One Pot Photomediated Formation of Electrically Conductive Hydrogels

Area of Science:

• Materials Science
• Polymer Chemistry
• Bioelectronics

Background:

• Electrically conductive hydrogels are crucial for advanced bioelectronic devices.
• Photolithography for conductive hydrogels is challenging due to light absorption by conductive polymers, hindering scaffold photopolymerization.
• Existing methods often require multiple steps or additional photocatalysts.

Purpose of the Study:

• To develop a facile, one-step method for synthesizing photopatternable conductive hydrogels.
• To enable simultaneous photo-cross-linking of a polymer scaffold and in-situ polymerization of 3,4-ethylene dioxythiophene (EDOT).
• To create conductive hydrogels with suitable mechanical and electrical properties for bioelectronic applications.

Main Methods:

• Copolymerization of photo-cross-linkable coumarin-containing monomers with sodium styrenesulfonate to form P(SS-co-CoumAc).
• Simultaneous photo-cross-linking of the P(SS-co-CoumAc) scaffold and EDOT polymerization without external photocatalysts.
• Optimization of the monomer ratio ([SS]:[CoumAc]) for desired hydrogel properties.

Main Results:

• Achieved a strain at break up to 16% and electronic conductivity of 9.2 S m⁻¹ with an optimized [SS]:[CoumAc] ratio of 100:5.
• Demonstrated high-resolution photopatterning of conductive hydrogels into micrometer-sized structures.
• Successfully utilized the photopatterned conductive hydrogels as electrodes for stable surface electromyography (sEMG) signal recording.

Conclusions:

• The developed one-step synthesis offers a promising route for fabricating complex conductive hydrogel architectures.
• The novel photo-cross-linkable polymers combined with in-situ poly-EDOT polymerization facilitate rapid prototyping of bioelectronic devices.
• This approach enables the creation of custom interfaces between electronics and biological systems for wearable applications.