AKYPO®

Optimizing Coacervate Formation

1Synergistic effects of high molecular weight polyethylene oxide (PEO) and cationic cellulosic polymers on conditioning properties of hair and

skin care products. Wing Li, Susan L.P. Jordan, et.al. Cosmetics & Toiletries manufacture World wide. 31-35. 2004.

2A Brief Review of Polymer/Surfactant Interaction. Robert Y. Lochhead and Lisa R. Huisinga. The Institute for Formulation Science, The

University of Southern Mississippi, Hattiesburg, Mississippi USA. Cosmetics & Toiletries. Vol. 119, No. 2/February 2004.

3Formulating Conditioning Shampoos. Robert Y. Lochhead. The University of Southern Mississippi, Hattiesburg, MS, USA. Cosmetics &

Toiletries. Vol 116, No. 11/November 2001.

What is a COACERVATE?

A coacervate is a thermodynamically stable

aggregate of colloidal droplets held together by

electrostatic attractive forces that measures

few tens of microns. This aggregate is formed

by a polymer-surfactant complex which

separates from the solution as it is diluted1.

What is COACERVATION?

Coacervation is a physicochemical mechanism

that occurs while a composition based on a

cationic polymer and surfactant base is diluted.

Figure 1 illustrates this phenomenon.

Cationic polymers are compatible with anionic

surfactant systems, where they are soluble in

the final product (i.e. shampoo) because the

polymer and the air-water interface become

“saturated” with surfactant and normal

micelles first appear2,3. During the washing

step the surfactant concentration falls below

the critical level required for solubilisation

(CMC), and insoluble polymer/surfactant

complex, called coacervate, is formed. Figure 1

depicts the normal surface tension curve in

presence of a cationic polymer that shows two

breakpoints, *cac (critical aggregation

concentration), which represents the minimum

and maximum surfactant concentration at

which coacervate formation occurs. Finally, in

the rinsing step coacervate separates from the

Figure 1. Mechanism of coacervate formation.

++ +

+

Micelle

Cationic polymer

++ +

+

++ +

+

Micelle

Cationic polymer

Shampoo Concentration

Surface Tension (mN/m

)

Coacervation

Coacervate

Solubilization

*cac

Surfactant＋C-Polymer

Deposition

Surfactant DecreaseLeads to Aggregation

cmc

*cacRINSING

WASHING

Shampoo Concentration

Surface Tension (mN/m

)

Coacervation

Coacervate

Solubilization

*cac

Surfactant＋C-Polymer

Deposition

Surfactant DecreaseLeads to Aggregation

cmc

*cac

Shampoo Concentration

Surface Tension (mN/m

)

Coacervation

Coacervate

Solubilization

*cac

Surfactant＋C-Polymer

Deposition

Surfactant DecreaseLeads to Aggregation

cmc

*cacRINSING

WASHING

4 Polyquartenium-74: An Advanced Hair Conditioning Polymer. Eric Leroy. Rhodia Research, Aubervilliers, France. Cosmetics & Toiletries.

Vol. L123, LNo. L3/March L2008L

bulk solution and deposits on the hair or the

skin. Once deposited, cationic polymer

provides soft feel, conditioning effect, easy to

comb and pleasing in appearance. In addition,

coacervate aids in the deposition of insoluble

actives, such as silicone.

Many factors can modify the nature of the

coacervate:

• Polymer molecular weight & charge

density distribution

• Chemical surfactant structure

• Type and ratio of surfactant used

• Presence of electrolyte, pH, etc.

The amount of polymer deposition can be

controlled by selecting the appropriate grade of

polymer or by changing the surfactant used in

the system.

Fine Deposition Control using AKYPO®

Alkyl Ether Carboxylates are represented by

the following structure:

R-O-(CH2CH2O)n-CH2COOM

R is derived from fatty alcohols and is

generally between C4H9 and C18H37. EO-degree

is represented by n and can be between 2 and

20. M may be hydrogen or a cation such as

sodium, ammonium, magnesium or calcium.

