fig3

Figure 3. Material design for sweat sampling in flexible sweat electronics. (A) Sponge substrates for sweat collection. Reproduced with permission^[49]. Copyright 2014, Wiley-VCH; (B) Hydrophobic/superhydrophilic textile for directed sweat transportation. Reproduced with permission^[50]. Copyright 2019, Wiley-VCH; (C) Filter paper-based sweat volume colorimetric platform. Reproduced under the terms and conditions of the CC BY^[52]. Copyright 2019, Author(s), published by Springer Nature; (D) PVA Hydrogel for sweat absorption. Reproduced with permission^[54]. Copyright 2021, American Chemical Society. PVA: Polyvinyl alcohol.