Theory

Instrumentation

Applications

Theory

Instrumentation

Applications

SurPASS Electrokinetic AnalyzerZeta Potential Measurement for Solid Samples

SurPASS Electrokinetic AnalyzerZeta Potential Measurement for Solid Samples

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Surface and Interface Analysis

Spectroscopy Secondary Ion Mass Spectrometry X-ray Photoelectron Spectroscopy Energy Dispersive X-ray fluorescence Raman spectroscopy Ion Scattering Spectroscopy IR, UV/VIS spectroscopy

Microscopy Scanning Electron Microscopy Transmission Electron Microscopy Atomic Force Microscopy Confocal Laser Scanning Microscopy Light microscopy

Interface analysis Contact angle (static, dynamic) Surface tension Streaming potential Surface spectroscopy Gas adsorption

Analysis of …

… chemical composition of surface

… surface topography

… morphology of interfaces

… surface energy and (de-)wetting

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Streaming Potential Method

Liquid phase (electrolyte solution) pumped through the measuring cell (containing sample)

pressure difference

relative movement of the charges in the electrochemical double layer

detection of streaming potential U = U(p)

electrodeelectrode

sampleflowingliquid

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- - - - - - - - - - -

+ + + + + + + +Electrochemical double layer at equilibrium

- - - - - - - - - - -

++ + + + + + + +

Fluid Flow

Electrolyte flow forced across solid surface

- - - - - - - - - - -

++

++ ++ + +

Fluid Flow

Ion accumulation causes potential difference

- - - - - - - - - - -

++

++ ++ + +

Backflow Current

Potential difference causes backflow current

Mechanism of Streaming Potential

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SurPASS Measurement Set-Up

RS 232

VisioLab for SurPASS

SurPASS Electrokinetic Analyzer

ConductivitypH

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Cylindrical Cell

Natural and technical fibres Hair Textile fibres and fabrics Powder samples with > 25 µm size Particle and granular samples

electrolyteinlet/outlet

electrolyteinlet/outlet

perforateddisc

sample

electrode

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Clamping Cell

25 5 mm2

electrolyteinlet/outlet

spacersample

Flat membranes Foils Polymer sheets Rigid samples of different thickness

and shape with a flat surface

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Pressure Ramp Measurement

Electrolyte flow from left right

Measurement of streaming potential at various differential pressure

Reversal of flow direction

Linear regression for evaluation of “pressure ramp” slope

= dU

dp

0

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SurPASS Applications in . . .

Polymer industry

Synthetic fibre and textile industry

Processing of non-metallic, inorganic materials

Mining industry

Printing industry

Membrane and filtration technology

Biomaterials

Semiconductor industry

Paint and varnish industry

Cosmetics industry

etc.

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Textile purification

Fibre swelling

Hydrophobicity

Particle retention

Glass fibre finishing

Characterization of sizing agents

Surfactant interaction

etc.

Textile and Technical Fibres

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Solution with SurPASSTime resolved measurement of treated polyester fibres in Cylindrical Cell

Characterization of Polyester Fibre Preparation

SurfactantZeta potential (mV)

T = 0 min T = 15 min T = 60 min

untreated -35.10 -34.93

anionic-55.49 -57.49

-48.68 -51.75 -48.36

cationic

-22.22 -28.22 -32.24

-24.92 -29.41

-18.32 -18.15 -16.8

-13.17 -16.11

non-ionic -37.32 -36.87

Field of ApplicationTreatment of synthetic fibres with surface-active compounds after spinning to assure textile processing

ChallengeCharacterization of these surface-active compounds to forecast textile processibility of fibres

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0

100 150 200 250 300

Adhesive Length (10-6 N/tex)

Zet

a P

oten

tial (

mV

)

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Glass Fibre Finishing

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0

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60

2 3 4 5 6 7 8 9 10 11

pH (in 10-3 M KCl)

Zet

a P

ote

ntia

l (m

V)

untreated

sized

AMEO

0

20

40

60

80

100

120

140

15 25 35 45 55 65 75

lv (mJ/m2)

K

lv c

os

sv = 49.6 mJ/m2

sv = 47.8 mJ/m2

Electrokinetic measurement shows higher sensitivity to changes in surface chemistry of glass fibres than contact angle measurement

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Un

trea

ted

Sh

ampo

o

Rin

se

Co

ndi

tion

er

Rin

se

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0

10

20

30

Ze

ta P

ote

ntia

l (m

V)

Zeta Potential of Human Hair

Source: E.D.Goddard, P.S.Leung, Sonderdruck aus Parfümerie und Kosmetik 68 (1987)

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Surface modification

Lacquer adhesion

Composite materials

Hydrophobic vs. hydrophilic behaviour

Protein adsorption in biomaterials engineering

Wetting and de-wetting behaviour

etc.

