Physicochemical Properties of Surfactants A. M. MANKOWICH Paint and Chemical Laboratory, Aberdeen Proving Ground, Md.
a
cs
.
PREVIOUS paper (16) proposed a scientific method for selection of surface active agents for specific detergent applications, based on the determination of the numerical criteria of the fundamental factors of the detergencyprocessand thecofactors for soil removal. Two of the physicochemical factors of the process were studied, suspending power and micellar solubilization. This paper is concerned with the determination of the numerical criteria of a group of factors consisting of surface tension, interfacial tension, contact angle, spreading coefficient, adhesion tension, and work of adhesion. These properties were found not t o meet the requirements of fundamental factors as previously defined (16). For this reason, no predictions for detergent applications are possible from the data obtained. Even factors meeting these requirements can be significant for a given application only to the extent t o which the cofactors for the soils and surfaces concerned show these to be of consequence. The fact that negative results were obtained from this viewpoint indicates either t h a t these factors are not prime or that one or more uncontrolled variables has been operative in the test methods. This possibility is under investigation a t the present time, and will be reported on in the future. Because many workers in the field are concerned with the desired final numerical properties of preparations they manufacture incorporating surfactants, and because these workers will be aided by hitherto unavailable quantitative knowledge of the properties of many types and subtypes of surfactants, it is believed that the physicochemical data obtained in the course of the over-all program will be of interest. The parallelism between low surface and interfacial tensions and ease of emulsification has been noted (6, 14). This correlation is significant because emulsification has been said to be one of the chief actions in the mechanism of detergency (18,1.9). The other factors reported here are related t o the property of wetting, which has been considered by some investigators the principal action of the detergency process (3, 19, 80). Surface tension results from the unbalanced molecular forces a t a liquid-air interface. Depression of the surface tension of water by surface active materials is due t o concentration of the latter molecules in the surface layer (positive adsorption). The substitution of surfactant (surface active) molecules for some water molecules in the surface layer reduces the net molecular forces a t the surface. Interfacial tension is the tension at a liquid-liquid interface. T h e greater the mutual solubility of two pure liquids, the lower the interfacial tension; at complete soluhility, the latter becomes zero. Reduction of the interfacial tension between two insoluble liquids is accomplished by solution of a surfactant in one of the liquids. The surfactant forms an interface at least three molecules thick between the two phasesoil and water, for example-consisting in the most simple case of a layer of surfactant molecules with hydrophilic heads adjacent to a layer of water molecules and hydrophobic tails adjacent t o a layer of oil molecules (6). According t o one theory, emulsification occurs because the interfacial film, seeking a condition of minimum free surface energy, curls toward the side (water-surfactant or oil-surfactant) with the higher surface tension (7, 8). Many indexes for wetting have been proposed, including the physicochemical factors of contact angle, cosine contact angle, spreading coefficient, adhesion tension, and work of adhesion, as well as surface and interfacial tensions. A considerable degree
of interdependency exists among these factors, most of which are of limited significance because of derivation or definition. Wetting is the action occurring on the contact of solid and liquid phases t o form a solid-liquid interface. A tangent t o the free liquid surface from any point of the solid-liquid-air interface makes an angle with the solid surface t h a t is the contact angle-measured through the liquid by convention. Assuming the following nomenclature, it has been shown (8) that a t equilibrium if
e
=
contact angle
S L = surface tension of li uid SS = surface tension of so id S S L = interfacial tension, solid-liquid
4
then,
sS = sSL+ sLCOS e
(1)
Equation 1 indicates the relationship between wetting as measured by the contact angle and the solid, liquid, and solid-liquid tensions. Actually, three types of wetting are possible, adhesional, spreading, and immersional (17). I n adhesional wetting, a solidair and liquid-air interface are brought together to form a solidliquid interface. The free surface energy change of the process, or equivalent solid-liquid work of adhesion, WsL-work necessary t o restore original conditions-is WSL =
ss
+ SL -
SSL
Substituting Equation 1 in the above gives
wSL= sL+ sLCOS e
(2)
Work of adhesion is thus an index of adhesional wetting and is dependent on the values of the solid, liquid, and solid-liquid tensions, and the contact angle. Work of adhesion values have been used to estimate preferential wetting when comparing a surfact a n t solution and a liquid soil. In spreading wetting, a solid-air interface is replaced with liquid-air and solid-liquid interfaces. The free surface energy change, or work of spreading, W S P is , W S P
=
s s - SL
- SSL
(3)
Substitution of Equation 1 in Equation 3 gives
wsp= sLCOS e - sL
(4)
Again, as in the expression for work of adhesion, the solid tensions are eliminated, and spreading wetting (Wsp) may be estimated from values of the liquid surface tension and contact angle. The factor of spreading coefficient is actually a special cme of Equation 3, in which readily determined liquid-air and liquidliquid tensions are used t o compute the extent of the spreading of one liquid on another (10, 18). I n immersional wetting, a solidair interface is replaced by a solid-liquid interface. Assuming that the bulk surface energy is the same as the surface energy of the first molecular layer, the free surface energy change, or work of immersion, W I Mis,
W I M= Ss
- SSL
From Equation 1, it is seen that
Ss Hence,
2751 9
- SSL
=
SL cos e
W I M= SLCOS 6
(5)
INDUSTRIAL AND ENGINEERING CHEMISTRY
2160
SURFACE TENSION, DYNES/CM.
Figure 1. Contact Angle Versus Surface Tension of Selected Detergents in 0.4yo Concentration 0 Aqueous solution
+
0.1 % sodium sulfate
Voi. 45, No. 12
It has been found that the limiting size is 1.2 mm. (f6), and that drops with a larger diameter form varying angles of contact on the same surface, while smallcr drops assume the constant value of the advancing contact angle. Drops of the proper size require the use of a microsyringe or very fine capillary glass tubing, both of which procedures are slow and laborious. Larger drops will form reproducible equilibrium contact angks provided their support is tapped or caused to vibrate (9). 'The larger. more readily produced drops (2.0 t o 2.5 mm. in diameter) can also be compensated for gravitational effect by applying a coriection factor derived by Mack (16). In using the modified drop dimension method, cleaned microslides, 7 5 by 25 mm., were coated on one side with molten paraffin wax, using a glass stirring rod for uniform spreading and removal of surplus wax. The slides were allowed to cool in a horizontal position. The film thickness was approximately 0.1 mm. A coated slide v-as placed on a wooden platform, 24 mm. high, contained in a cuvette, 105 by 35 by 103 mm. high, with sides of optically plane glass. A drop of the tePt solution, usually 2.0 to 2 5 mm. in diameter, was placed on the waxed slide with a 1-ml. pipet, as close as possible t o one of the long edges of the slide. A glass cove1 was placed on the cuvette. After tapping the cuvette support, it was leveled if necessary, and drop diameter and height measured
In this connection, Freundlich ( 1 1 ) proposed the factor, adhesion tension, A , which he defined A = SS - SSL Thus,
A = IVz.ir
SL cos 0
=
Adhesion tension is thus an index of immersional wetting. Further examination of Equation 2 for work of adhesion indicates TYSL =
A
+ SL
(8)
which indicates the relationship between adhesion trnsiori and work of adhesion. PROCEDURES
Surface and interfacial tensions were determined with a DuNoily interfacial tensiometer, using the Harkins and Jordan correction factors (IS). Two reference liquids were used in obtaining interfacial tensions. White mineral oil (paraffin), USP grade, 125/135 Saybolt viscosity a t 100' F., was used as representative of a nonpolar liquid. Technical grade oleic acid (red oil), specific gravity 0.883 a t 25' C., acid number 202.5, Wijs iodine number 93.0, congealing temperature (USP) 0.5' C., mineral acid number 0.17, boiling point 270" C., was the polar reference material. Tests were made in glass dishes, 2 1 / 4 inches in diameter by 1 inch in height, a t a temperature of 25" to 26' C., and with the age of the interface 45 t o 60 seconds. Elevated temperature tests were run a t 50' to 51' C. Spreading coefficients were calculated using Equation 3, modified for liquid-liquid spreading:
+
W S P= S O Z L- SL - SOIL-L where
W ~ =Pspreading coefficient S O I L= surface tension of oil on which spreading occurs S L = surface tension of spreading liquid, the surfactant S O Z L - L= interfacial tension of oil and surfactant solution A modified drop dimension method for determining contact angle was used, because it was free from the practical and timeconsuming difficulties of other standard methods (1, 4,5 ) when applied t o the study of many solutions. If a drop is so small that it can be regarded as a spheroidal segment-no appreciable gravitntion effect-it follows 0 = 2.tan-1
where z = maximum height of the drop =
radius of the base of the drop
I
R
I
4
I
I
6
I
I
8
I
/D
I N T E R F A C I A L TENSION, D Y N E W C M .
