Biophysics of Human Hair: Structural, Nanomechanical, and Nanotribological Studies - Hardcover

by Bharat Bhushan (Author)

Humanhairisananocompositebiological?ber. Maintainingthehealth, feel, shine, color, softness, andoverallaestheticsofthehairishighlydesired. Haircarepr- ucts such as shampoos and conditioners, along with damaging processes such as chemical dyeing and permanent wave treatments, affect the maintenance and groomingprocessandareimportanttostudybecausetheyaltermanyhairprop- ties. Nanoscalecharacterizationofthecellularstructure, mechanicalproperties, and morphological, frictional, andadhesive properties(tribologicalproperties)ofhair areessentialtoevaluateanddevelopbettercosmeticproductsandtoadvancethe understandingofbiologicalandcosmeticscience. Theatomic/frictionforcemic- scope(AFM/FFM)andnanoindenterhavebecomeimportanttoolsforstudyingthe micro/nanoscalepropertiesofhumanhair. Inthisbook, wepresentacomprehensive review of structural, nanomechanical, and nanotribological properties of various hairandskinasafunctionofethnicity, damage, conditioningtreatment, andvarious environments. Variouscellularstructuresofhumanhairand?nesublamellarstr- turesofthecuticleareidenti?edandstudied. Nanomechanicalpropertiessuchas hardness, elasticmodulus, tensiledeformation, fatigue, creep, andscratchresistance arediscussed. Nanotribologicalpropertiessuchasroughness, friction, andadhesion are presented, as well as investigations of conditioner distribution, thickness, and bindinginteractions. Tounderstandtheelectrostaticchargebuilduponhair, surface potentialstudiesarealsopresented. Thebookshouldserveasareferencebookonthebiophysicsofhumanhairand hairtreatments. TheresearchreportedinthisbookwassupportedbyProcter&GambleCo. in Cincinnati, Ohio, andKobe, Japan. IwouldliketothankCarmenLaTorrewhohad assistedinvariouspublicationsonhairresearch. Iwouldalsoliketothankmywife Sudha, whohasbeenforbearingduringthepreparationofthisbook. Powell, OH BharatBhushan November2010 v Contents 1 Introduction-Human Hair, Skin, and Hair Care Products. . . . . . . . . . . 1 1. 1 HumanHair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1. 1 TheCuticle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. 1. 2 TheCortexandMedulla. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. 2 Skin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1. 3 HairCare: CleaningandConditioningTreatments, andDamaging Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1. 3. 1 CleaningandConditioningTreatments: Shampoo andConditioner. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. 3. 2 DamagingProcesses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1. 4 OrganizationoftheBook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2 Experimental Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. 1 ExperimentalApparatuses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2. 2 ExperimentalProcedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2. 2. 1 StructuralCharacterizationUsinganAFM. . . . . . . . . . . . . . . . 26 2. 2. 2 SurfacePotentialStudiesUsingAFM-Based KelvinProbeMicroscopy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2. 2. 3 NanomechanicalCharacterizationUsingNanoindentation . . . 30 2. 2. 4 InSituTensileDeformationCharacterizationUsingAFM . . . 32 2. 2. 5 M

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This book presents the biophysics of hair. It deals with the structure of hair, its mechanical properties, the nanomechanical characterization, tensile deformation, tribological characterization, the thickness distribution and binding interactions on hair surface. Another important topic of the book is the health of hair, human hair and skin, hair care, cleaning and conditioning treatments and damaging processes. It is the first book on the biophysical properties of hair.