Polymerized Paired Ions as Polymeric Ionic Liquid-Proton Conductivity.

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Ionic liquids (ILs) offer unique properties but often lack structural integrity for practical applications.
• Stimuli-responsive materials are crucial for developing advanced sensors and energy storage devices.
• Developing novel proton conductors with high conductivity and stability is essential for fuel cells and electrochemical devices.

Purpose of the Study:

• To synthesize a new polymerized ionic liquid (PIL) using a stimuli-responsive ionic liquid surfactant.
• To investigate the proton conductivity and potential applications of the synthesized PIL in sensors and ultracapacitors.
• To explore the relationship between the ionic liquid's structure, stimuli-responsiveness, and proton transport properties.

Main Methods:

• Photopolymerization of a novel ionic liquid surfactant, ILAMPS, composed of 1-methyl-3-[11-(acryloyloxy)undecyl] imidazolium (IL) and 2-acrylamido-2-methyl-1-propanesulfonate (AMPS).
• Characterization of the resulting hygroscopic and highly polarizable polymerized ionic liquid resins.
• Measurement of proton conductivity, including the effect of doping with HPF6, and determination of activation energies for proton transport.

Main Results:

• Successful synthesis of a new polymerized ionic liquid with inherent stimuli-responsive properties.
• The PIL resins demonstrated high polarizability, indicating suitability for sensor design and ultracapacitor fabrication.
• Doping with HPF6 significantly increased proton conductivity (100-fold) at elevated temperatures (100-125 °C) and low humidity.
• Achieved lower activation energies for proton transport compared to Nafion under specific conditions.

Conclusions:

• The novel PIL exhibits promising characteristics for advanced electrochemical applications, including sensors and ultracapacitors.
• The stimuli-responsive nature of the ionic liquid contributes to enhanced proton transport mechanisms.
• This material represents a significant advancement in the field of proton-conducting polymers for energy applications.