Figure 2. Contact Angle Versus Interfacial Tension of Selected Detergents in 0.401, Coiicantratio~~ 0
+
Aqueous solution 0.1% sodium sulfate
with a 20-power Brinell microscope, clamped in a permnnent horizontal position in front of the cell. Measurements were aided by the use of a 10-watt microscope lamp illuminator, with daylight filter removed, placed directly behind the drop a t the rear of the cuvette. Each contact angle reported is the average of a t least 4 drops (frequently as many as 8 to 10 drops were measured for one solution). The reproducibility of the contact angles was not worse than & l o . Temperature of testing was 25" to 27' C . The following procedure was required in calculating contact angles-tangents of one half the contact angle (uncorrected) were computed from measurements of drop height and diameter. The tangents were averaged, the corresponding value of 8/2 (uncoi rected) obtained from a table of natural trigonometric functions. and the uncorrected contact angle determined by douhling the latter. In order to apply the gravity correction, it was necessary t o know the capillary constant of the surfactant solution. This constant was computed from Laplace's equatioin
INDUSTRIAL AND ENGINEERING CHEMISTRY
December 1953
2761
TABLEI. SURFACE TENSION OF SURFACTANTS
Surfactant F a t t y acid soap Sodium oleate, USP Rosin soap Sodium resinate Alcohol sulfate Sodium lauryl sulfate
#.
(Temperature, 25O to 26' C . ) Surfactant, Surfactant Surface Tension, Surfactant, Surfactant Surface Tension, WeightDynes per Cm. WeightDynes per Cm. Volume, 0.10% 0.10% 0.10% Volume, 0.10% 0.107 0 10% % Water NazSO4 Na4PsOi CMCO % Water NazSOi NarPi8i CMCa Surfactant Polyethylene glycol fatty acid 25.0 25.2 24.7 24.9 0 1 ester 32.8 31.4 32.8 0.1 32.0 25.0 24.6 24.9 25.1 Polyethylene glycol 400 0.4 31.5 30.5 31.9 0.4 30.2 monolaurate 31.8 3 0 . 5 31.9 0.1 31.2 Product A 42.6 43.4 39.2 40.8 0.1 30.3 30.3 29.3 0.4 30.1 38.2 35.2 35.2 37.2 0.4 377 388 382 0 1 382 Polyethylene glycol tall oil 371 373 373 368 0 4 ester 33.4 32.1 32.6 0.1 32.8 34 6 36 8 36 9 0 1 35.1 3 3 . 0 31.6 32.6 0.4 32.7 Polyethyleqe glycol sorbitan 0 4 3 4 9 3 4 8 369 347 monolaurate 30.8 30.1 33.2 28.6 0.1 32.9 31.2 31.6 30.3 0.4 F a t t y amide condensation product 32.4 0.1 3 0 . 8 3 0 . 6 30.6 Product 3 30.3 31.2 0.1 32.4 31.6 30.2 29.9 30.2 0.4 30.3 30.5 30.7 31.8 0.4 31.6 27.5 27.6 27.4 0.1 27.5 Product 4 31.4 31.7 32.8 0.1 33.7 27.7 27.8 ' 2 7 . 7 0.4 27.6 31.4 31.6 32.4 0.4 33.3 44.1 44.8 49.1 46.1 0.1 Alkyl olyethylene glycol thio 35.1 36.7 37.8 36.4 0.4 etRer 28.4 28.4 28.4 0.1 28.4 31.2 31.6 34.4 35.0 0.1 Product 5 28.4 28.4 28.4 0.4 28.6 29.2 29.2 29.6 29.5 0.4 30.0 30.0 0 1 30.3 30.1 29.2 29.4 31.2 31.9 0.1 Product 6 30.1 30.4 30.3 0.4 30.8 28.5 29.4 28.6 29.5 0.4
Sodium salt of sulfated fatty acid monoglyceride Alkyl aryl sulfonate Sodium dodecylbenzenesulfonate Sodium kerylbenzenesulfonaieb Sodium isopropylnaphthalenesulfonate Sodium nionobutylphenylphenolmonosulfonate Sodium dibutylphenylghenoldisulfonate Aliphatic sulfonate Sodium dioctylsulfosuccinate Petroleum hydrocarbons, sodium aulfonate .41ky1 aryl polyethylene glycol ether p-Iso-octylphenolnonaethylene glycol p-Iso-octylphenoldecaethylene glycol
0.1 0.4 0.1 0.4
30.2 27.4 32.1 31.4
25.8 24.9 30.7 30.4
26.0 26.1 30.8 30.5
29.4 26.4 31.9 81.5
0.1 0.4 0.1 0.4
29.7 29.9 29.7 30.4.
29.7 29.8 29.8 30.1
29.6 29.7 29.9 29.8
29.6 29.8 29.8 29.8
where
a = capillary constant, cm. S L = surface tension of solution g = gravitational constant, 980 cm./sec./sec, d = solution density-taken as unity The correction was approximately + l o for all solutions under the test conditions. Work of adhesion and adhesion tension were calculated from the values of surface tension and contact angle using Equations 2 and 7. I n preparing surfactant solutions 100% active agents were used as described previously (16). The paraffin used in contact angle studies had a melting point of 52.5" C . RESULTS
u
v
The surface tension (see Tables I and 11) of most unbuilt surfactant solutions decreases in the 0.1 t o 0.4% concentration range. Several surfactants exhibit a slight increase at 0.4010, in keeping with the known phenomenon of a slight increase in tension at higher concentrations following the attainment of a minimum. Sodium oleate soap solutions have lower surface tension values than any of the surfactants studied. Nonionic detergents of the alkyl aryl polyethylene glycol ether type possess greater surface tension depressing properties than any of the anionic detergents. Seutral, polyphosphate, and sodium carboxymethylcellulose (CMC) builders in 0.1yo concentration have substantially no effect on 0.1 t o 0.4% sodium oleate soap solutions. Conforming t o the general rule that electrolytic builders tend t o decrease the surface tension of unhydrolyzed anionic surfactants, practically all such agents show a lowering of surface tension in the presence of neutral or polyphosphate builders. A sulfated monoglyceride detergent forms an exception with polyphosphate. The builders have no appreciable effect on the surface tension of alkyl aryl polyethylene glycol ether and alkyl polyethylene glycol thio ether nonionics, the effect on the other nonionic types being specific for the various builders.
Alkyl polyethylene glycol ether Oleylpolyethylene glycol ether
37.2 38.7 45.2 43.0
0.1
Solid polyethylene glycol condensatec a OPE.
