Subjective wet perception assessment of fabrics with different drying time

Abstract

Wet perception involves a complex neurobiological mechanism and it is a crucial factor affecting the wear comfort in daily life. A subjective wet perception assessment was conducted against wetted fabrics. The assessment method was set to demonstrate the sensation felt by the wearer in recovery period after light activities, and assumes that there is no further sweat secretion. Twenty participants participated in the assessment. Participants were presented with fabrics dried with different duration for simulating garments dry during recovery period. A new fabric driver was built to simulate body movements during wear. The driver drove specimens and reference fabrics on participants' forearms. The two-arm configuration of the fabric driver helps to enhance the reliability of assessment results. The participants were asked to give wetness rating on each sample in ratio scale. We conclude that log₁₀ of subjective wetness rating has linear relationship with drying time of fabric (DToF) and amount of water in fabric. A novel wetness factor (WF) is developed to quantify the effects of wet perception and exposure time induced by a drying fabric. WF is the area under curve of wetness rating against DToF. A smaller WF indicates that a user suffers less from wet sensation.

Keywords: comfort; drying; evaporation; fabric; subjective assessment; wet perception.

Figure 1.

Schematic diagram of two-arm fabric driver for subjective wetness assessment (cross section). The driver was synchronized to drive specimens and reference fabrics on both forearms of the participants.

Figure 2.

Ratio scale used for the wet perception assessment. In comparing wet perception of sample against reference, wetness rating is given in terms of percentage.

Figure 3.

Plots of amount of water in fabric at corresponding DToF (20 participants). Error bars show one standard deviation of uncertainty.

Figure 4.

Wetness (perception) rating of all assessed fabrics at various DToF (20 participants). (For example, label ‘RAY-16’ on x-axis refers RAY with DToF of 16 min; wetness rating of 1000 (per cent) means specimen is 10 times wetter than the reference; wetness rating of 50 (per cent) refers to wetness of the specimen being half that of the reference.)

Figure 5.

Wetness rating against DToF of CnP of participants A, B and C. Participant A sensed drop in wetness (R² ≥ 0.50 and a negative slope). Participants B and C do not sense change in wetness (R² < 0.50).

Figure 6.

Semi-log plots of wetness rating (average of Category (I) perception result) against DToF. Error bars show 1 s.d. of uncertainty. Linear best-fits are extrapolated to the DToF at fabrics completely dried.

Figure 7.

Wetness rating against DToF of Category (I) perception results. Wetness rating converges into a small range when fabrics approach dryness.

Figure 8.

Wetness rating against amount of water per unit volume in fabric of Category (I) perception results; y-axis is in log scale.