Temperature as a moisture cue in haptics on hair.

A mechanism for giving a moisturized or dried-out feeling to hair was investigated. A two-step approach was conducted in order to elucidate the issue. First, we have reviewed previous studies that are related to the sensory perception of materials not only in cosmetic industry but also in other fields, such as textile and architecture industries, and established a hypothesis. Second, we have verified the hypothesis derived from the first step and identified the mechanism for the moisturized or dried-out feeling that people feel by measuring the heat transfer characteristic, q(max) . The results revealed that the moisturized or dried-out feeling that people feel at the moment of contact with hair was highly related to the temperature drop at the skin surface. The results also revealed that the moisturized or dried-out feeling strongly depends on the hair shape (meandering and diameter), surface damage and the water content of hair fibres which constitute the hair swatch. The moisturized feeling, however, was not related to the water content of hair fibres at a constant relative humidity (RH), as the differences in the water content of the hair fibres at a constant RH were too small for the recognition of the difference in the moisturized feeling.