Small-angle neutron scattering, which has not been extensively utilized for foam characterization, can provide important insights into the microstructure of surfactant-stabilized foam. Small-angle neutron scattering in combination with several other techniques was herein employed to determine the microstructure of foams stabilized by hydroxy group-containing (C 12 − EtOH-βAla) and hydroxy group-free (C 12 −Me-βAla) surfactants of the amino acid type. Hydroxy group introduction at the amide nitrogen had no effect on the foam film thickness (∼26 nm in both cases) but increased the foam stability and suppressed draining, as hydrogen bonding between hydroxy groups and carboxylate ions increased the foam film strength. Moreover, the obtained foam films were shown to contain micelles identical to those in the bulk solution.

To establish the evaluation method of tactile sensation of human hair, coincidence measurement of motion analysis and load measurements during hair brushing and finger combing were performed. Change in load profile from root to tip of hair by application of hair care products was examined. Change in the maximum load by hair damage and treatment and its correlation with sensory evaluation were also discussed. It was shown that the load during hair brushing which is considered to reflect the frictional property of human skin surface is useful to evaluate tactile feelings of human hair.

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