326 JOURNAL OF COSMETIC SCIENCE IMAGING CETAB'S CHARACTERISTIC POSITIVE IONS IN UNTREATED HAIR FIBERS (CONTROLS) To establish the presence of CET AB in the cross section of CETAB-treated hair fibers, the positive ions of C 3 H 8 N + at 58 m/z and C 19 H 42 N + at 284 m/z were imaged first in untreated hair fibers and will serve as reference images for comparison (Figure 1). The images in Figure 1 do not show any CETAB activity within the untreated hair fiber. IMAGING CETAB'S CHARACTERISTIC POSITIVE IONS IN CETAB-TREATED HAIR FIBERS In contrast to the control fibers, images of CETAB-treated hair fibers at mass numbers 58 and 284 (Figure 2a,b) clearly show that CETAB has penetrated into the fiber interior. The extent of penetration, however, varies from fiber to fiber. In some cases, the CET AB penetration is restricted to the fiber periphery (broad ring) (Figure 2a), while other fibers have been penetrated uniformly throughout the bulk of the hair-fiber (Figure 26). These differences in penetration and the amount of CETAB may be due to differences in fiber history and constitution. It is important to note that the similarity of images at the two different mass numbers, 58 and 284, in Figure 2a,b support the idea that these two ions come from fragments of CET AB. IMAGING CETAB'S CHARACTERISTIC NEGATIVE IONS IN THE CROSS SECTION OF UNTREATED HAIR FIBERS The negative ion image of CETAB at 79 m/z (Br-) in an untreated control hair fiber is shown in Figure 3. The 79 Br- image in untreated hair does not show much activity. IMAGING CETAB'S CHARACTERISTIC NEGATIVE IONS IN THE CROSS SECTION OF CETAB-TREATED HAIR FIBERS The 79 Br- ion image of the CETAB-treated hair fiber (Figure 4) once again shows partial to complete penetration of CETAB into the bulk of the hair fiber, as was observed in the positive ion imaging. Figure 1. Imaging the presence of two of the characteristic positive ions of CET AB (left: C3H8N+ at 58 m/z right: C 19 H42N + at 284 m/z) in the surface of the cross section of an untreated hair fiber (serving as control).
CATIONIC CONDITIONING COMPOUNDS 327 Figure 2. (a) Images ofCETAB's characteristic positive ions C,H8N+ at 58 m/z (left) and C 19 H/12N• at 284 m/z (right) in CET AB-treated hair-fiber cross sections clearly show broad peripheral penetration. (b) Images of CET AB's characteristic positive ions C ,,H8 N' at 58 m/z (left) and C 19Hli2 N+ at 284 m/z (right) in CETAB-treated hair-fiber cross sections clearly show complete penetration of CETAB throughout the fiber cross section. CHARACTERISTIC POSITIVE AND NEGATIVE IONS OF PQ-10 IN UNTREATED AND PQ-10-TREA TED HAIR While the low-molecular-weight CETAB could be detected within the hair-fiber cross section via its characteristic positive and negative ions, this study was not able co trace or identify the presence of the high-molecular-weight PQ-10 within the conditioner­ treated hair fiber. The positive and negative ion spectra as well as all images of PQ- 10-created hair could not be differentiated from those of the untreated control hair and, therefore, show no evidence of PQ-10 in the cross section of PQ-10-treated hair fibers. This is probably indicative of the lack of penetration of PQ-10 into the hair fiber. EFFECT OF CONDITIONER PENETRATION ON HAIR FATIGUE RESISTANCE Combing of hair can be linked to a process of fatiguing. For example, during combing, hair is repeatedly subjected to extension within the Hookean region. In fatiguing, chis
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