Lignin reinforced hydrogels with multi-functional sensing and moist-electric generating applications

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Poly(vinyl alcohol) (PVA) hydrogels possess diverse applications but suffer from limited mechanical strength.
• Lignin, an abundant aromatic biopolymer from lignocellulosic biomass, remains largely under-utilized.
• Improving hydrogel mechanical properties and introducing new functionalities is crucial for advanced applications.

Purpose of the Study:

• To enhance the mechanical strength of PVA hydrogels using lignin.
• To impart pH-responsive characteristics to PVA hydrogels.
• To explore the potential of lignin-reinforced PVA (LRP) hydrogels in moisture-induced electricity generation.

Main Methods:

• Incorporation of lignin into the PVA hydrogel matrix.
• Characterization of mechanical properties, including storage modulus.
• Evaluation of ionic conductivity, strain sensitivity, and performance at low temperatures (-30 °C).
• Fabrication and testing of a moisture-induced electric generator using LRP hydrogel.

Main Results:

• LRP hydrogel achieved a maximum storage modulus of 83.1 kPa, significantly exceeding that of pure PVA hydrogel.
• The LRP hydrogel demonstrated excellent ionic conductivity, mechanical properties, and strain sensitivity, even at -30 °C.
• A moisture-induced electric generator fabricated with LRP hydrogel produced a voltage output of 226.6 mV.

Conclusions:

• Lignin effectively reinforces PVA hydrogels, enhancing mechanical strength and introducing pH responsiveness.
• The developed LRP hydrogels exhibit superior antifreezing, ionic conductive, and strain-sensitive properties.
• These eco-friendly hydrogels show promise for applications in flexible electronics, sensors, and self-powered devices.