0.1 0.4 0.4
38.9 38.8 44.3 42.4
38.9 38.8 44.5 42.5
39 2 39 0 45.1 42.5
CMC indicajes sodium carboxymethylcellulose, low viscosjty, 25 to 50 in 2% solution b weight at 25" C 99.5+% active material.
Cm. Keryl indicades a&yl radicals of Solid polyethylene glycol condensate is a polyoxypropylene alycolpolyoxyethylene glycol nonionic. 6 c
The surface tension of 0.4% sodium oIeate solutions increases a t p H 11 to 12, probably due to prevention of hydrolysis, since oleic acid, the product of hydrolysis, has marked surface tension
TABLE11. EFFECTOF pH ON SURFACE TEKSXOS OF 0.4y0 SURFACTANT SOLUTIONS (Temperature, 25O to 26' C.) Surface Tension, p H Normal 4 Normal 9 11 PH
Surfactant F a t t y acid soap Sodium oleate, USP Rosin soap Sodium resinate Alcohol sulfate Sodium lauryl sulfate Alkyl aryl sulfonate Sodium kerylbenzenesulfonate Sodium monobutylphenylphenolmonosulfonate Aliphatic sulfonate Sodium dioctylsulfosuccinate Alkyl aryl polyethylene glycol ether p-Iso-octylphenoldeoaethylene glycol Polyethylene glycol fatty acid ester Product A Polyethylene glycol tall oil ester Polyethylene glycol sorbitan monolaurate Fatty amide condensation product Product 4 Alkyl polyethylene glycol thio ether Product 5 Alkyl olyethylene glycol ,e,!t Oleylpolyethylene glycol ether
12
10 0
..
24.9
24.9
28.8
32.2
10 1
..
38.2
..
39.6
37.8
7.6
33.4
33.0
33.3
33.7
33 2
5 0
32.8
33.3
32.8
32.8
31.2
8 6
28.8
29.5
29.0
28.9
28.6
4 7
27.1
27.4
26.5
26.7
24.8
6 5
29.8
30.4
29.9
29.9
29.9
4.2
30.0
30.1
31.4
31.6
31.8
38.5
38.5
5 6
37.4
37.3
38.5
5 0
34.7
34.9
35.8
36.8
36.5
9.4
25.9
27.6
27.4
28.0
27.8
5 8
28.4
28.6
28.4
28.4
28.4
5 6
38.5
38.7
38.6
38.8
38.5
2762
VoL 45, No. 12
INDUSTRIAL AND ENGINEERING CHEMISTRY
TABLE111.
IXTERFACIAL
TENSION OF
SURF.4CTAXTS
(Temperature, 2;'
Surfactant Fatty acid soap Sodium oleate, USP
Surfactant, WeightVolxme,
Rosin soap Sodium resinate Alcohol sulfate Sodium lauryl sulfate Sodium salt of sulfated fatty acid monoglyceride Alkyl aryl sulfonate Sodium dodecylbenzenesulfonate Sodium kerylbenzenesulfonate Sodium isopropylnaphthalenesulfonate Sodium monobutylphenylphenolmonosulfonate Sodium dibutylphenylphenoldisulfonate Aliphatic sulfonate Sodium dioctylsulfosuccinate Petroleum hydrocarbons sodium sulfonate Alkyl aryl polyethylene glycol ether p-Iso-octylphenolnonaethyleneglycol ether p-150-oqtylphenoldecaethylene glycol
Polyethylene glycol fatty acid ester Polyethylene glycol 400 monolaurate Product A Polyethylene glycol tall oil ester Polyethylene glycol sorbitan monolaurate Fatty amide condensation product Product 3 Product 4 Alkyl polyethylene glycol thio ether Product 5 Product 6 Blkyl polyethylene glvcol ether Oleylpolyethylene &col ether Solid polyethylene glycol condensate
YO
AGAIXST PARAFFIX OIL A S D
REDOIL
t o 26" C . )
Interfacial Tension, Dynes per Cm. -~ Against Paraffin 011, Against Red Oil, Surfactant in Surfactant in 0.10% 0.10% 0.10% 0.10% 0.10% 0.10% Water NazSOa NarPz01 C M C Water NazSOa SaiP?Oi C h I C
0.1 0.4
2.7 1.9
2 7 1 4
2.7 1.5
2.7 1.6
5.3 5.7
4.4 4.9
5.4 5.2
4.8 5.2
0.1 0 4
19.9
15,l 7.8
17 1 8.4
16.6
6.9 5.2
... 4.0
7.6 4.4
...
. 00 .. 41
9.7 9.0
7.2 6.4
7.2 8.0 8.2 8.0
8.4 8.6 8.8 7.7
1.7 0.5
0.2 0.2 0.2 0.2
0.2 0.2 0.3 0.2
0 2 0.1
0.1 0.4
7.1 7.8 7.6 7.1
0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4 0 1 0 4
3.8 4.3 6.0 5.7 21.4 10.6 10.9 2.8 5.4 2.7
3.8 3 8 4.2 4.2 18.2 9.9 6.9 2.3 2 0 1.6
4 6 1 3 4.9 4.6 19.2 10 E I .0 2.3 2 8 1.5
5.3 4.9 6.1 5.7 22 2 12.2 10.0 2.6 4.6 2.2
1.9 0.5 1.3 0.4 5.7 2.5 3.8 2.1 2.6 1.6
1.3 0.2 1.2 0.4 4.8 1.3 2.8 1.3 2.9 1 2
1 9 0.5 2.0 0.5 5 7 2.3 5.2 2.1 4.0 1.8
1.6 0.5 1 3 0.3 5.9 2.0 3.8 1.8 2 7 1.2
0.1 0.4 0.1 0.4
5.4 3.5 6.8 5.5
2.0 1.3 4 9 4.8
2.3 1.1 5.5 4.8
6.3 3.0 5.6 5.5
1.8 1.2 2.0 1.0
1.6 2.5 1.2
1.1
2.2 1.6 3.2 1.3
1.8 1.2 2.2 1.0
0,1
2.8 2.3 3.2 2.8
2.7 2.3 3.2 2.6
2.8 2.3 3.1 2.8
2.7 2.3 3.0 2.7
3.9 3.3 3.8 3.2
3.3 8.1 3.3 3.1
5.4 4.2 6.2 3.8
5.0 3.9 4.9 3.8
5.0 4.0 6.6 4.2
5.2 4.2 6.0 5.4 7 1 6.4 7.8 6.7
6.4 5.9 6.4 5.0 7.1 6.4 7.4 7.1
6.3 5.5 8.3 5.7 7.2 6.7 7.2 6.8
4.4 3.9 4.2 3.9 3.4 2.5 1.8 1.1
3.1 3.1 3.3 3.2 3.1 2.2 1.6 0.9
6.8 5.4 6.7 4.8 5.0 3.4 2.3 1.0
4.1 4.0 4.5 4.0 3.4 2.6 1.7 1.1
7.8 7.8 0 9
0.4
8.1 8.2 0.7 1.0
0 8
8 0 7.9 0.7 0.7
8.5 7.8 0.8 0.8
3.9 3.3 5.8 3.6
3.3 3 2 4.5 3.4
4.2 3.3 5.0 3.1
7.1 4.5 5.3 3.8
0.1 0.4 0.1 0.4
3.2 1.6 3.5 2.9
3.2 1.4 3.9 2 9
3.1 1.4 4.0 2.7
3.0 1.3 3.9 2.7
4.: 3.6 3.6 3.2
3.8 4.1 3.1 3.6
6.7 5.9 5.7 4.4
3.7 5.2 5 0 3.7
0.1 0.4
8.0 7.6 18.3 16 3
7.6 7 2 17 0 15 5
7.7 7.2 16.8 14.6
7.9 7.4 16.7 15.0
2.6 2.1 2.9 1.3
2.2 1.8 2.9 1.3
3.6 2.2 2.8 1.7
3.4 2.1 3 0 1.7
0.4
S!?
