18-MEA DEPOSITION ON HAIR 33 METHODS Measurement of surface properties of the hair. The wetting forces of the hair were measured by the Wilhelmy method using a K100MK2 tensiometer (Kruss). Single hair fi bers were scanned over 3 mm at a velocity of 2 mm/min for the advancing mode. Dynamic contact angles were calculated from F = πdγcosθ where F is the wetting force, π is the circular constant, d is the diameter of hair, γ is the surface tension of water, and θ is the contact angle of the fi ber surface. The hair fi ber di- ameter was measured on the transverse section of each fi ber with a rotating fi ber diameter measurement system equipped with a laser (Kato Tech Co.) at 20°C and a relative humid- ity of 65%. The wetting force measurements were also performed at 20°C, 65% relative humidity (RH). Friction forces on the cuticle surface of the hair were measured using the KEF-SE friction tester (Kato Tech. Co., Ltd). The hair strands were mounted on a glass plate in such a way that all strands of the hair were separated and parallel to each other at 5-mm intervals. The test was conducted at a temperature of 20°C and a relative hu- midity of 65%. Quantitative analysis of 18-MEA. Semi-quantitative analysis of 18-MEA adsorbed on the outermost surface of the hair fi ber was measured by the TOF-SIMS IV instrument (ION- TOF GmbH, Germany) using 25-keV Au+ primary ions (average current, 0.3 pA pulse width, 100.0 ns repetition rate, 10 kHz) at high-spatial-resolution mode. The analysis Table I Formulation of Alkaline-Color Lotion 35% Hydrogen peroxide 10 28% Ammonia water 2.7 Ammonium bicarbonate 5.6 Cethyl trimethylammonium chloride 2.0 EDTA/2Na 0.5 Water Balance pH 9.0 Table II Formulation of Conditioners 1 2 3 4 5 6 (control) Stearoxypropyldimethylamine 2 — — — — 2 Dimethylaminopropylstearamide — 2 — — — — Stearyltrimethylammonium chloride — — 2 — — — Docosyldimethylamine — — — 2 — — Stearoxyhydroxypropyldimethelamine — — — — 2 — Benzyl alcohol 0.5 0.5 0.5 0.5 0.5 0.5 Stearyl alcohol 3 3 3 3 3 3 18-MEA 1 1 1 0.3 0.3 0.6 Lactic Acid 0.3 0.3 — — — 0.3 Water Balance

JOURNAL OF COSMETIC SCIENCE 34 area of 50 × 50 μm was randomly rastered by primary ions and was charge-compensated by low-energy electron fl ooding. The amount of 18-MEA adsorbed to the hair fi ber was measured using liquid chromatog- raphy/mass spectrometry (LC-MS, Agilent Technologies, Palo Alto, CA). Hair fi bers were immersed in chloroform/methanol (1:1 by volume) for 1 h at room temperature. The ex- tracts were dried using a nitrogen stream. The residues were then dissolved in chloroform/ methanol (1:9 by volume). In the system, a 1100 binary pump was connected to two mo- bile phases [M1, methanol/water (8:2 by volume) containing 100 mM ammonium acetate and 50 mM acetic acid and M2, methanol containing 100 mM ammonium acetate and 50 mM acetic acid] that were eluted at a fl ow rate of 0.2 ml/min. The mobile phases were pro- grammed consecutively, as follows: a linear gradient of M1 100–0% (M2 0–100%) be- tween 0 and 20 min, an isocratic elution of M1 0% (M2 100%) for 10 min, and an isocratic elution of M1 100% (M2 0%) from 30.1 to 40 min for column equilibrium (a total run time of 40 min). The injection volume was 5 μl. The column (L-column ODS 2.1-mm inner diameter × 150 mm Chemicals Evaluation and Research Institute, Tokyo, Japan) temperature was maintained at 40°C. ESI measurements in the mass spectrometer were performed with the following settings: polarity, negative heater temperature of nitrogen gas, 350°C fl ow of heated dry nitrogen gas, 11.01/min nebulizer gas pressure, 30 psi capillary voltage, -4000 V fragmenter voltage, 200 V. The selected ion monitoring (SIM) measurement in negative ion ESI was performed using the unit mass resolution mode. To detect deprotonated ions for 18-MEA, m/z = 325.2 was monitored. Measurement of surface properties of mica (A) Atomic force microscopy AFM images of the adsorbed layers on the mica surfaces were obtained using a Nanoscope IIIa Multi Mode AFM (Veeco Instruments, Santa Barbara, CA) with E-scanner. Tapping mode imaging was used to obtain the topography images of the absorbed membrane layers. To ensure that imaging the membrane caused no damage, the tapping force was set at the lowest possible level. The nominal spring constants of cantilevers are reported by the manufacturer to be 20-100 N/m, respectively. All images presented in this work were obtained reproduc- ibly over at least three spots on the sample surfaces. The images were acquired with a scan rate of either 0.5 or 1.0 Hz and were fl attened with a fi rst-order polynomial before analysis. The mechanical properties of the adsorbed membrane were analyzed by the AFM scratch- ing method. Scratching the adsorbed membrane was performed in contact mode with constant force, and a micro-fabricated tip made of silicon nitrate and a cantilever having a spring constant of 0.38N/m were used. First, an image (typically 5 μm × 5 μm) of the absorbed membrane was acquired then a smaller area (typically 1 μm × 1 μm) was scanned while loading the hard tip onto the surface. Following this, the scanning was repeated over the larger area. This method is hereafter called “scratching.” Thus, if the absorbed layer was strongly bound to the surface, it was harder to remove. (B) Angle-resolved X-ray photoelectron spectroscopy (ARXPS) ARXPS is a nondestructive method to obtain elemental and chemical-state information as a function of depth. ARXPS data was obtained using a Quantera SXM spectrometer (ULVAC PHI, Kanagawa) with a monochromatized Al K alpha X-ray source at 15 kV and 25 W. Survey spectra were recorded at a takeoff angle of 45° with pass energy of 280 eV by a cylindrical-mirror analyzer. Angle-resolved spectra were recorded at fi ve takeoff