Effects of Counter Anions on AC and DC Electrical Conductivity in Poly(Dimethylsiloxane) Crosslinked by Metal-Ligand Coordination

Area of Science:

• Materials Science
• Polymer Chemistry
• Organic Electronics

Background:

• Flexible organic field-effect transistors (OFETs) require advanced elastic dielectric materials.
• Poly(dimethylsiloxane) (PDMS) is a promising base polymer, but its dielectric properties need enhancement for OFET applications.

Purpose of the Study:

• To investigate the AC and DC electrical conductivity of flexible PDMS polymers crosslinked with metal-ligand coordination.
• To analyze the impact of different metal ions (Ni2+, Mn2+, Zn2+) and halide salts (Cl-, Br-, I-) on PDMS dielectric properties.
• To evaluate the potential of these modified PDMS materials as gate insulators in OFETs.

Main Methods:

• Broadband dielectric spectroscopy was employed to analyze electrical conductivity.
• A series of PDMS polymers were synthesized using 2,2-bipyridine-4,4-dicarboxylic amide as a ligand and various metal salts.
• Temperature-dependent conductivity relaxation times were analyzed.

Main Results:

• Metal-ligand coordination increased dielectric permittivity in the order: neat PDMS < Ni2+ < Mn2+ < Zn2+.
• Electrical conductivity increased in the order: neat PDMS < Cl- < I- < Br-.
• Materials with chloride salts exhibited promising dielectric properties without significant loss of insulating behavior.

Conclusions:

• Flexible PDMS polymers crosslinked with metal-ligand coordination offer enhanced dielectric permittivity and tunable conductivity.
• These materials present a viable solution for developing flexible dielectrics for OFET gate insulators.
• PDMS modified with chloride salts are particularly suitable for OFET applications.