U.4
0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4
0 1
0 1 0 4
9.2
6.9 6.7 7.4 6.9
depressing properties. Other anionic surfactants w t h the eweption of sodium lauryl sulfate exhibit a progressive decrease in surface tension with increase in pH. This is similar to the effect on surface tension usually found with builders. Effects of pH on nonionic agents are specific for the various types. The interfacial tension (see Tables I11 and IV) against paraffin oil of most anionic surfactants is decreased by neutral and polyphosphate builders, exceptions being 0.1 % sodium oleate soap, a sulfated f a t t y acid monoglyceride and sodium dodecylbenaenesulfonate. Practically all nonionic surfactants in the 0.1 t o 0.4% concentration range are unaffected by neutral, polyphosphate, and sodium carboxymethylcellulose (CMC) builders; esceptions are polyethylene glycol fatty acid esters that show no trend, and the solid nonionic agent whose interfacial tension against paraffin oil is decreased by all three builders. Sodium oleate soap and the alkyl aryl polyethylene glycol ether nonionics have substantially lower interfacial tensions against paraffin oil in built and unbuilt solutions than anionic detergents. Most built anionic wetting agents have considerably lower interfacial tensions against paraffin oil than built anionic detergents.
0.4 0.2
,..
1.0 0.4
Snionic alcohol sulfates and alkyl aryl sulfonate detergents (sodium dodecylbcnzcncsulfonate and sodium kerylbenzene sulfonates) have considerably loTyer interfacial tensions against polar red oil in built and unbuilt solutions than sodium oleate soap and nonionic surfactants. This is the reverse of the results against nonpolar paraffin oil. Built anionic wetting agents (sodium monobutylphenylphenol-monosulfonate, and sodium dioctylsulfosuccinate) have much higher interfacial tension values against red oil than built anionic detergents of the alcohol sulfate and alkyl aryl sulfonate types, again the reverse of results against paraffin oil. The interfacial tensions against red oil of the alkyl aryl polyethylene glycol ether and alkyl polyethylene glycol thio cther nonionics are increased appreciably by polyphosphate and sodium carboxymethylcellulose (CMC) builders, while those of polyethylene glycol fatty acid ester and polyethylene glycol tall oil ester nonionics are substantially increased by polyphosphate builder. Neutral builder reduces appreciably the interfacial tensions against red oil of 0.1% alkyl aryl polyethylene glycol ether and 0.1 to 0.4% polyethylene glycol fatty acid ester nonionics, and also 0.1 to 0.4% sodium oleate soap.
December 1953
*
INDUSTRIAL AND ENGINEERING CHEMISTRY
2763
soap, a polyethylene glycol tall oil ester and a solid nonionic The interfacial tension of sodium oleate soap against paraffin surfactant. oil increases at pH 11to 12, paralleling the increase in surface tenA 0.1% ’ neutral builder sodium sulfate (NazSOa)decreases the sion a t the same hydroxyl ion concentration. The increase may contact angles of 0.1% solutions of anionic wetting agents of the be explained a.s due to the predominating effect of the hydroxyl alkyl aryl sulfonate type, but it caused no significant changes in ions in suppressing hydrolysis, and more than counteracting the 0.4% solutions. This builder also decreases the contact angles simultaneous tendency of the added sodium hydroxide t o lower of rosin soap and sodium dioctylsulfosuccinate, but it gives inthe interfacial tension. The interfacial tensions of the other creased angles in 0.1% solutions of nonionics of the alkyl aryl anionic surfactanb against paraffin oil are decreased when the p H polyethylene glycol ether and polyethylene glycol fatty acid ester is raised t o 12, again indicating that increasing the p H is actually types. the addition of alkaline builder. Interfacial tensions against A 0.1 % polyphosphate builder increases appreciably the conparaffin oil of mast nonionic agents are unaffected by increasing tact angles of 0.1% solutions of alcohol sulfate and alkyl aryl pH. Interfacial tension against polar red oil of sodium oleate polyethylene glycol ether surfactants. Under these conditions, decreases sharply between p H 11 and 12. This could be due t o slight increases in contact angle are shown by 0.1 t o 0.4% sodium formation of soap in the interface, with the tensiometer indicating oleate and 0.1% alkyl aryl sulfonate detergents; a n appreciable an interfacial tension between sodium oleate and partial sodium decrease in contact angle is shown by sodium dioctyl sulfosuccioleate layer formed by neutralization of oleic acid with excess nate, as in the case with sodium sulfate builder. alkalinity present in the aqueous layer; at p H 12, more sodium There is no instance of a significant decrease in the contact oleate is formed than at p H 11. I n contrast t o results with parafangle of a surfactant solution due to added sodium carboxymethfin oil, the interfacial tensions against red oil of several types of ylcellulose (CMC) builder. This builder increased appreciably nonionic surfactants decrease sharply a t p H 12. the contact angles of 0 1% solutions of anionic detergents of the Sodium oleate soap has greater spreading coefficients (see Taalcohol sulfate and alkyl aryl sulfonate types; slight increases in bles V and VI) on paraffin oil than the other types of surfactants angle are exhibited by 0.1 t o 0.4% sodium oleate, 0.1 % rosin soap, studied. With the exception of a n anionic wetting agent, sodium and 0.1 % alkyl aryl polyethylene glycol ether nonionics. dioctyl sulfosuccinate, the same is true of spreading coefficients There appears t o be no general effect of p H on contact angle. 