Abstract
We investigated a prototype of a strain sensor based on the layers of a bionanomaterial containing bovine serum albumin (BSA matrix) and multi-walled carbon nanotubes (MWCNT filler). The aqueous dispersion of 25 wt.% BSA/0.3 wt.% MWCNT was applied by screen printing onto flexible polyethylene terephthalate substrates. After drying the layers by laser irradiation (~970 nm), various parameters of the layers were controlled, i.e., resistance R, bending angle θ, number of cycles n, and measurement time. One measurement cycle corresponded to a change within the range θ = ±150°. The layers of the BSA/MWCNT bionanomaterial had dimensions of (15 ÷ 20) mm × (8 ÷ 10) mm × (0.5 ÷ 1. 5) µm. The dependences of resistance R on the bending angle θ were similar for all layers at θ = ±30, and the R(θ) curves represented approximate linear dependences (with an error of ≤ 10%); beyond this range, the dependences became nonlinear. The following quantitative values were obtained for the investigated strain sensor: specific conductivity ~1 ÷ 10 S/m, linear strain sensitivity ~160, and bending sensitivity 1.0 ÷ 1.5%/°. These results are high. The examined layers of the bionanomaterial BSA/MWCNT as a strain sensor are of particular interest for medical practice. In particular, strain sensors can be implemented by applying a water dispersion of nanomaterials to human skin using a 3D printer for monitoring movements (arms and blinking) and the detection of signs of pathology (dysphagia, respiratory diseases, angina, etc.).
Supplementary Materials
The following are available online at https://www.mdpi.com/article/10.3390/I3S2021Dresden-10115/s1.
Author Contributions
Conceptualization, L.P.I.; Formal analysis, S.V.S.; Investigation, A.Y.G., V.A.P., E.P.K. and D.V.T.; Methodology, A.Y.G., V.A.P., E.P.K. and D.V.T.; Project administration, L.P.I. and A.Y.G.; Resources, E.P.K. and V.A.P.; Supervision, L.P.I. and A.Y.G.; Validation, L.P.I., E.P.K., A.Y.G. and S.V.S.; Writing—original draft, L.P.I., A.Y.G.; Writing—review and editing, L.P.I., A.Y.G. and S.V.S. All authors have read and agreed to the published version of the manuscript.
Funding
Study was supported by the Ministry of Science and Higher Education of the Russian Federation No. 07503-2020-216 from 27 December 2019.
Conflicts of Interest
The authors declare no conflict of interest.
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