• • The coaxial encapsulation strategy reduces mass loss to 2.5% after 60 days at 25 °C, and swelling rate to 1.5% after 60 days underwater, enabling long-term operational stability in humid or aqueous environments.
• • The sensor achieves a gauge factor (GF) of 1.705, indicating high strain sensitivity suitable for precise motion detection and wearable diagnostics.
• • Stable operation across -20°C to 120°C extends applicability to extreme thermal conditions, from cold-chain monitoring to high-temperature industrial settings.
• • The PDMS hydrophobic shell provides resistance to underwater and solvent environments, overcoming the dehydration and swelling failure modes of conventional hydrogel sensors.