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Surface tension

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

As the test substance is a surfactant, the surface tension was used to determine the water solubility rather than the standard solubility.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The method used in this study to determine the Critical Micelle Concentration, is a drop tensiometer. The surface tension is determined by the software for various concentrations. The surfactant concentration after each measurement is automatically increased and the measurement procedure is repeated. Below the critical micelle concentration, the surface tension decreases when the concentration of surfactant increases. Once the CMC has been reached or exceeded, the surface tension remains constant. The critical micelle concentration is determine graphically by the slope change of the surface tension curve.

GLP compliance:

no

Type of method:

other: drop tensiometer

Surface tension:

30.4 mN/m

Temp.:

21 °C

Conc.:

0.036 g/L

Remarks on result:

other:

Remarks:

ST at CMC

Surface tension of water before measurement = 71.7 mN/m

Critical Micelle Concentration = 0.036 g/L

Surface tension at CMC = 30.4 mN/m

Increasement of surface tension after 1g/ L correspond to non solubility observed during preparation of solutions of concentration over 1g/ L. This behavior doesn’t impact the determination of the CMC of the sample.

Executive summary:

As the test substance is a surfactant, the CMC was determined rather than the standard solubility.

The drop tensiometer was used to measure the surface tension for different solution concentrations.

The Surface Tension was measured as 30.4 mN/m at the CMC of 0.036 g/L (36 mg/L).

Reference 2

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

march 2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

According to the standard method and it is not GLP; test item concentration differs

Qualifier:

according to guideline

Guideline:

other: EN14370 (2004)

Deviations:

no

GLP compliance:

no

Type of method:

ring method

Surface tension:

31.5 mN/m

Temp.:

23 °C

Conc.:

0.9 mg/L

CMC values according Ring-method EN 14370 (T=23.0ºC ± 0.5ºC)

sample	CMC (mg/L)
Solution 1 -measurement 1	0.953
Solution 1 -measurement 2	0.841
Solution 2 -measurement 1	2.100
Solution 2 -measurement 2	2.271

Conclusions:

The test item is surface-active in the test conditions.

Executive summary:

The static surface tension measurements on 2 samples with surface active agents LF 324 and LF 345 were performed according the Ring-method according EN 14370 (2004).

The surface tension of test item was measured as 31.5 mN/m at 23°C. (concentration 0.9 mg/L)

Description of key information

The test item is surface-active in the test conditions.

Key value for chemical safety assessment

Surface tension:

30.4

in mN/m at 20°C and concentration in mg/L:

36

Additional information

An experimental study (Processium 2019) was conducted on the substance to determine the CMC, using the drop tensiometer method. Despite the procedure does not follow the standard guideline, it was considered relevant for a surfactant, and reliable. The surface tension at CMC was retained as the key value.

A supporting study (Kruss 2004) was performed according to EN 14370 (2004), ring-method; test item ID is unclear (same constituents but different concentration than the registered substance, according to sponsor), but the result confirms the surface-active properties, with a similar value of 31.5 mN/m at CMC.