CMC STRUCTURE IN HAIR CUTICLE 13
atmosphere of 30 ° C and 50% relative humidity. A high-flux beam emitted from a
helical undulator (A. =0.083 nm) was focused with two mirrors laid horizontally and
vertically (8). In an experimental hutch, an X-ray beam 5 µm in diameter was produced
behind two pinholes, the first 5 µm in diameter and the second 100 µm in diameter. The
sample-to-detector distance was set at approximately 2.3 m. The reciprocal spacing (S)
was calibrated by a spacing of 4.894 nm for lead stearate. The X-ray diffraction profile
was recorded by a two-dimensional detector with an exposure time of 1 second, using an
X-ray image intensifier coupled to a cooled CCD camera (1024 x 1024 pixels). The
thickness of the �-layer and 3-layer was estimated using the method of Ohta et al. (7).
RESULTS
EFFECTS OF SOL VENT EXTRACTION ON HAIR DYEING
The effects of solvent extraction on the properties of hair dyeing are shown in Figure 1.
All of the solvents used in the present study elevated the extent of dyeing as compared
with that of non-extracted hair fibers. The differences seemed slight but have statistical
significance. There were differences in the extent of hair dyeing among the solvents used,
as hair subjected to extraction with hexane tended to become smaller.
DIFFRACTION FROM CUTICLE
An illustration of a SAXS diffraction pattern from a portion of the cuticle is shown in
Figure 2, in which signals vertical to the hair axis are tilted approximately 3° with an
46 ***
45
44
***
]..__,,,
+'43
C
Q.) .µ 42 X
Q)
b.O 41 -�
Q) 40 �
0
39
38
None MeOH Ace Hex Cl/Me
Solvent extraction
Figure 1. Effect of solvent extraction on hair dyeing properties. None: non-extracted. MeOH: extracted
with methanol. Ace: extracted with acetone. Hex: extracted with hexane. Cl/Me: extracted with a mixture
of chloroform and methanol (2:1). Mean ± standard derivation (n =8). :-itat1st1cal significance was analyzed
using a Dunnett test. *p 0.05, ***p 0.001.

14 JOURNAL OF COSMETIC SCIENCE
Micro-beam X-ray
(5 J1 m)
Diffraction
Hair fiber: 50 -.,100 J1 m
Figure 2. SAXS experiment.
equal tilt to the hair axis. This diffraction pattern shows the same profile that was
estimated to diffract from the cuticle CMC in previous reports (6,7).
A one-dimensional intensity profile produced from the diffraction pattern is demon-
strated in Figure 3. The intensity {I(S) x S4} was plotted versus reciprocal spacing (S)
according to an analytical method proposed by Ohta et al. (7). Reciprocal spacing (S) was
used to represent the index for the distance from the center of the diffraction pattern,
where S =1/d =(2/A) x sin(20/2), with A representing the wavelength of the X-ray, 20
the scattering angle, and d the repeat distance. Using this method, we estimated the
thickness of the �- and 8-layers in the CMC. The region of S 0.2 shown in Figure 3
contains four peaks of I(S) x S4 .The spans of the peaks differed among the hair samples,
which reflected differences in CMC structure. All intensity profiles analyzed in the
present study contained at least three peaks of I(S) x S4 in the region of S 0.2. The
analytical region (S 0.2) was considered wide enough for correct estimation of the
thickness of the �- and 8-layers.
EFFECTS OF SOL VENT EXTRACTION ON CMC STRUCTURE
SAXS experiments were performed using hair samples extracted with the four solvents.
The estimated values of thickness of the �- and 8-layers differed, based on the solvent
used, as shown in Figure 4. The thickness of the �-layer was decreased by extraction with
acetone and hexane, while it was not changed by extraction with methanol or chloro-
form/methanol. In addition, the thickness of the 8-layer was decreased by extraction