Charge density alterations in human hair fibers: an investigation using electrostatic force microscopy

Abstract

A new method for high-resolution analyses of hair surface charge density under ambient conditions is presented in this paper. Electrostatic force microscopy (EFM) is used here to analyze changes in surface charge density in virgin hair, bleached hair, and hair treated with a cationic polymer. The atomic force microscopy technique is used concomitantly to analyze morphological changes in hair roughness and thickness. The EFM images depict exactly how the polymer is distributed on the surface of the hair fiber. The EFM's powerful analytical tools enabled us to evaluate the varying degrees of interaction between the hair fiber surface charge density and the cationic polymer. The surface charge density and the polymer's distribution in the hair fibers are presented in the light of EFM measurements.

Hair fiber characteristics and methods to evaluate hair physical and mechanical properties

“…Hair is considered as a dead mater and it is only alive when it is inserted in the scalp (pilose follicle). When the thread emerges, it becomes dead matter although it appears to be growing since the fiber follows increasing its length by a speed of about 1.0 cm/month (Cade, 1995;Dias, 2004;Longo et al, 2006).…”

Eyebrow bleaching among females: a cross-sectional study

“…Participants reported that eyebrow bleaching was related to decreased or increased eyebrow hair density, which is most likely due to the oxidation reactions associated with bleaching. Bleaching causes chemical and electrical charge changes to the hair and its structure, which can increase or decrease the density of the hair 1,4 …”

In Vitro Methodologies to Evaluate the Effects of Hair Care Products on Hair Fiber

“…Atomic Force Microscopy (AFM) enables the acquisition of a wide range of information, because it provides many imaging possibilities for different types of samples [26].…”

“…AFM could be applied to get certain hair strain properties, such as Particle deposition over surface and affinity to incorporated ingredients in hair care products [20,24], structural and morphological changes [26,[28][29][30][31] as well.…”

“…Protein loss [11,12,[44][45][46][47][48]; Electrophoresis [13,25]; Scanning Electron Microscopy [5,[19][20][21][22]; Transmission Electron Microscopy [6,24,25]; Atomic Force Microscopy [7,26,[28][29][30][31]; Optical Coherence Tomography [8,33]; RAMAN spectroscopy [10,[32][33][34] Hair Shine-Gloss Diffuse reflectance spectrophotometry [14,33,43,46,50] Easy to comb Combing resistance [12,64,65] Strength properties Resistance to breakage [12,14,16,33,61,62] Photoprotection Photoluminescence spectroscopy [40][41][42][43] Long-lasting color Diffuse reflectance spectrophotometry [14,…”