60 JOURNAL OF COSMETIC SCIENCE
MATERIALS AND METHODS
All materials were purchased and used as received unless otherwise noted. Sodium
hydroxide (≥97%, 221465), Zein (Z3625), SLS (≥98.5%), calcium chloride (≥97%,
C4901), sodium chloride (≥99%, S9888), citric acid, potassium sorbate, sodium benzoate,
and deuterated water (99.9 atom %D, 293040) were purchased from Sigma (Missouri,
USA). SLES (Steol CS-330) and Sodium alkylbenzene sulfonic acid (Bio-Soft 101) were
purchased from Stepan (Illinois, USA) the alkylbenzene sulfonic acid was neutralized to
pH 7 with sodium hydroxide prior to use. OFS surfactants were prepared as solid powders
by a combination of propriety methods and those previously described.18 Cotton skeins
were purchased from Testfabrics (1203007 Pennsylvania, USA). Cocoamidopropyl betaine
powder purchased from Eazy Colors (South Yorkshire, UK) contained approximately 10
wt% sodium chloride, which was accounted for in all formulation salt loadings. Sodium
lauroamphoacetate (ColaTeric L-32) was purchased from Colonial Chemical (Pennsylvania,
USA). Dimethyl lauramide (Ninol CAA) and glyceryl caprylate/caprate (Mild GCC) were
purchased from Stepan. Aloe vera (200x, HUM-ALVE-02), hydroxypropyl starch (TEX-
HPST-01), hydroxyethyl cellulose (THK-HYCEL-01), and xanthan gum (THK-XTGM-01)
powders were purchased from Making Cosmetics (Washington, USA). SIPERNAT® 500LS
hydrated silica was purchased from Evonik (Pennsylvania, USA).
SURFACTANT ANALYSIS AND PROPERTY TESTING
Structural confirmation of sodium dodecanoyl methylfuran sulfonate surfactant purity was
provided by 1 H NMR analysis of a 0.05 M surfactant solution in deuterated water with
(trimethylsilyl) propionic acid internal standard on a Bruker AVance series spectrometer with
a 1 H frequency of 300 MHz. The SO
3 active content of the surfactant solid was determined by
potentiometric titration performed according to ASTM D4251 and found to contain 90–95%
SO
3 by mass, with the remainder of the composition primarily comprised of sodium sulfate.
Tensiometer measurements to determine surfactant critical micelle concentration were
performed with a Krüss Drop Shape Analyzer at ambient temperature. Ten aqueous
solutions of sodium dodecanoyl methylfuran sulfonate with concentrations ranging from
10–0.1 mmol had their surface tensions analyzed. The surface tension measurement
was taken when the drop volume was approximately 90% of detachment volume. A
minimum of three measurements per solution was used for reproducibility. Critical micelle
concentration (CMC) was calculated as the intersection between two lines of best fit to the
data of surface tension versus ln (surfactant concentration).
Ross-Miles foaming tests were conducted in an apparatus purchased from Wilmad
LabGlass (LG-3941-100), which consists of a temperature controlled glass receiver and a
200 mL glass pipet. A surfactant concentration of 0.25 wt.% aged at 49°C for 30 minutes
was used for testing. The receiver was kept at ambient temperature (∼23°C). 50 mL of the
test solution was rinsed along the walls of the receiver. Foam heights were measured to the
nearest millimeter at the time when 200 mL solution was emptied from the pipet into the
receiver followed by a subsequent measurement after 5 minutes had expired.
High shear foaming tests were performed in a Black and Decker 40 oz 10 speed blender at
the lowest setting with a measured blade rotation of 13,700 rpm. Each 0.1 wt% surfactant
solution was agitated for 30 seconds at this setting, after which time the initial foam height
was measured, followed by a subsequent measurement after 5 minutes had expired.

61 Oleo-Furan Sulfonates
Fabric wetting kinetic tests of the surfactants was tested according to ASTM D2281-10.
The tests took place inside a 500 mL graduated cylinder using a solution with a surfactant
concentration of 0.25 wt%. Testing did not begin until all the bubbles below the surface
had risen to the top. A skein was twisted into a figure eight and the top and bottom where
hooked. The top of the skein loop was cut with scissors and the skein was drawn through
the fingers in order to be compacted. Time measurements began when the skein and anchor
were released into the solution. Once the skein lost buoyancy and sank, the time was
stopped.
Hard water tolerance of surfactants was determined by preparing a 0.5 wt% solution of
each surfactant and titrating with a calcium chloride solution. If a precipitate formed after
titrant was added, the surfactant solution was allowed to mix for a minute to determine if
the solid re-dissolved. The calcium chloride concentration at which a persisting precipitate
formed was indicated as the hard water tolerance of the test surfactant.
Zein testing of surfactants to approximate dermal irritation were performed by adding 1 g
of Zein to 50 mL of a 0.5 wt% surfactant solution with a magnetic stir bar and stirring the
mixture at ambient temperature for 1 hour at 300 rpm. After this time, the insoluble Zein
remaining was filtered and dried overnight in a vacuum oven at 40°C. The mass of dried
insoluble Zein was used to calculate the percent Zein remaining compared to the starting
amount.
FORMULATION PROPERTY TESTING AND PERFORMANCE REVIEW
Formulation Preparation. To assure minimal water content, OFS surfactant, salt, and all
cosurfactants purchased and used as powders were dried in a vacuum over at 40°C for
24 hours prior to use. Liquid formulations featuring OFS were prepared according to the
following procedure.
The OFS surfactant, selected cosurfactant or emollient, and salt were combined in the desired
ratio, then added to water to achieve the target total surfactant loading. These ingredients
were agitated using a Vortex Genie-2T mixer to dissolve and provide a clear solution. If
needed, applying heating in the range of 30-40°C was found to hasten dissolving for higher
surfactant volumes. Next, ingredients to improve texture and skin conditioning properties
were added to the solution, such as aloe vera and hydroxypropyl starch. A hazy appearance
was noted with addition of some additives and emollients such as hydroxypropyl starch
for ingredient combinations deemed compatible in this report, this was observed to be a
stable suspension, and did not result in phase separation or formation of an inhomogeneous
precipitate. Preservatives, typically comprised of potassium sorbate and sodium benzoate,
were then added, with heating in the range of 30°C–40°C for up to 30 minutes as needed
to dissolve. The resulting solution was adjusted to the target pH between 4 and 6 with
addition of citric acid depending on the intended product format formulations intended for
use as body wash were adjusted to pH 4.5. Solid format (powder) formulations were prepared
using the same order of addition as was followed for the liquid format formulations, with the
omission of water in the preparation process. The combined solid ingredients were blended
together in a food processor and either hydrated directly for product testing or loaded into a
sachet, which was subsequently heat sealed to minimize moisture accumulation.
Viscosity measurements of formulations featuring OFS surfactants were measured with
a Brookfield Ametek rotational viscometer (DVEELVTJ0) equipped with a LV-1 spindle