011 polar red oil. At 0.4% concentration, anionic wetting agents (sodium monobutylphenylphenolmonosulfonate and sodium diocHowever, in O.4y0 sodium oleate solutions, the contact angle doubles as the p H is increased from 10 to 11. tylsulfosuccinate) possess considerably greater spreading coefI n 0.1 to 0.470unbuilt solution, rosin soap, anionic detergents ficients on both paraffin and red oils than anionic detergents of of the alkyl aryl sulfonate type, and nonionics of the alkyl aryl the alcohol sulfate, alkyl aryl sulfonate, and aliphatic sulfonate polyethylene glycol ether and alkyl polyethylene glycol thio ether types. All types of builders increase the spreading coefficientimprove the spreading wetting-on paraffin oil of 0.4% solutions types show the highest works of adhesion for nonpolar paraffin surfaces, all substantially greater than those of sodium oleate of anionic wetting agents, while the spreading coefficient of anionic soap. There is no correlation between work of adhesion and detergents on paraffin oil is not affected appreciably. On polar red oil, all types of builders increase the spreading tendencies of contact angle. anionic detergents (alcohol sulfate and alkyl aryl sulfonate types) The 0.1% sodium sulfate builder decreases the works of adhesion of 0.1 t o 0.4% solutions of alkyl aryl sulfonate detergents, as well as anionic wetting agents. While the alkyl aryl polyand of 0.1% solutions of nonionics of the alkyl aryl polyethylene ethylene glycol ether nonionics have greater spreading tendencies than anionic synthetic detergents on paraffin oil, no such,supeglycol ether and polyethylene glycol fatty acid ester types. riority exists on red oil. T h e s p r e a d i n g coefficient of anionic wetting agents is TABLE IV. EFFECT OB p H ON INTERFACIAL TENSION OF 0.4% SURFACTANT SOLUTIONS improved a t p H 12 on both (Temperature, 25O t o 26’ C.) polar and nonpolar oils, due Interfacial Tension, Dynes per Cm. in parl t o a decrease in sur~~~~~l Against Paraffin Oil, p H Against Red Oil, p H face tension at higher alkaSurfactant 4 Normal 9 11 PH 12 4 Normal 9 11 12 linity. The spreading wetF a t t y acid soap ting properties of 0.4% sodium Sodium oleate. C S P 10.0 17.5 1.5 2.1 4.0 4.1 ... 5 . 7 5 . 4 5 . 8 1 . 3 o l e a t e s o a p s o l u t i o n drop Rosin soap Sodium resinate 10 1 ,., 9,2 ... 1 0 . 8 6 . 7 5.2 ... 5 . 6 1 . 5 sharply a t p H 11 to 12, due Alcohol sulfate t o increases in surface and Sodium lauryl sulfate 7.6 8.5 9.0 8.4 8.5 7.7 0.1 0.2 0.2 0.2 0.2 interfacial tensions at the Alkyl aryl sulfonate Sodium kerylbenzene sulfonate 5.0 5.9 5.7 5.9 5.9 3.2 0.3 0.4 0.4 0.4 0.6 higher alkalinities. Sodium monobutylphenylI n 0.1 to 0.4% unbuilt soluphenolmonosulfonate 8 6 2 4 2.8 2.5 2.5 2.4 1.8 2.1 1.5 2.1 1.3 tion on nonpolar paraffin wax Aliphatic sulfonate ... 3 . 5 3 . 3 1 . 2 1 . 2 0.9 1 . 2 0 . 9 0 . 9 0 .9 4 . 7 Sodium dioctylsulfosuccinate surfaces, sodium oleate forms Alkyl aryl polyethylene glycol considerably smaller contact ether p-Iso-octylphenoldecaethylene angles than any other surfac6 5 2.7 2.8 2.7 2.7 2.7 2.6 3.2 2.3 2.3 1.6 glycol tant studied (see Tables VI11 Polyethylene glycol fatty acid ester and IX). Under these condi4.2 ... 4 . 2 4 . 3 5 . 5 5 . 5 3 . 3 3 . 9 3 . 4 4 . 5 1 . 3 Product A tions, nonionics of the alkyl Polyethylene glycol tall oil ester 5.6 6.3 6.7 6 , 8 6.8 6.8 ... 2.5 2.0 2.1 2.3 aryl polyethylene glycol ether Polyethylene glycol sorbitan 5.0 6.9 6.9 7.6 7.7 7.7 monolaurate 0.8 1.1 0.9 1.1 1.6 and alkyl polyethylene glycol F a t t y amide condensation product thio ether types give appreProduct 4 9.4 0.8 1.0 . . . 0 . 8 0 . 8 3 . 2 3 . 6 ... 2 . 8 1 . 1 c i a b l y s m a l l e r angles than Alkyl olyethylene glycol thio etger a n i o n i c d e t e r g e n t s of t h e Product 5 1.6 1.4 1.4 5.8 1.3 1.4 3.7 3.6 3.1 3 3 3 4 alcohol sulfate and alkyl aryl Alkyl polyeth lene glycol ether sulfonate types. Large Oleylpolyetgylene glycol ether 7.6 7.3 7.3 5.6 7.3 7.3 2.4 2.1 2.3 2.1 1.6 angles are formed by rosin
...
91
II
2764
Vol. 45, No. 12
INDUSTRIAL AND ENGINEERING CHEMISTRY
TABLE T-
S P R E A D I N G C O E F F I C I E N T O F S U R F A C T A X T S O N P A R A F F I N 011, ?.XD IIEl)
-
_-
Surfactant Fatty acid soap Sodium oleate, USP Rosin soap Sodium resinate Alcohol sulfate Sodium lauryl sulfate
Sodium salt of sulfated fatty acid monoglyceride Alkyl aryl sulfonate Sodium dodecylbenzene sulfonate Sodium kerylbenzenesulfonate Sodium isopropylnaphthalenesulfonate Sodium monobutylphenylphenolnionosulfonate Sodium dibutylphenylphenoldisulfonate Aliphatic sulfonate Sodium dioctylsulfosuccinate Petroleum hydrocarbons sodium sulfonate 41kyl aryl polyethylene glycol ether n-Iso-oct ylphenolnonaetliylene glycol ether p-Iso-octylphenoldecaethylene glycol Polyethylene glycol fatty acid ester Polyethylene glycol 400 monolaurate Product A Polyethylene glycol tall oil ester Polyethylene glycol sorbitan monolaurate F a t t y amide condensation product Product 3 Product 4 Alkyl polyethylene glycol thio ether Product 5 Product 6
OIL
(Temperature, 25' to 26' C . ) Spreading Coefficient, Ergs per Sq. Cm. Surfactant, On Paraffin Oil&, Surfactant in On Red Oil b, Surfactant in WeightVolume, 0.10% 0.107 0.10% 0.10% 0.10% 0.107 Water NazSOl NarPgO; ChIC" Water XanSOa ~ a 4 ~ 2 6CMC 7 % 0.1 0.4
+2 4 f3.3
f2.2 f3 6
f2.7 f3.6
C2.5 1 3 9
f2.0 fl.6
+1.5 f1.4
-7.6
-18.6 -8.0
-0.7 -0.2 4-1.3 +1.1
-1.2 -1.2 -1.9
-2.7 -0.6 -3.4 -2.1 -20.2 -7.3 -7.2 zero -2.9 $0.5
