A Study of Mixed Aqueous Solutions of Hydrocarbon and

4 A Study of Mixed Aqueous Solutions of Hydrocarbon and Fluorocarbon Surfactants Using 8-Anilino-1-naphthalenesulfonic Acid Ammonium Salt

Downloaded by HARVARD UNIV on June 17, 2014 | http://pubs.acs.org Publication Date: June 5, 1986 | doi: 10.1021/bk-1986-0311.ch004

Kenjiro Μeguro, Yasushi Muto, Fujio Sakurai, and Kunio Esumi Department of Applied Chemistry and Institute of Colloid and Interface Science, Science University of Tokyo, Kagurazaka, Shinjuku-ku, Tokyo 162, Japan

The miscibility between hydrocarbon and fluorocarbon surfactants was studied by means of a steady-state fluorescence. Three mixed aqueous solutions of sur factants were employed; sodium dodecyl sulfate (SDS)-p[(CF ) CF] C=C(CF )O(CH CH O) -CH (NF), hexaoxyethylene3 2

2

3

2

2

7

3

glycol dodecyl ether (6ED)-lithium fluorooctane sulfonate (LiFOS), and 6ED-NF· The fluorescence probe was 8anilino-1-naphthalene sulfonic acid ammonium salt (ANS). Since ANS was not solubilized into fluorocarbon micelles, the existence of mixed micelles formed by the fluoro carbon and hydrocarbon surfactants can be discussed. (i) 6ED-LiFOS mixed system: When the concentra tion of 6ED was fixed, the fluorescence intensity of ANS decreased with increasing the concentration of LiFOS, indicating that mixed micelles are formed. (ii) 6ED-NF mixed system: The result was similar to that of (i). However, the mixed micelles are not formed at concentra tions below the CMC of NF. (iii) SDS-NF mixed system: When the concentration of NF was fixed and the concen tration of SDS was increased, the fluorescence intensity of ANS remained constant, suggesting that pure NF and pure SDS micelles are formed, Further, the above re sults are confirmed by conductivity measurements. Recently, some studies on the mixture of fluorocarbon and hydrocarbon materials have been carried out by surface tension, interfacial tension, differential conductance, NMR and solubilization methods(19). Mukerjee(5} and Funasaki(2) reported that fluorocarbon and hydrocarbon mixtures exhibit departure from ideal solution theory. Suzuku and Meguro et al. (V_,£) have been studying the interaction of fluorocarbon and hydrocarbon surfactants by the use of the ketoenol tautomerism of benzoylacetoanilide(BZAA) as a probe and they found the existence of a mixed micelle between lithium fluorooctane sulfonate(LiFOS) and hexaoxyethylene glycol dodecyl ether(6ED). As one of the probes, fluorescence compounds are known. The fluorescence probe such as 8-anilino-l-naphthalene sulfonic acid ammonium salt(ANS) has been used as an indicator of membrane 0097-6156/ 86/ 0311 -0061 $06.00/ 0 © 1986 American Chemical Society In Phenomena in Mixed Surfactant Systems; Scamehorn, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

62

P H E N O M E N A IN M I X E D S U R F A C T A N T S Y S T E M S

potential(10,11). elucidating since

the

nonpolar

the

Further,

properties

quantum y i e l d

hydrocarbon intensity

in

increases

is

this

larger

the

probe

aqueous

has for

fact, than

presence

because

been

useful

surfactant

fluorescence

From

surfactant

concentration(CMC) of

of

environment.

this

of

of

ANS i s

when

a

enhanced

in

concentration

its

critical

the

ANS p r o b e ,

ANS m o l e c u l e s

for

solutions(11-13),

adsorb

a

of

a

micelle

at

the

fluorescence

the

outerlayer

micelles. Further,

we

fluorocarbon

have

observed

surfactant

that

micelles,

ANS i s

so

the

fluorocarbon

and h y d r o c a r b o n s u r f a c t a n t s

fluorescence

probe, ANS.

not

solubilized

miscibility c a n be

of

into

the

studied

by u s i n g

the

Experimental


Materials.

