Bioinspired microstructures of chitosan hydrogel provide enhanced wear protection.
basic_science · Level V
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- Record sourced from PubMed, PMID 29484334.
- Also identified by DOI 10.1039/c8sm00215k.
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Abstract
We describe the fabrication of physical chitosan hydrogels exhibiting a layered structure. This bilayered structure, as shown by SEM and confocal microscopy, is composed of a thin dense superficial zone (SZ), covering a deeper zone (DZ) containing microchannels orientated perpendicularly to the SZ. We show that such structure favors diffusion of macromolecules within the hydrogel matrix up to a critical pressure, σ<sub>c</sub>, above which channels were constricted. Moreover, we found that the SZ provided a higher wear resistance than the DZ which was severely damaged at a pressure equal to the elastic modulus of the gel. The coefficient of friction (CoF) of the SZ remained independent of the applied load with μ<sub>SZ</sub> = 0.38 ± 0.02, while CoF measured at DZ exhibited two regimes: an initial CoF close to the value found on the SZ, and a CoF that decreased to μ<sub>DZ</sub> = 0.18 ± 0.01 at pressures higher than the critical pressure σ<sub>c</sub>. Overall, our results show that internal structuring is a promising avenue in controlling and improving the wear resistance of soft materials such as hydrogels.