aero fO.9 -1.0 -0.2 -17.3 -4.8 -2 4 +1.1 -0.5 f1.8
-1.5 fO.4 -2.1 -0.5 -18.9 -7.4
fO.3 -1.8 f1.3
-1.6 -0 5 -2 5 -1.3 -23 4 -8.0 -6 6 i o2 -2.3 +1 0
f0.I -7.4 -6 9
-0.4 f3.0 -2.5 -0.8
+4.2 +5.6 -1.6 zero
i3.4 f4.9 -2 4 -0 2
f0.4 f4.0 -2.5 -0.9
-2 2 -2 0 -2 7 -2 4
-2.0 -1.6 -1.9 -2.0
-1.4 -1.3 -1.5 -1.6
-3 4 -2.3 -3.5 -2.0
-3.0 -2.1 -3.1 -2.0
-4.8 -2.5 -3.8 -2.4 -10.0 -8 2 -5,3 -4.1
-2.9 -2.0 -2.2 -0.9 -9.2 -7.4 -4.6 -4.1
-8.0 -5,7 -7 0 -3 5 -12.2 -8.9 -7.5 -6.3
-3.9 -4.7 -2.7 -10.0 -8.3 -7.0 -4.2
-3.1 -2.0 -1.7 f0.4
-2.3 -1.8 -0.4 fO.4
-3.2 -1.6 -1.0 f0.8
-7.9 -3.1 -l.i f O . 1
-1.3 -0.6 -2.3 -2 4
-0.6 -0.9 -1.6 -2.4
-3.5 -2.7 -4.1 -3.1
-2 5 -2.0 -3 4 -2.2
0.1 0.4
-29.0 -17.3
-25.8 -13.0
-29.6 -12 5
-17
0.1 0.4 0.1 0.4
-13.0 -11.9 -7.4 -7.9
-9.1 -9.3 -7.6 -7.3
-9.7 -10 5 -11.3 -10.8
-11.1 -11.2 -7.3
0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4
-6.1 -5.8 -9.6 -8.9 -37.4 -16 9 -15.8 -2.2 -7.2 -2.1
-4.0 -4.2
-5.7 -4.9 -6.5 -6.1 -33.9 -17.2 -9.0 -1.4 -2.1
-6 8 -6.4 -8.8 -8.0 -41.2 -19.7 -14.3 -2.1 -5.7 -1.5
0.1 0.4 0.1 0.4
-5.5
0.1 0.4 0.1 0.4
-2
4
-2 -2 -3
8 1
-0.8 -8.8 -6.8
1
-5.5
-5 5 -32.2 -14.9 -8.0 -1.4 -1.1
-0.1
+2.3 f3.9
-5.5 -5.1
-2 3 -2 0 -2 9 -2 6
+o
1
f1.8 f3.9 -6.2
-5.2 -2 -1
3
-2
5
-2
9 9
f1.3 +1.0
1
-8.8
-5.6
~~
-14.5 -11.8
-2.2 -1 6 -0.4 -0.5
f1.9 fl.5
-1.2 -1.2 f2.0 zero
-1.5
--5.2
0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4
-6.9 -4.1 -7.7 -4.2 -155.0 -13.9 -12.4 -11.7
-6 5 -4.6 -6.4 -4.6 -14 7 -13.1 -12.0 -11.4
-15.8 -13.4 -14.1 -13 9
-9.0 -6.9 -10.0 -5.9 -15.3 -13.9 -14.0 -11.4
0.1 0.4 0.1 0.4
-8.8 -8.4
fl.9 f1.5
-8.3 -7.9 f1.7 +1.5
-8.6 -7 7 f1.8 f1.7
-10.8 -7.9 fl.9 f1.6
-1.5 -0.1 -3.7 -3.6
10.3 -3.9 -3.2
-1.5
-1.4 +0.3 -3.9 -3.1
-15.1 -16.2
-16.4 -15.9
-16.5 -i5.9
-17.0 -16.3
-8.2 -9.2
-9.5 -9.0
-10.9 -9.4
-11.0 -9.3
-33.4 -29.2
-31.5 -27.8
-31.2 -27.0
-31.7 -27.4
-16.5 -12.7
-15.6 -12.1
-15.7 -12.6
-16.5 -12.6
0.1 0.4
0.1 0 4
Alkyl polyethylene glycol ether Oleyl polyethylene glycol 0.1 0.4 ether Solid polyethylene glycol con0.1 densate 0.4 Suiface tension a Paraffin oil, 30.1 dynes per em. b Red oil, 31.6 dynes per ern.
Works of adhesion of rosin soap and the solid nonionic agent are increased by sodium sulfate, while those of sodium oleate are unaffected. A 0.1% polyphosphate or sodium carbosymethylcellulose (CMC) builder decreases the works of adhesion of sodium oleate, of anionic detergents of the alkyl aryl sulfonate type, and of nonionics of the alkyl aryl polyethylene glycol ether and alkyl polyethylene glycol thio ether types. While no correlation is evident between adhesion tension and work of adhesion, with few exceptions high adhesion tension corresponds to small contact angle. CONCLUSION
Because of the variety of available surfactant and builder types, it is important t o note the generalizations indicated here for the physicochemical factors studied, as well as the specificity exhibited by the different types of Burfactants and surfactant-builder
-9.1 -7.7 -8.2 -5.2
-1.3 io.4 -3.8 -2.7
-5.3
combinations. Limited correlation has been found between contact angle and surface tension and between contact angle and interfacial tension, the correlation being limited to a group of important surfactants, built and unbuilt. From a consideration of the equilibrium forces a t a solid-liquid-air interface, it follows from Equation 1 that cos e = 8 s -
SSL
SL
ilsvuming no changes in the solid and solid-liquid tension values, the smaller the solution surface tension, the smaller the contact angle, and the greater the wetting. This assumption is not always valid, and therefore surface tension has not been an accepted index of wetting. However, in this investigation i t was found that: Sodium oleate forms considerably smaller contact angles on paraffin than any other surfactant, while alkyl aryl polyethylene
December 1953
INDUSTRIAL AND ENGINEERING CHEMISTRY TABLE
OF p H VI. EFFECT
ON
2765
SPREADING COEFFICIENT O F 0.470 SURFACTANT SOLUTIOSS (Temperature, 25” t o 26’ C.)
1
.
Surfactant F a t t y acid soap Sodium oleate, USP Rosin soap Sodium resinate Alcohol sulfate Sodium lauryl sulfate Alkyl aryl sulfonate Sodium kerylbenzenesulfonate ’ Sodium monobutylphenylphenolmonosulfonate Aliphatic sulfonate Sodium dioctyl sulfosuccinate 41kyl aryl polyethylene glyco lether p-Iso-octylphenoldecaethyleneglycol Polyethylene glycol fatty acid ester Product A Polyethylene glycol tall oil ester Polyethylene glycol sorbitan monolaurate F a t t y amide condensation product Product 4 -41kyl polyethylene glycol thio ether Product 5 Alkyl polyeth lene glycol ether Oleylpolyetxylene glycol ether
Normal PH
Spreading Coefficient, Ergs per Sq. Cm. On Paraffin Oil, at pH of On Red Oil, a t p H of Normal 9 11 12 4 Normal 9 11
4
10.0
$3.3
10.1
$3.1
-17.3
-2.7
-6.2
$1.0
-20.3
-14.4
-11.8
$1.3
12’
-3.0
-1.9r
-13.6
-7.7
7.6
-11.8
-11.9
-11.6
-12.1
-10.8
-1.9
-1.6
-1.9
-2.3
-11,s
5.0 8.6
-8.6 -1.1
-8.9 -2.2
-8.6 -1.4
-8.6 -1.3
-4.3 -0.9
-1.5 $1.0
-2.1
-1.6 $0.7
-1.6 $0.6
-01.2 $11.7
-0.8
$0.3
$2.2
f4.1
$3.6
+3.0
$4.2
$4.0
S5.9’
4.7 6.5
zero
-2.4
-3.1
-2.5
-2.5
-2.5
-0.8
-2.0
-0.6
-0.6SO.1
4.2 5.6 5.0
-12.6 -11.5
-4.2 -13.9 -11.7
-5.6 -15.2 -13.3
-6.9 -15.2 -14.4
-7.2 -15.2 -14.1
-1.7 -3.9
-2.4 -8.2 -4.4
-3.2 -8.9 -5.1
-4.4 -9.0 -6.3
-1.B. -9.2 -6.5
9.4
+3.4
$1.5
$1.3
$1.5
S2.5
$0.4
$0.8
$2.7
5.8
+0.4
-0.1
$0.3
4-0.3
+0.3
-0.5
-0.6
$0.1
-0.1
-0.2’
5.6
-15.7
-16.2
-15.8
-16.0
-15.7
-9.3
-9.2
-9.3
-9.3
-8.5
OF TEMPERATURE ON SURFACE AND INTERFACIAL TENSIONS AND SPRBADING COEFFICIENTOF 0.49;b TABLE VII. EFFECT SURFACTANT SOLUTIONS
Surface Tension, Dynes per Cm. 25O C. 50° C.