Lithium

synthesized dodecyl

C^H

2

H76ED)

2

2

was

6ED was

measurements.

p u r i f i e d by

p-[(CF ) CF] C=C(CF 3

0(CH CH 0)

2

2

7

acid

from Nikko

pure

as

confirmed

was

c

sulfate,

from ethanol

3

sulfonic

was

glycol

donated

^ 2

H

S

2 5

° 3

was

and C h e m i c a l I n d u s t r y Company

supplied

through M i l l i - Q conductivity

by

D a i n i p p o n Ink

used

in

all

experiments

system(Nihon

fell

below

10

Perfluorocarbon

obtained

pp-2)

The water

Millipjre -il

was

Co.)

p u r i f i e d by until

a

by Neos C o .

ammonium s a l t ( A N S )

Ltd.

was

N

twice.

f r o m Wako P u r e C h e m i c a l I n d u s t r i e s , Ltd.

by

chromatography(TLC) and

Sodium d o d e c y l

)0(CH CH 0) CH (NF)

2

SO^LiiLiFOS)

obtained

highly

layer

recrystallization

8-Anilmo-l-naphthalene

C F

Hexaoxyetnylene

chromatography(GLC), t h i n

tension

was

sulfonate,

method{7).

Company L t d . , T o k y o .

gas-liquid surface

fluorooctane

a previous

ether,

Chemicals

(SDS)

by

its

oil(pp-l,

passing

specific

cm

Measurement The 25

fluorescence

C with

a

concentration spectra

of

nm,

and

The

and 500

surface

Wilhelmy

plate

The

The

and

Figure

intensity

CMC w a s

tension

the

the

the

The

fluorescence

nm i n w a t e r ,

and w i t h

was

was

done

at

377

emission 25

performed

at

Electronics

probe,

change

at

the

ANS i n

that

of of

ANS i n

the of

nm

at

in

520

nm,

C by

a

modified

25

C by

a

Ltd.).

the

aqueous

value

Since

below

with

6ED a n d

8.5x10

intensity of

ANS was

CMC.

coincided ANS i s

case

The s u r f a c t a n t the

the

single

the

of

into

CMC, the

inflection at

for

SDS).

hydrocarbon

was

about

ten-fold

larger

b o t h ANS a n d SDS a r e

anionic,

the

is

CMC, the

p r o b a b l y due

the

These

the

SDS m i c e l l e s

the

6ED a n d S D S (

the

the

fluorescence

above

6ED s o l u t i o n

in

p r o p o r t i o n a l to

the

CMC o f

ANS

hydrocarbon

concentration

mole/1

solubilized

Further,

Since ANS i n

In

the

constant

for

micelles.

fluorescence

intensity

above

CMC.

nearly

mole/1

in

solution.

ANS h a d a

point

solution.

solubility

360

at

The

ST-1).

fluorescence

fluorescence

indicate

intensity

measurement

measurement

concentration of

surfactant

mole/1. at

SDS m i c e l l e s

MODEL C M - 3 0 E T ( T O A

surfactant

6x10

findings

SDS

of

appeared

inflection

1x10

measured

650-10S).

respectively.

1 shows

surfactant,

point

s a m p l e .was

solution

aqueous

surfactant

each

Discussion

behavior

surfactant the

at

method(Shimadzu

meter

ANS i n

excitation

nm i n

conductivity

conductivity Results

nm,

fixed

with

370

of

spectrophotometer(Hitachi

ANS w a s

were measured

6ED m i c e l l e s , 435

spectrum

fluorescence

fluorescence

to

the

than

in

lower electric

In Phenomena in Mixed Surfactant Systems; Scamehorn, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

4.

repulsion aqueous the

b e t w e e n ANS a n d S D S .

solution,

system

addition surface

with

of in

due

band

of

wavelength

the

with of

and

emission

shifted almost

to

Above nm,

solution

it

at

Furthermore, excitation 500

nm,

their

above

the

other

CMC,

the

emission

wavelength

were

same

the

SDS

CMCs, a

maxima were

485

360

the

probe,ANS,

These

of

the

used

in

band

the

the

In water,

the

the

520

nm,

excitation

former

wavelengths

as

the

solvent.

aqueous

micelle

of

but

nm a n d

solution,

nm.

layer,

micelles.

shorter

concentration.

ethyleneglycol

layer

CMC o f

determined insoluble

as

by in

not

SDS a q u e o u s maxima a r e

of

surfactant

which would

solution, reached

The

behavior of

show

the

at

370

nm a n d

the

of

of

6ED-LÏFOS with

constant.

surfactant NF w a s

s u p p o r t i n g the

probe,

above the and

solutign

about

6x10

T h e s e CMCs

ANS w a s

found

results

showing

were

to

be that

surfactant. ANS i n

the

mixed

aqueous

a

were

fixed

It

the

above

gradually. the that

that

conductivity of

fixed

the

of

LiFOS its

of

ANS i n

with

ANS i s

6ED-LÎFOS

concentration.

CMC.

The

Here,

fluorescence

increasing less

of

6ED-LÏFOS

6ED f i x e d

corresponding to

The v a l u e s the

seems

concentrations

conductivity vs.

increasing

intensity

function of

the

soluble

in

the

micelle.