AKYPO® forms a water soluble ring complex

with a cation which can be easily exchanged by

other inorganic as well organic cations. The

carboxyl group enables Alkyl Ether Carboxylic

acids to perform a double function as non-ionic

and anionic surfactant. Figure 2 shows the

water soluble ring complex formation and the

complexation with a cationic polymer. Because

of this structure, AKYPO® enhances coacervate

formation. Therefore, a higher level of polymer

deposition or insoluble actives on hair and skin

occurs.

+++

Figure 2. Water soluble ring complex formation

and complexation with a cationic polymer.

How is Coacervate Formation Measured?

The most common way to determine the

coacervate formation is by transmittance

measurement with a UV spectrophotometer at

600nm4, for different dilution ratios of test

composition. Figure 3 depicts the coacervation

behaviour of different systems with

polyquartenium-10 (PQ-10).

Test composition at 12% total active matter, 0.3%

polymer and pH 6.5:

a) SLES-2EO/CAPB at 3:1 ratio

Table I: Alkyl Ether Carboxylic acids and derivatives for Personal Care applications

INCI Name Alkyl Chain

n M Appearance (20ºC)

Active Matter (%)

Trademark

Laureth-6 Carboxylic Acid C12-14 4.5 H Liquid ≈ 92 AKYPO RLM 45 CA

Sodium Laureth-6 Carboxylate C12-14 4.5 Na Paste ≈ 82 AKYPO RLM 45 N

Sodium Laureth-6 Carboxylate C12-14 4.5 Na Liquid ≈ 22 AKYPO SOFT 45 HP

Sodium Laureth-5 Carboxylate C12 4 Na Paste ≈ 60 AKYPO FOAM RL 40

Laureth-11 Carboxylic Acid C12-14 10 H Liquid ≈ 90 AKYPO RLM 100

Sodium Laureth-11 Carboxylate C12-14 10 Na Liquid ≈ 70 AKYPO SOFT 100 BVC

5 LCationic Lcellulosic Lpolymers Lwith Lmultifunctional Land Loustanding Lperformance L for Lpersonal Lcare. LWing L i, LSusan L .P. LJordan. LAmenchol

Corporation, Cosmetics & Toiletries manufacture World wide. 157 – 160. 2003.

b) AKYPO® RLM 45CA/CAPB at 3:1 ratio

c) SLES-2EO/AKYPO® RLM 45CA/CAPB at 2:1:1 ratio

Abbreviations:

SLES-2EO: Sodium Laureth Sulfate

CAPB: Cocamidopropyl Betaine

50

60

70

80

90

100

1 10 100 1000

Dilution ratio

Transmittance (%

)

a) none b) main surfac tantc ) c o- surf actant

Figure 3. Coacervation profiles of PQ-10 with

AKYPO®

Haze region is linked to the quantity of

coacervates. Test compositions with AKYPO®

show higher haze region. Therefore, AKYPO®

enhances coacervate formation providing

better conditioning effect.

The minimum of transmission for the test

composition based on AKYPO® as main

surfactant (figure 3) is obtained at low dilution

ratio, which is a sign that more substantivity

will be achieved. Therefore, better combability

and conditioning effect is expected. On the

other hand, test composition based on AKYPO®

as co-surfactant shows the minimum of

transmission at a high dilution ratio, which

provides a soft feel and volume enhancement

of the hair5.

Coacervation Benefits…

� Excellent Combability

AKYPO® shows a significant combing force

reduction. Figure 4 illustrates the combing

force of two test compositions with 0.3% of

polymer. The percentage reduction of

combing force versus composition without

AKYPO® for polyquartenium-10 and

polyquartenium-7 are 21% and 17%.

765

424

603

353

0

200

400

600

800

1000

PQ-10 PQ-7Wet Combability Force, gf

SLES-2EO/CAPB at 3:1 ratio

AKYPO RLM 45CA/CAPB at 3:1 ratio

Figure 4. Combing force profile

� Cost/Performance Balance

AKYPO® improves combing force independently

of % polymer but achieving lower value at

0.3% polymer. Using AKYPO®, polymer

concentration can be reduced maintaining the

performance and optimizing the cost, as it can

be seen in Figure 5.