Surfactant F a t t y acid soap Sodium oleate, USP Rosin soap Sodium resinate
e
.yl sulfate Aliphatic sulfonate Sodium dioctylsulfosuccinate Alkyl aryl pol ethylene glycol ether p-Iso-octylp%enoldecaethylene glycol Polyethylene glycol fatty acid ester Product A Polyethylene glycol tall oil ester Polyethylene glycol sorbitan monolaurate F a t t y amide condensation product Product 4 Alkyl polyethylene glycol thio ether Product 5 Alkyl polyeth lene glycol ether Oleylpolyetgylene glycol ether
i l
mate
24.9
23.4
1.9
1.3
$3.3
38.2
36.6
9.2
11.5
- 17.3
+2.8
5.7
5.1
$1.0
+0.7
-20.6
5.2
4.5
-11.8
-11.9
33.0
32.0
9.0
9.1
-11.9
-13.6
0.2
0.2
-1.6
-3.0
33.3 29.5
31.6 28.1
5.7 2.8
6.4 2.1
-8.9 -2.2
-10.5 -2.7
0.4 2.1
0.4 2.5
-2.1
zero
-2.8 -1.4
27.4
27.0
3.5
4.9
-0.8
-4.4
1.2
0.9
$3.0
$0.9
30.4
28.3
2.8
2.1
-3.1
-2.9
3.2
7.1
-2.0
-6.2
30.1 37.3 34.9
27.7 33.4 29.8
4.2 6.7 6.9
2.2 4.6 3.2
-4.2 -13.9 -11.7
-2.4 -10.5 -5.5
3.9 2.5 1.1
3.8 3.3 1.3
-2.4 -8.2 -4.4
-2.3 -7.5 -1.9
27.6
25.9
1.0
0.7
$1.5
$0.9
3.6
4.4
+0.4
-1.1
28.6
27.1
1.6
1.6
-0.1
-1.2
3.6
6.9
-0.6
-4.8
38.7
34.8
7.6
4.8
-16.2
-12.1
2.1
2.5
-9.2
-8.1
glycol ether and alkyl polyethylene gfycol thio ether nonionic@ form smaller contact angles than anionic detergents of the alcohol sulfate and alkyl aryl sulfonate types. Alkyl aryl polyethylene glycol ether and alkyl polyethylene glycol thio ether nonionics have lower surface tensions in built and unbuilt solutions than any anionic detergent except sodium oleate. Alkyl aryl polyethylene glycol ether and alkyl polyethylene glycol thio ether nonionics have lower interfacial tensions against paraffin oil than any anionic detergent except sodium oleate. Thus, for the group of important anionic and nonionic detergents (as distinguished from wetting agents) just mentioned, there is a direct relationship between wetting power as measured by contact angle and either surface tension or interfacial tension. Alkyl aryl polyethylene glycol ether and alkyl polyethylene glycol thio ether nonionics are of importance in metal cleaning applications because of their stability in alkaline solution at elevated temperature. While no correlation was found between work of adhesion and contact angle, some degree of correlation existed between work of adhesion and solution surface tension-the higher the surface tension, the higher the work of adhesion or adhesional wetting. While this seems anomalous, it follows from Equation 2,
wsL= sL + S~.COS e
Red Oil Interfacial Tension Spreading Coefficien 25‘C. 50” C. 25’C 50° C.
Paraffin O i l Interfacial Tension Spreading Coefficient 5OOC. 25’C. 50°C. 25’C.
Work of adhesion has gradually assumed the meaning of preferential wetting in the sense that a solution with a high work of adhesion will displace one with a lower work of adhesion from a surface, The fair correlation existing between adhesion tension and contact angle indicates that in Equation 7 for adhesion tension, the more significant factor is the contact angle,
A
=
SLCOS 8
ACKNOWLEDGMENT
Acknowledgment is made for the cooperation and advisory assistance of fellow workers of the Paint and Chemical Laboratory, Aberdeen Proving Ground, Md., C. F. Pickett, chief, and Meyer Rosenfeld; also to Rebecca Flickinger for help in obtaining many of these data. LITERATURE CITED
(1) Ablett, R., Phil.Mag., 46, 244 (1923).
(2) A d a m , N. K., “ T h e Physics a n d Chemistry of Surfaces,” 3rd ed., p. 178,London, Oxford University Press, 1941. (3)Ibid., p. 201. (4) A d a m , N.K.,a n d Jessop, G., J . Chem. Soc., 127, 1863,1925. (5) A d a m , N. K., a n d Morrell, R. S., J. Soc. Chem. Ind., 53, 255T
(1934). (6) Atlas Powder Co., Wilmington, Del., “Atlas Surface Active Agents,” 2nd printing, p. 26.
INDUSTRIAL AND ENGINEERING CHEMISTRY
2766
Vol. 45, No. 12
ANGLE,WORKOF ADHESION,ADHESIONTENSIOP TABLE T W I . CONTACT (Temperature, 25‘ t o 27’ C.)
‘g!:&Ftt’ Volume,
%
Surfactant F a t t y acid soap Sodium oleate, USP Rosin soap Sodium resinate Alcohol sulfate Sodium lauryl surfate Sodium su1fat.e fatty acid monoglyceride Alkyl aryl sulfonate Sodium dodecylbenzenesulfonate Sodium kerylbenzenesulfonate Sodium isopropylnaphthalenesulfonate Sodium monobutylphenylphenolnionosulfonate Sodium dibutylphenylphenoldisuifonate Aliphatic sulfonate Sodium dioctylsulfosuccinate Petroleum hydrocarbons, sodium sulfonate Alkyl aryl polyethylene glycol ether p-Iso-octylphenoldecaethyle n e glycol p-Iso-octylphenolnonaethylene gl col ether Polyetxylene glycol fatty acid ester Polyethylene glycol 400 monolaurate Product A Polyethylene glycol tall oil ester Polyethylene glycol sorbitan monolaurate F a t t y amide condensation product Product 3
30.8’ 28.3
46.5 46.8
21.5 21.9
30.8’ 30.0
46.9 46.8
21.7 21.7
33.0O 32.4
45.4 46.1
20.7 21.1
33.0’ 33.0
45.8 45.2
209 20.6
0.1 0.4
73.4 64.3
50.4 54.8
112 16.6
65.6 53.4
57.7 56.2
16.9 21.0
80.6 63.8
49.6 50.8
7.0 15 6
77.8 64.6
52.6 53.2
9.2 16.0
0.1 0.4 0.1 0.4
58.5 66.4 62.7 63.8
50.9 46.2 44.2 45.6
17.5 13.2 13.9 14.0
63.0 64.2 62.4 50.2
46.7 45 3 44.0 49.7
14.6 13.7 13.9 19.4
66.6 67.8 70.2 66.4
45.5 44 9 44.5 46.1
12.9 12 3 11.3 13.2
68.0 67.2 73.0 65.2
45,i 45.4 370 44.3
12.3 12 7 8 4 13 1
0.1 0.4 0.1 0.4 0.1 0.4 0.1 0.4
55.1 52.3 55.6 60.8 87.2 66.9