The b r e a k p o i n t

equivalent

as

LiFOS.

equivalent

From

remained

5 χ 1 θ "mole/1.

fluorocarbon

and

maximum e x c i t a t i o n

The C^C of

ANS p r o p o r t i o n a l l y d e c r e a s e d

concentration

apparent

also

and the

fluorescence

solutions

6ED c o n c e n t r a t i o n s

The

remained constant

measurements.

fluorescence

2 shows

aqueous

measured,

concentrations

fluorocarbon

about

o i l ,

into

s u r f a c t a n t ( N F and

at

solutions

Figure

intensity

was

tension

solubilized the

the

i n water.

LiFOS

even

wavelengths

intensity

fluorocarbon

is

fluorocarbon

intensity

ANS i n

those of

the

increased,

and e m i s s i o n

surface

ANS

surfactant

when

were

fluorescence

and t h a t

CMC.

the

fluorescence

the

mixed

to

wavelength

hand,

Further,

the

of this

outer

and e m i s s i o n

maximum e x c i t a t i o n

mixed

micelle

double

ethyleneglycol.

concentrations

mole/1

the

than

by

wavelength,

to

SDS

respectively.

On LiFOS)

their

longer

6ED a q u e o u s

latter

that

the

like

a

the

that

the

63

greater

maxima changed g r a d u a l l y and t h e

those

seems

exists

environment

CMC o f

at

ANS i n t o

ANS s h i f t e d

surfactant

and the

coincided with

suggests

electrical

above to

and e m i s s i o n

the

wavelength

377

Accordingly,

maxima o f

increasing

respectively.

the

solutions

ANS s h i f t e d

excitation

ANS w a s

electrical potential

s o l u b i l i z a t i o n of

emission

of

This

compression of

maxima o f

the

wavelengths


to

b o t h SDS a n d 6ED a q u e o u s

the

sodium c h l o r i d e to

intensity

added e l e c t r o l y t e .

increased

excitation

Adding

fluorescence

electrolyte

the

an

the

no

reduces

resulting In

Solutions of Hydrocarbon and Fluorocarbon Surfactants

MEGURO ET AL.

the

CMC i n

concentration of equivalent

mixed

below

LiFOS

solutions

and above

the

graph

was

the

of

disappeared

conductivity decreased

with

6ED c o n c e n t r a t i o n . of

the

fluorescence

mixed m i c e l l e s

measurement

are

formed i n

the

and c o n d u c t i v i t y i t 6ED-LÎF0S

mixed

of

the

is

system. Figure mixed

3 shows

aqueous

the

solutions

fixed


NF

the

6ED

at

inflection

concentration.

fluorescence as

intensity

function of

were

point In

a

was

above the

addition,

its

CMC.

same v a l u e the

ANS i n

NF-6ED

NF c o n c e n t r a t i o n .

The

The c o n c e n t r a t i o n regardless

concentrations

at

of

the

these


of fixed


64


F i g u r e 1.

Figure

2.

The r e l a t i o n s h i p between f l u o r e s c e n c e i n t e n s i t y v s . concentration of surfactant.

The r e l a t i o n s h i p between f l u o r e s c e n c e o f ANS and c o n c e n t r a t i o n o f LiFOS i n 6ED-LÎF0S mixed system. The f i x e d c o n c e n t r a t i o n s a r e ImM, 0.9mM, 0.8mM, 0.6mM and 0.4mM.


4.

inflection

points

fluorescence These the

suggest

that

NF, the

It

for

CMC t h e

6ED

system. 4 shows

mixed

were

means

even that

the

a

into

the

i t s CMC.

penetrate

other

the

that

hand,

into

above

6ED m i c e l l e s

NF m o l e c u l e s the

NF a n d 6ED i s

CMC o f

similar

intensity

function of

below

when t h e

do n o t

On t h e

below

fluorescence as

NF a n d below

65

the

as

system.

surfactant

fixed

the

NF.

results

of

are

not

NF, but to

the

ANS i n

its

and e m i s s i o n

concentration of

NF m o l e c u l e s

do n o t

intensity

ANS i n

CMC.

the

The

and

SDS-NF T h e SDS

fluorescence

wavelength

of

ANS w a s

NF i n c r e a s e d .

penetrate

above

LiFOS

NF c o n c e n t r a t i o n .

and above

a n d maximum e x c i t a t i o n

constant

result

the

CMC o f

constant

NF m o l e c u l e s

penetrate

above

solutions

concentrations kept

the

the

almost

CMC o f

6ED-LiF0S

hydrocarbon

aqueous

intensity

the

the

m i s c i b i l i t y of

Figure mixed

ANS was

NF m o l e c u l e s from

with

the

below

the

seems

miscible

coincided with

of

results

observed

almost

intensity

6ED m i c e l l e s

CMC o f



M E G U R O ET A L .

