還元および熱処理により永久矯正処理された毛髪繊維の電子顕微鏡による研究

Abstract

A curing method for permanent hair straightening using thioglycolic acid (TGA) has been widely used for decade. On the basis of the chemical reactions occurring during the curing treatment and the conformational changes of-helical chains, the straightening mechanism has been proposed. However, the changes of the hair structure in supermolecular level have not been clarified so far. In this report, the effects of reduction and heat treatments on the morphological changes of hair were studied by transmission electron microscopy (TEM). The ultrathin cross sections of the untreated and cured hair samples stained with uranyl acetate and followed by lead citrate were subjected to TEM observations. It was found that the intact cuticle and cortex morphologies of the untreated hair were confirmed from the fact that the A-layer, exocuticle, and endocuticle with high TEM contrast were clearly observed in each layer of the cuticle and the ill-defined cortex morphology with a low contrast was observed due to weak reactions of the staining reagents to the cortex. On the other hand, it was revealed for the stained cured hair, that (i) the decrease in TEM contrast toward the cortex center reflects the decrease of reduction reaction of the cortex components resulting from the extent of diffusion of TGA into the fiber, (ii) many voids were produced on the cuticle layers due elution of the proteins contained therein, (iii) a fine morphology with a high contrast of the structure of the whorl-like macrofibril is resulted from the reactions of the staining reagents with carboxyl groups produced by the disruption of-crystallites, and (iv) deformation, disruption and melting of the-crystallites occur on the arrangements of microfibril + matrix structural units near the cell membrane complex (CMC).

Self-organisation and characterisation of hierarchical structures in trimethyl β-cyclodextrin nano-films

“…Subsequently, to develop the precursor film, the solution was spin-coated at 4000 rpm for 45 s onto a 2 Â 2 cm 2 Si(100) wafer that had been cleaned by washing with ethanol prior to spin-coating. 45 The pristine TMCD films were dried under vacuum at ambient temperature for 1 h. Subsequently, the sample was quickly transferred to a vacuum drying oven (SVD30P, Sansyo Co. Ltd, Osaka, Japan) which was preheated to the desired temperature. To avoid overshooting the annealing temperature, the pristine TMCD films were placed in a desiccator after the temperature in the desiccator become constant.…”

“…1(a)], the TMCD films with thicknesses ranging from 6 to 121 nm showed excellent homogeneities, as similarly observed in our previous studies. 45 In their PXRD profiles, no distinct diffraction peaks assigned to the formation of crystals were observed, clearly showing the noncrystalline structures of the films [ Fig. 1(b)].…”

“…[36][37][38][39][40][41][42][43][44] In addition, we recently found that TMCD exhibits excellent solution processability toward homogeneous nanofilms on Si(100) substrates by spin-coating from a chloroform solution. 45 The glass transition temperature T g of a variety of polymeric films changes with the film thickness because of the confinement effect. [46][47][48] However, the T g values for TMCD ultrathin films (42.4 nm thick) were detected at similar temperatures to those of TMCD bulk samples, 45 suggesting that the TMCD molecules in the ultrathin films may show behaviour similar to that in the bulk powder state.…”

“…45 The glass transition temperature T g of a variety of polymeric films changes with the film thickness because of the confinement effect. [46][47][48] However, the T g values for TMCD ultrathin films (42.4 nm thick) were detected at similar temperatures to those of TMCD bulk samples, 45 suggesting that the TMCD molecules in the ultrathin films may show behaviour similar to that in the bulk powder state. Because the crystallisation conditions in the bulk state were reported by Tsukushi et al, 39,40 self-assembly behaviour of TMCD via crystallisation in ultrathin films, even less than 200 nm thick, was expected to be achieved because TMCD can exhibit crystallisation behaviour in thin films similar to that in bulk.…”

“…In particular, X-ray reflectivity (XRR) can detect the thickness, roughness and electron density of films 49,50 and can be very useful to analyse thin films, including amorphous sugar nano-films. 45,51 Also, even for ultrathin films, conventional powder X-ray diffraction (PXRD) can detect diffraction when the crystallinity is high, although the use of a high power or a coherent beam is preferred if the structure is not destroyed by the intense radiation. The use of synchrotron radiation can readily overcome the difficulties caused by the low power of conventional X-ray sources.…”