50.9 50.9 52 7 49.2 48.4 50.7 48.9 49.5 51.0 51.0
18.5 19 3 19.0 16 2 2 3 14.3 13 9 20 0 19 1 21 5
56.4 53.2 56.8 56.4 81.4 65.4 60.4 44.2 49.2 44.2
47 48 48 48 50 49 46 50 48 49
60.6 57.8 59.8 57.6
20.4 18.4 20.8
62 6 60 6 63 8 61 4 87 8 68 4 72 4 46 4 58 6 46 4
46.1 47.1 47.3 47.9 51.0 51.4 44.8 50.0 47.6 49.7
14 5 15 . 5 14. .5
67.8 65.2 45.6 51.4 43.2
46.5 47.1 47.6 48 5 47.4 50.6 44.8 40.6 47.8 49.3
15.3 16 4 15.9 16.9 3.1 13.9
1
16 8 18.3 17.2 17.4 6.6 14.6 15.4 20.9 19.1 20.5
1 4 13.8 10.4 20.4 16.3 20 3
185
21.2 16.7 18.6
33.4 29.4 58.6 55.0
47.3 46.6 467 47.9
21.5 21.7 16.0 17.5
36.2 25.6 58.2 56.4
47.0 47.7 47.0 47.4
21.0 22.6 16.2 16.9
560 39.0 646 58.4
45.8 46.9 45.6 48.0
16.4 20.5 13.7 16.5
66.6
0.1
0.4
47.3 53.2 43.6
0.1 0.4
62.3 39.4
1
8
6 8 7 7
6 1
3
86.0
1.7.2
15 R
0.1 0.4
60.8
53.6
48.7 48.6 47.8 ,50.0
0.1 0.4 0.1 0 4
45.5 46.8 45.6 49.8
50.5 51.2 50.5 49.2
20.8 20.8 208 19.3
51.4 500 50.9 49.0
48.4 49.4 48.4 49.3
18.6 19.3 18.7 19.5
54.2 52.0 51.4 48.8
47.4 48.1 48.1 49.3
17.5 18.3 18.5 19.6
50.4 49.6 50.2 49.6
48.8 49.1 48.5 49.1
19.0 l9,3 189 19.3
0.1 0.4
61.0 56.6 56.6 59.4 75.0 69.2 70.6 71.0
47.5 46.8 48.4 45.4 48.1 50.5 46.8 46.3
15.5 16 6 17.2 15.3 9.9 13.2 11.7 11.4
64.8 62 2 61.6 56 6 72.4 68.0 72.4 70.0
44 8
44 7 45.0 45 4 49.1 50.6 45 1 46 7
13.4 14.2 14.5 16.1 11.4 13,s 10.5 11.9
69.6 66.8 62.0 62.6 75.2 73.2 73.8 74.6
44.3 44.5 46.9 44.2 48.7 47.8 47.1 46.7
11 5 12 6 15.0 13 9 9 9 10 7 10 3 9 8
66.4 63.6 61.4 56.6 75.0 74.0 72.6 70.6
45.9 45.5 47.0 47.0 48.1 47.6 47.6 46.3
13.1 14.0 15 2 16 7 9.9
64.8 58.3 43.0 44.6
43.9 46.2 47.6 47.3
13.1 15.9 20.1 19.7
62.2 56.8 42.6 45.4
44.9 46.8 47.8 47 3
24.3 16.6 20.3 19.5
71.8 59.0 44.8 45.8
413.2 45.3 47.2 47.0
9.6 15.4 19.6 19.3
76.8 65.4 46.4 46.6
39.8 42.8 46.3 46.7
7.4 12.6 18.9 19.0
0.1
0.4
43.0 41.2 38.2 49.8
49.2 50.1 541 50.6
20.8 21.5 23.8 19.8
43.6 42.2 52.0 51.1
48.9 49.4 486 49.5
0.5 21.0 18.5 19.1
46.6 46.2 55.4 50.8
47.9 48.1 47.0 49.4
19.5 19.7 17.0 19.1
47.0 43.4 52.0 49.2
47.8 49.1 48.5 49.6
19.4 20.7 18.5 19.6
0.1 0.4 0.1 0.4
76.4 74.4 88.2 83.4
45.9 49.1 466 47.9
8.7 10.4 1.4 4.9
76.4 73.8 82.8 80.6
480 49.6 498 493
9.1 10.8 5.5 6 9
73.2 72.6 87.0 85.8
50.1 50.4 46.8 45.6
11.2 11.6 2.3 3.1
77.8 75.2 87.4 86.8
47;2 48.9 47.1 44.9
8 3 9.9 2.0 2 4
0.1
0.4 0.1 0.4 0.1 0.4 0. I
0.4 0.4
Alkyl pol ethylene thio e d e r Product 5
10 3
11.0 11.6
glycol 0.1 0.4
Product 6 Alkyl polyethylene glycol ether Oleylpolyethylene glycol ether Solid polyethylene glycol condensate a
0.1 0.4
0.1
Product 4
Surfactant in Water Surfactant in 0.1% NaaSO4 Surfactant in 0.1% iVaaPa07 Surfactant in 0.1% CAIC Contact Work of Adhesion Contact Work of Adhesion Contact Work of Adhesion ‘Contact Work of.Idhesioil angle adhesion tension angle adhesion tension angle adhesion tension angle adhesion tension
Work of adhesion and adhesion tension values in ergs per sq. cm. on paraffin wax.
TABLEIX. EFFECTOF pH ADHESIOS,
AND
O N CONTACTANGLE, WORK OF ADHESION TEIVSION OF 0.4% SURFACTANT SOLUTIONS~
(Ternperatuie. 25’ to 27” C.) Contact Work of Adhesion Surfactant pH Angle Adhesion Tension 8 30.4O . . .. ._ _ . F a t t y acid soap 9 31.2 46.2 21.3 Sodium oleate, USP 106 28.3 46.8 21.9 11 57.2 44.4 15 6 12 58.8 48.9 16.7 47.6 14.2 4 64.8 Alcohol sulfate 13.2 66.4 46.2 7.6b Sodium lauryl sulfate 46.3 13.0 9 67.0 48.2 15.0 12 63.2 Alkyl aryI sulfonate 4 60.8 48.8 16.0 Sodium kerylbenzenesulfonate 5.Ob 60.8 49.5 16.2 9 60.4 49.0 16.2 12 55.6 48.8 17.6 Alkyl aryl polyethylene glycol ether 4 52,O 48.2 18.4 p-Iso-octylphenoldecaethyleneglycol 6.5b 46.8 51.2 20.8 9 54.6 47.2 17.3 12 51.2 48.7 18.8 Alkyl olyethylene glycol thio ether 4 42.2 49.4 21,O ProBuct 5 5 . 8 ‘ ~ 41.2 50.1 21.5 9 45.0 48.5 20.1 12 43.2 49.1 20.7 a Work of adhesion and adhesion tension values on paraffin wax in ergs per sq om b Xbrm& p H of 0.4% solution.
( 7 ) Bancroft, W. D . , “Applied Colloid C h e m i s t r y , ” 3rd e d . , p . 363, S e w York, McGraw-Hill Book Co., 1932.
(8) Bikerman, J. J., “Surface Chemistry for Industrial Research,” p . 154, New York, Academic Press, Inc., 1948. (9) Bosanquet, C. H . , a n d H a r t l e y , H., Phil. M a g . , 42, 456 (1921). (10) Cooper, W.F., a n d N u t t a l l , W.H., J . Agr. Sci., 7, 219 (1915). (11) Freundlich, H., “Colloid a n d Capillary C h e m i s t r y , ” translated by H . S. Hatfield, New York, D u t t o n & Co., 1926. (12) H a r k i n s , W. D., a n d F e l d m a n , A, J . Am. Chem. SOC.,44, 2665 (1922). (13) H a r k i n s , W. D., and J o r d a n , H. F., Ibzd., 52, 1751 (1930). (14) M c B a i n , J. W., “Advances in Colloid Science,” Vol. I, edited by E. D. K r a e m e r , p , 101, X e w York, Interscience Publishers, Inc., 1942. (15) Mack. G. L., J . Phgs. Chem., 40, 159 (1936). (16) Mankowich, A. M,, ISD. ENG.C H E M . ,44, 1151 (1952). (17) Osterhof, H . J., a n d Bartell, F. E., J . Phys. Chem., 34, 1399 (1930). (18) Rideal, E. K . , “V7etting a n d Detergency” (Symposium of International Society of L e a t h e r Trades’ Chemists, British Section), 2nd ed., New York, Chemical Publishing Co., Inc., 1939. (19) Robinson, C., Ibid. (20) Snell, F. D., IND. ENC;. CHEM.,24, 76 (1932). RECEIVED for review August 2, 1952.
ACCEPTED August 31, 1953
