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TLDR from the article: > Because the keratin softens when it is hydrated by the moisture secreted from the sweat pores, it requires many seconds for the contac

TLDR from the article: > Because the keratin softens when it is hydrated by the moisture secreted from the sweat pores, it requires many seconds for the contact area to increase to the value reached almost instantaneously with a soft material, such as a rubber.

zitterbewegung 9y ago
The most interesting thing from the bottom of the abstract. This mechanism might be used by our tactile sense to identify materials and has implications for the design of tactile displays.
daxorid 9y ago
This is interesting, yes, but it seems immediately ... odd to me. Do we use rubber to manufacture tires because the frictional coefficient between rubber and asphalt is established rapidly due to asphalt sweating? No, it's because the frictional coefficient is already rather high to begin with. Is this not the case with rubber-keratin as well? Why involve sweat when static friction is sufficiently explanatory?
- city41 9y ago
  They are talking about non rubbery surfaces > When encountering a smooth, stiff, and impermeable surface, such as polished metal or glass, the actual contact area is initially small as is the friction. Because the keratin softens when it is hydrated by the moisture secreted from the sweat pores, it requires many seconds for the contact area to increase to the value reached almost instantaneously with a soft material, such as a rubber.
  - euyyn 9y ago
    As compared to rubbery ones. > the value reached almost instantaneously with a soft material, such as a rubber
- tgb 9y ago
  The role of sweat appears to be to make the keratin in the finger softer and allowing more of it to contact the hard surface. This is unnecessary when contacting a rubber surface since the rubber surface is already soft. I.e. rubber makes the sweating unnecessary and hence works even against hard surfaces like non-sweaty keratin or asphalt.

zitterbewegung 9y ago

The most interesting thing from the bottom of the abstract. This mechanism might be used by our tactile sense to identify materials and has implications for the design of tactile displays.

daxorid 9y ago

This is interesting, yes, but it seems immediately ... odd to me. Do we use rubber to manufacture tires because the frictional coefficient between rubber and asphalt is established rapidly due to asphalt sweating? No, it's because the frictional coefficient is already rather high to begin with. Is this not the case with rubber-keratin as well? Why involve sweat when static friction is sufficiently explanatory?

city41 9y ago
They are talking about non rubbery surfaces > When encountering a smooth, stiff, and impermeable surface, such as polished metal or glass, the actual contact area is initially small as is the friction. Because the keratin softens when it is hydrated by the moisture secreted from the sweat pores, it requires many seconds for the contact area to increase to the value reached almost instantaneously with a soft material, such as a rubber.
- euyyn 9y ago
  As compared to rubbery ones. > the value reached almost instantaneously with a soft material, such as a rubber
tgb 9y ago
The role of sweat appears to be to make the keratin in the finger softer and allowing more of it to contact the hard surface. This is unnecessary when contacting a rubber surface since the rubber surface is already soft. I.e. rubber makes the sweating unnecessary and hence works even against hard surfaces like non-sweaty keratin or asphalt.