723

524

779

541560

422

0

200

400

600

800

1000

SLES-2EO/CAPB SLES-2EO/AKYPO RLM

45CA/CAPB

Wet Combability Force, gf 0.05% PQ-10

0.10% PQ-10

0.30% PQ-10

Figure 5. Combing Force profile at different %

of PQ-10

� Superior Polymer deposition

AKYPO deposits significantly more polymer and,

additionally, when silicone is added, better

assistance deposition is obtained. Figure 6

illustrates polymer deposition which is

measured indirectly by detecting the amount of

anionic Red 80 dye bounded by the cationic

polymer deposition on wool.

Higher ∆E value means superior polymer

deposition.

6.4

16.718.5

24.7

0

10

20

30

40

without silicone 0,5% silicone

∆∆ ∆∆E

(C

IE L

*a*b

*)

SLES-2EO/CAPB + 0,3%PQ-10

SLES-2EO/AKYPO RLM 45CA/CAPB + 0,3%PQ-10

Figure 6. Polymer deposition profile

� Hair Conditioning without Build-Up

If too much polymer is deposited onto the hair

surface, polymer build-up can occur after many

shampoo treatments. It will cause the hair to

be weighted down and appear limp, resulting

in a loss of volume. Composition with AKYPO®

does not build-up after several applications; on

the contrary it increases the volumizing ability,

as seen in Figure 7 and 8.

6.48.8

18.5 18.7

0

10

20

30

40

1 wash 3 washes

∆∆ ∆∆E

(C

IE L

*a*b

*)

SLES-2EO/CAPB + 0.3% PQ-10

SLES-2EO/AKYPO RLM 45CA/CAPB + 0.3% PQ-10

Figure 7. Build-up of PQ-10 with AKYPO®

5.3

6.3

0

1

2

3

4

5

6

7

SLES-2EO/CAPB +

0.3%PQ-10

SLES-2EO/AKYPO RLM

45CA/CAPB +

0.3%PQ-10

Avg. Tress Diameter (cm)

Figure 8. Volume measurement of PQ-10 with

AKYPO®

� Sensorial Benefits

Sensorial consumer benefits have been

demonstrated with a basic shampoo

formulation and on a final shower cream

formula (C-141).

1

2

3

4

5Foam performance

Wet Smoothness

Rinse-off

Smoothness during rinse-off

Detangling

Wet Combability

Dry Combability

Dry Feel

Loose hair

Shine

SLES/CAPB at 3:1 ratio, 0.3% PQ-10

SLES/AKYPO RLM 45CA/CAPB at 2:1:1 ratio, 0.3% PQ-10

����

����

����

Scores: 1 = very bad; 5 = very good.

� Significant differences.

Figure 9.Sensorial test profile of basic shampoo

formula

AKYPO® range, a new approach to coacervation technology

1

2

3

4

5

Foam speed

Foam volume

Foam size

Foam creaminess

Wet Smoothness Rinse-off

Smoothness during

rinse-off

Dry Smoothness

Moisturising

Market product AKYPO

�

�

��

Scores: 1 = very bad; 5 = very good.

� Significant differences.

Figure 10. Sensorial test profile of a final

shower cream (C-141).

Formulations with AKYPO® offer truly

noticeable consumer benefits. AKYPO® in a

basic shampoo formula provides excellent wet

hair detangling & combing and imparts

smoothness during rinse-off. In addition

AKYPO® offers creamy foam and a rinses out

well, with a soft skin feel in shower gel cream

products with high oil content.

Contact Kao Chemicals Europe

For more information, complete literature, and

product samples, you can reach a Kao

Chemicals Europe representative at the

following numbers or visit our web site at

www.kaochemicals-eu.com:

Kao Corporation, S.A.

Puig dels Tudons, 10

E-08210 Barberà del Vall

Tel: +34 93 7399-300

Fax: +34 93 7399-377

e-mail: sales@kao.es

Kao Chemicals GmbH

Kupferstrasse 1

D-46446 Emmerich, Germany

Tel: +49(0)2822 711-0

Fax: +49(0)2822 711-201

e-mail: sales@kaochemicals.de

The capacity of AKYPO® surfactants to promote coacervate formation allows

optimizing polymers performance with the best cost/effectiveness ratio.