Room-Temperature Viscoelastic Liquid Semiconducting Block Copolymer with Mixed Ionic-Electronic Conduction.

Area of Science:

• Materials Science
• Polymer Chemistry
• Bioelectronics

Background:

• Conventional conjugated polyelectrolytes (e.g., PEDOT/PSS) offer mixed ionic-electronic conductivity but lack the necessary softness for bioelectronic applications, exhibiting high stiffness (GPa range).
• Soft ionic conductors like ionogels are highly deformable but do not possess the semiconducting properties required for signal transduction and amplification in bioelectronic devices.

Purpose of the Study:

• To develop a novel liquid semiconducting block copolymer (L-SBCP) that combines tissue-like softness, high deformability, and semiconducting properties for bioelectronic applications.
• To enable solvent-free processing of advanced semiconducting materials for seamless integration with biological systems and devices.

Main Methods:

• Synthesized a liquid semiconducting block copolymer (L-SBCP) by covalently linking a π-conjugated block with glycol side chains and a PEGMEMA bottlebrush acrylic block.
• Characterized the material's mechanical properties, demonstrating viscoelastic liquid behavior with deformability comparable to biological cells (1-100 Pa) and high stretchability (800%).
• Fabricated and tested an organic electrochemical transistor (OECT) using the L-SBCP, evaluating its electronic performance and cell viability.

Main Results:

• The synthesized L-SBCP is a phase-stable, free-flowing liquid with excellent deformability and stretchability, suitable for solvent-free processing via injection or vacuum filling.
• The L-SBCP functions as a p-type accumulation-mode OECT with a threshold voltage of +0.08 V, comparable to state-of-the-art soft semiconductors.
• The material demonstrated robust cell viability (>97%), indicating excellent biocompatibility for applications at cell-material interfaces.

Conclusions:

• The developed L-SBCP represents the first room-temperature liquid semiconductor with a combination of biorelevant softness, extreme deformability, electronic performance, and solvent-free processability.
• This new material composition and form factor opens opportunities for advanced bioelectronic signal amplification at cell-material interfaces.
• L-SBCP advances the field of semiconducting polymers and bioelectronic devices by providing a material that bridges the gap between electronic function and biological compatibility.