Bioderived Composite Hydrogel Sensor: Combining Superstretchability, Moisture Retention, and Temperature Resistance for Strain and Temperature Visualization

Photonic crystals (PCs) exhibit the ability to adjust their microstructure and structural color in response to environmental stimuli and have been applied in optical manipulation and visual sensing, which showcase dynamic adaptability to changing conditions. In this study, a bioderived composite hydrogel sensor was prepared utilizing fish collagen, acrylamide, N-isopropylacrylamide, and PCs for the dual visualization of strain and temperature. Fish collagen derived from tilapia skin enhanced its mechanical properties with a 1846.29% tensile strain. Glycerol contributed to both moisturization and temperature stability, preserving the material's mechanical integrity even under extreme conditions of 60 and −53 °C. The reflection peak of the sensor exhibited blue shifts of 146 nm with 10% compression and 120 nm with 12% tensile strain. Additionally, the reflection peak experienced a blue shift of 45 nm as the temperature rose from 25 to 37 °C, and this shift remained stable even after 10 cycles. Moreover, the sensor's ability to visualize strain and temperature remained consistent even after a period of 30 days. Given its mechanical robustness, moisture resistance, temperature resilience, and durability, the bioderived composite hydrogel sensor stands as a viable choice for ongoing, prolonged monitoring of strain and temperature in wearable research studies.