To investigate the penetration of polyethylenimine (PEI) into human hair, cross-sectional samples of white human hair treated with PEI were prepared. In particular, a novel method to analyze the diffusion behavior of PEI in human hair was developed, in which the PEI parts in the cross-sectional samples were dyed with orange II and the cross sections were examined at a wavelength of 487nm (λ
max of orange II) with a microspectrophotometer. In our method, the penetration of PEI into bleached human hair clearly increased with increasing treatment time, and with decreasing molecular weight. In addition, the diffusion pattern of PEI at pH11.1 displayed Fickian type characteristics. This suggests that the diffusion coefficient of PEI is essentially independent of PEI concentration. By calculating the diffusion coefficient from the PEI concentration profile, the diffusion coefficient of PEI (Mw: 300-600) was found to be the order of 10
-10 cm
2 /s.
抄録全体を表示