Preparation of 3D printable polyvinyl alcohol based conductive hydrogels via incorporating k-carrageenan for flexible strain sensors

Multifunctional Conductive Double-Network Hydrogel Sensors for Multiscale Motion Detection and Temperature Monitoring

“…The changes in tensile strength, tensile strain, and toughness of the SBG hydrogel with different amounts of gelatin show a consistent trend of first increasing and then decreasing. As shown in Figure c,d, when the gelatin content reaches 10 wt%, the SBG hydrogel exhibits the highest tensile strength of 25.8 kPa, which can be stretched to 760% with a toughness of 106.54 kJ m –3 , which surpass the reported hydrogels (Figure e). ,,− Therefore, the SBG hydrogel with 4 wt% SH and 10 wt% gelation (labeled as S 4 BG 10 ) demonstrates outstanding mechanical performance and is chosen as the optimal formulation for the following tests. Especially, the elastic modulus (5 kPa) and toughness (106.54 kJ m –3 ) of the S 4 BG 10 hydrogel are comparable to the human skin of 10 3 –10 9 Pa and 100–12,000 kJ m –3 , respectively, which ensures a comfortable experience as it was used for wearable sensors …”

“…The results are much better than some of the reported hydrogels (Figure 5d). 16,31,37,39,47,48 Under the small strain, stretching causes an increase in inhomogeneity of the hydrogel network and a reduction in the cross-section area, which impedes the ion transfer and leads to an increase in resistance, whereas the free ions are still in contact with each other, resulting in a low GF (Figure 5c). With the increasing tensile strain, the ions separate from each other and the narrowing ion conductive pathway further increases the resistance, leading to a higher GF.…”

Three-Dimensional Printing of Hydrogels for Flexible Sensors: A Review

“…The 3D-printed strain sensor based on κ-carrageenan/Aam double network hydrogel demonstrated better strain sensitivity, having a GF of 0.63 at 1000% strain, making it ideal in human motion recognition. A borax, PVA, and κ-carrageenan (B-PVA/kC) hydrogel was printed into different 3D structures to fulfill the demand for pliable strain sensors in various forms [ 93 ]. The B-PVA/kC sensor precisely monitored large movements (fingers, wrist, elbow) as well as small movements (deep breathing) ( Figure 5 ).…”

“… Real-time variations in relative resistance during external compression, stretching, deep breathing, finger flexion, wrist movements, and changes in elbow motion using the B-PVA/kC 1 hydrogel sensor. Reproduced with permission [ 93 ]. Copyright © 2023 Elsevier B.V. …”

Preparation of Polypyrrole/Carbon Nanotubes Composite Cotton Fabric through In Situ Polymerization and Its Conductive Property

“…More importantly, using these metals is detrimental to the environment and may cause serious problems, such as cytotoxicity and genotoxicity. In contrast, the conductive polymer materials are polymerized on textiles with flexible, , conductive, mechanical, and electromagnetic properties. , Gong et al used graphene flakes and polypyrrole (PPy)-decorated fibers with Joule heaters and strain-sensing properties . The development of these complex composite conductive materials has improved the production of smart textiles and wearable sensors. , …”