Abstract
Collagen films with proton conduction are a candidate of next generation of fuel-cell electrolyte. To clarify a relation between proton conductivity and formation of water networks in the collagen film originating from a tilapia’s scale, we systematically measured the ac conductivity, infrared absorption spectrum, and weight change as a function of relative humidity (RH) at room temperature. The integrated absorbance concerning an O–H stretching mode of water molecules increases above 60% RH in accordance with the weight change. The dc conductivity varies in the vicinity of 60 and 83% RH. From those results, we have determined the dc conductivity vs. hydration number (N) per unit (Gly-X-Y). The proton conduction is negligible in the collagen molecule itself, but dominated by the hydration shell, the development of which is characterized with three regions. For 0 < N < 2, the conductivity is extremely small, because the water molecule in the primary hydration shell has a little hydrogen bonded with each other. For 2 < N < 4, a quasi-one-dimensional proton conduction occurs through intra-water bridges in the helix. For 4 < N, the water molecule fills the helix, and inter-water bridges are formed in between the adjacent helices, so that a proton-conducting network is extended three dimensional.
Original language | English |
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Article number | 61 |
Journal | Journal of Functional Biomaterials |
Volume | 11 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2020 Sept |
Keywords
- Bio-electrolyte
- Biofuel cell
- Biomaterial
- Collagen
- Fuel-cell electrolyte
- Hydration
- Hydrogen bond
- Ionic conduction
- Proton conduction
- Water bridge
ASJC Scopus subject areas
- Biomaterials
- Biomedical Engineering