technique used




The work of adhesion &

practical adhesion

G = W A x

G = Fracture Energy W A = Work of adhesion = temperature and

rate dependent viscoelastic term

Fowkes’ Theory:

Assumptions:

Additivity

= . . . d = dispersion forcep = polar forceh = hydrogen bonding forcei = induction force(Debye)ab= acid/base force

Dispersion

Geometric Mean

= 2

= 2

Polar…

The work of adhesion

= 1 = . . .




Technique used



Mallikar unachari.G Date: 15 02 2013 1 3

Method of OW (Owens-Wendt)

. . = 0.5(1cos

. . = 0.5(1cos =

Where = surface free energy of solid

= Dispersion component

= Polar component

Method of vOCG (van Oss-Chaudhury-Good)

Solid surface free energy

Dispersion

(London dispersion Van der Waals)

Polar

(Polar + hydrogen +Inductive + Acid Base)

Solid surface free energy

Van der Waals

Dipole –dipole, dipole –induced dipole and London

Acid Base

. +− . −+ . = 0.5 1

.

+

− .

−

+ .

= 0.5 1

. +− . −+ . = 0.5 1

= 2 +− .

=

+, − =Acid , Base interactions




Technique used

Liquid Contact Angles required

2 3







Technique used

Volume(microliters) Drop radius(mm) Contact Angle(0)

1 1.0 54.3

3 1.5 54.5

5 1.75 53.9

10 2.3 53.8




Hysteresis

1. Mechanical Hysteresis surface roughness

2. Chemical Hysteresis

Parameters affect the contact angle

1. Temperature

2. Material TransitionsEg: glass and crystalline transitions,

contaminants and adsorbed materials polar and apolar interactions,drop dimension,surface crystallinity,molecular weight and conformation of chains.




Technique used




Substrate Diiodomethane Distilled Water Glycerol

Glass 34.7( ±2.2) 49.5( ±3.1) 48.5( ±3.5)

Epoxy 26.6( ±1.8) 70.6( ±3.9) 62.5( ±2.6)

Contact Angle Measurements (degrees)

Surface Energies of Glass and Epoxy (mJ/m2 )

Substrate + −

Glass 42.2 0.43 27.4 6.9 49.1

Epoxy 45.6 0.02 10.39 0.9 46.5

Silica 78.0 - - 209.0 287.0

Epoxy 41.2 - - 5.0 46.2




Technique used




Surface Force Apparatus




Technique used




Sources of Thermodynamic Contact Angle Hysteresis

General

Assumption

Specific

AssumptionEffect on Hysteresis

Time

Dependent

Surface I smoothSurface must be smooth at

the 0.1 to 0.5 μm level

∆θ increase with increasing roughness( θadv. increases and θ rec decreases with

increasing roughness)No

Surface ishomogeneous

Surface must behomogeneous at the 0.1

μm level and above

θadv. dependent on low energy phase:θ rec dependent on high energy phase

No




Technique used




Sources of Kinetic Contact Angle Hysteresis

General Assumption

Specific Assumption Effect on Hysteresis Time Dependent

Surface is nondeformableModulus of elasticity in

surface > 3x105dyne/cm

Not known Yes due to surface

deformation/relaxationeffects

Wetting liquid does

not penetratesurface

Liquid molecular

volume > 60-70 cc-mole

Increased liquid penetrationlends to increased hysteresis

Yes due manly to

diffusion

Surface does notreorient

Reorientation time attime of measurement

Increased tendency to orientlends to increased hysteresis

Yes

Surface immobile,therefore, surface

entropy is constant

Configurationalentropy independentof local environment

Unknown but probably increase in hysteresis as

surface mobility increases Yes




Technique used


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Literature




Technique used

EFFECTS OF STOICHIOMETRY AND EPOXY MOLECULAR MASS ON WETTABILITY AND INTERFACIALMICROSTRUCTURES OF AMINE-CURED EPOXIES

Epoxy Equiv.Mass (g/mol)

degree degree

Surface free energy components

(mJ/m2)

190 63.1±0.7 40.6±1.3 36.88 16.97 53.85

255 59.3±1.6 32.1±4.2 40.40 18.05 58.45

500 65.7±1.4 41.9±1.8 36.32 15.80 52.13

900 58.5±1.5 44.1±1.3 35.28 19.74 55.03

2250 61.7±1.9 44.1±1.1 35.30 18.08 53.39

3050 62.3±1.6 44.4±1.2 35.17 17.81 52.98

, water and methylene iodine contact angle respectively, , , : Nonpolar, polar and total surface free energy,

respectively. Values after the ± sign indicate one standard deviation.

Conclusion: Epoxy molecular mass does not seem to affect wettability of amine – cured epoxies

i l f l



Literature: The contact angle of thin-uncured epoxy films: thickness effect




Technique used

Liquid Time (min)

1 5 10 15 20 25

MI 43.1 40.5 32.8 30.4 26.8 25.4

EG 46.1 46.7 45 47.1 45.2 46.9

Contact Angle of EG and and MI on a thin film

Adhesion and debonding of multi-layer thin ®lmstructures

C i P l I f D l



Interface Delamination




Technique used

Critical Energy Release Rate: (Gc)

1. Physical Interaction:

4. Heat Dissipation:ℎ 3. Mechanical Interaction:

2. Chemical Bongs:

Irreversible material deformation

Gc = ( + )(1+ ) +

C i P l I t f D l t



Thermodynamic Work of Adhesion




Technique used

(1 cos) = 2( +− −+ )

∗ = ( +− −+

= ∗ ∗ 2 ( +− −+

= ( +− −+

surface energy of various liquids

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