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