Polymer Characterization

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Hydrophilisation of Polyolefines

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2 3 4 5 6 7 8 9 10 11

pH

Zet

a P

oten

tial (

mV

)

untreated 1 min

2 min 3 min

4 min 5 min

0

20

40

60

80

100

0 1 2 3 4 5Treatment Time (min)

Con

tact

Ang

le (

°)

Aim Modification of the polymer surface

properties with retention of the bulk behaviour

Example

Introduction of acidic surface groups

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Plastics for Medical Application

Field of ApplicationMembrane material for haemodialysis

ChallengeCompatibility of membrane material with human organism

Solution with SurPASSZeta potential determination of capillary membranes in Cylindrical Cell and flat membranes in Clamping Cell

Examination of plastics surface in natural aqueous environment

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0

5

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2 3 4 5 6 7 8 9 10 11pH

Zet

a P

oten

tial (

mV

)

untreat w/o hep

amine-mod w/o hep

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0

5

10

2 3 4 5 6 7 8 9 10 11pH

Zet

a P

oten

tial (

mV

)

untreat w/ hep

amine-mod w/ hep

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Metal Oxide and Semiconductor Processes

Photoresist coating

Silicon wafer cleaning

Metal layer characterization

Chemical Mechanical Polishing

Particle adhesion

etc.

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0

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3 4 5 6 7 8 9 10 11

pH

Zet

a P

oten

tial (

mV

)

alkaline pickled/boiled

alkaline pickled

alkaline/acid pickled

Electrokinetic Measurement of Aluminium Sheets

Treatment Alkaline pickled with NaOH and Na2CO3

and boiled in H20 for 10 min

Alkaline pickled only Alkaline and then acid pickled with H2SO4

and H2O2

Results Alkaline pickling and boiling introduces

only few dissociable surface groups with no plateau in zeta potential and IEP in the neutral range Procedure produces AlOOH

(Böhmit) on Al(OH)3 (Bayerit) layer

More dissociable surface groups without boiling plateau in zeta potential at low pH IEP shifted towards higher pHSource: C. Bellmann et al, Fresenius J Anal Chem 358 (1997) 255

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pH

Zet

a P

oten

tial (

mV

)

alkaline pickled/boiled

alkaline pickled

alkaline/acid pickled

Electrokinetic Measurement of Aluminium Sheets

Treatment Alkaline pickled with NaOH and Na2CO3

and boiled in H20 for 10 min

Alkaline pickled only Alkaline and then acid pickled with H2SO4

and H2O2

Application of organic oligomer material with acidic functional groups

Results IEP changes to lower pH Ion adsorption processes dominate Oligomer removed for alkaline/acid

pickled Al surface at pH > 7

Source: C. Bellmann et al, Fresenius J Anal Chem 358 (1997) 255

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0

200

400

600

800

1000

1200

2 3 4 5 6 7 8 9 10

pH

Pa

rtic

le n

o.

on

wa

fer

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0

10

Ze

ta P

ote

ntia

l (mV

)

Conc. of PSL

Piranha

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20

3 4 5 6 7 8 9 10pH

Zet

a P

oten

tial (

mV

)

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Zet

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mV

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Piranha

Piranha + BOE

Piranha, BOE + H3PO4

RCA 1

Particle Deposition on Si3N4 Wafer

Sample TreatmentRatio

IEPSi/N Si/O N/O

Piranha 0.77 2.99 3.88 3.7

Piranha + BOE 0.81 3.78 4.66 5.3

Piranha, BOE + H3PO4 0.80 2.53 3.16 3.5

Zeta potential depends on cleaning treatment of LPCVD Si3N4 wafers

Correlation between N/O ratio (XPS data) and IEP

Contamination of wafer surface with Polystyrene particles follows the zeta potential

Source: D.Jan, S.Raghavan, Proc. 3rd Int. Symp. on Cleaning Technology in Semiconductor Device Manufacturing (1993)

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CMP Slurry / Cu Surface Interaction

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0

5

10

15

20

25

30

1E-07 1E-06 1E-05 1E-04 1E-03 1E-02surfactant concentration in 10-4 M KCl (mol/l)

Zet

a P

oten

tial (

mV

)

cationic

non-ionic

anionic

cationic dodecyl trimethyl ammounium bromide

non-ionic Marlipal O13/100 (C13-alcohol polyethylene glycol ether)

anionic sodium dodecyl sulphate

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Partial List of EKA Customers