into

This

the

SDS

micelles. The

fluorescence

solutions

were

concentration

measured as was

intensities

of

the

the

case

of

ANS a t

mixed m i c e l l e s but,rather, Also, NF w a s The

fixed

several

fixed

conductivity the

mixed

be

case

were

at

CMC.

formed i n

of

several

Several This

the

a

the

NF c o n c e n t r a t i o n s , almost

can not

result

are

the

and the

same

at

the

Therefore,

it

is

penetrate

into

c o m p o n e n t N F a n d SDS m i c e l l e s

the

that that

in the

solution,

formed.

below

CMC o f

T h e NF

with

suggests

N F a n d SDS m i x e d

function of

concentrations

aqueous

fluorescence

N F a n d SDS m i x e d a q u e o u s

corresponding to

were

SDS-NF mixed

SDS c o n c e n t r a t i o n a g r e e d

measured as

solutions.

molecules

same

the

SDS c o n c e n t r a t i o n .

p u r e component m i c e l l e s

the

break point

its

SDS s o l u t i o n .

can not

conductivities

of

function of

above

the

single

that in

fixed

a

the

systems,

and above

the CMC.

SDS d i d n o t

values same

the

SDS c o n c e n t r a t i o n .

of

shift

in

equivalent

SDS c o n c e n t r a t i o n

concluded that

SDS m i c e l l e s ,

in

t h e NF

and t h a t

pure

exist.

Summary Three (ii)

mixed

6ED-NF In

and

surfactant (iii)

system

(i),

6ED a n d L i F O S

similar

to

such

6ED a n d S D S .

of

as

a mixed

systems

were

studied:

(i)

6ED-LÎF0S,

SDS-NF.

system

exhibit

consisting

of

Mixed m i c e l l e s

m i s c i b i l i t y behavior

two

are

hydrocarbon

formed over

surfactants,

a wide

range

concentrations. In

the

case

concentrations pure

CMC v a l u e s , On

over

of

below

the

the

formation

other

entire of

the

the

system the

(ii) ,

CMC o f

6ED a n d N F a r e both pure

mixed m i c e l l e s

hand,

in

system

(iii),

c o n c e n t r a t i o n range separate

are

not

miscible

surfactants;

above

at the

both

formed. SDS a n d N F a r e

studied,

resulting

immiscible in

the

micelles.



66


Figure

3.

The change 6ED-NF The

in

fluorescence

mixed system

fixed

as

a

intensity

of

ANS

in

f u n c t i o n of NF c o n c e n t r a t i o n .


are

ImM, 0 . 8 m M ,

0.6mM

and

0.4mM.

Figure

4.

The

change

in

fluorescence

mixed

system

as

a

fixed


intensity

of

ANS i n S D S - N F

f u n c t i o n o f NF c o n c e n t r a t i o n . are

25mM,

15mM

f

The

lOmM a n d 5mM.


4.

M EG U RO ET A L.


Acknowledgment The

authors

wish

to

thank

Neos

Co.

for

supplying

valuable


samples.

Literature Cited 1. Mukerjee, P. and Handa, T., J. Phys. Chem., 1981, 85, 2298. 2. Funasaki, N. and Hada, S., Chem. Letters, 1979, 717. 3. Mukerjee, P., JAOCS, 1982, 59, 573. 4. Funasaki, Ν. and Hada, S., J. Phys. Chem., 1983, 87, 342. 5. Mukerjee, P. and Yang, A.Y.S., ibid., 1976, 80, 1388. 6. Carlfors, J. and Stilbs, P., ibid., 1984, 88, 4410. 7. Meguro, Κ., Ueno, Μ., and Suzuki, T., Yukagaku, 1982, 31, 909. 8. Suzuki, T., Esumi, Κ., and Meguro, K., J. Colloid Interface Sci., 1983, 93, 205. 9. Funasaki, Ν., Hada, S., and Neya, S., Bull. Chem. Soc. Jpn., 1983, 56, 3839. 10. Haynes, D.H., and Staerk, H., J. Membrane Biol., 1974, 17, 313. 11. Haynes, D.H., ibid., 1974, 17, 341. 12. Birdi, K.S., Krag, T., and Klausen, J., J. Colloid Interface Sci., 1977, 62, 562. 13. Thomas, J.K., Chemical Review, 1980, 80, 283. 14. Lianos, P., and Zana, R., J. Colloid Interface Sci., 1981, 84, 100. RECEIVED

February 3, 1986


A Study of Mixed Aqueous Solutions of Hydrocarbon and

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