Synthesis and microstructural studies of organogel for flexible electronic applications

Abstract

The increasing demand for flexible, wearable, and bio-integrated electronic devices has accelerated the development of soft and mechanically compliant materials capable of sustaining large deformations while maintaining electrical functionality. Conventional rigid electronic materials often exhibit mechanical incompatibility with soft substrates and biological tissues, limiting their applicability in flexible electronic systems. Conductive hydrogels and organogels have emerged as promising alternatives due to their tissue-like softness, flexibility, and ability to support ionic charge transport; however, their practical use is often restricted by poor mechanical strength and limited environmental stability. In this study, interpenetrating polymer network (IPN) hydrogels and organogels based on polyacrylamide (PAAm) reinforced with natural polysaccharides, namely pectin and gellan gum (GG), were successfully developed using a dual crosslinking and post-synthesis solvent displacement strategy. The combination of covalent crosslinking within the PAAm network and ionic coordination between calcium ions and the polysaccharide chains imparted enhanced mechanical strength, flexibility, and structural stability to the hydrogel systems. Subsequent solvent displacement with polyols, including glycerol and ethylene glycol, effectively transformed the hydrogels into organogels with significantly improved anti-freezing, anti-dehydration, and thermal stability. Comprehensive characterisation using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), swelling studies, and mechanical testing confirmed the formation of robust dual-network architectures and strong hydrogen-bonding interactions between the polymer networks and polyol solvents. The rheological analysis provided detailed insight into the viscoelastic behaviour and network stability of the gels. Mechanical evaluations demonstrated substantial improvements in tensile strength and elasticity, while anti-freezing and solvent-retention studies highlighted the superior environmental tolerance of the organogels. Ionic conductivity measurements over a wide temperature range revealed stable and efficient ion transport, including at sub-zero temperatures. Overall, the results demonstrate that PAAm-based polysaccharidereinforced IPN organogels offer a mechanically robust, environmentally resilient, and ionically conductive material platform, making them promising candidates for flexible electronics, wearable .sensors, and lowtemperature soft electronic applications.