Dynamic Nuclear Polarization with Conductive Polymers

Area of Science:

• Materials Science
• Physical Chemistry
• Spectroscopy

Background:

• Low sensitivity in liquid-state nuclear magnetic resonance (NMR) limits its applications.
• Dissolution dynamic nuclear polarization (dDNP) enhances NMR sensitivity by polarizing nuclear spins.
• Current dDNP methods require cryogenic temperatures (<2 K) and complex instrumentation, hindering widespread adoption.

Purpose of the Study:

• To introduce organic conductive polymers, specifically polyaniline (PANI), as a new class of polarizing matrices for dDNP.
• To demonstrate hyperpolarization of nuclear spins using these conductive polymers.
• To explore the potential of chiral conductive polymers for spin-selective hyperpolarization.

Main Methods:

• Utilized polyaniline (PANI) as a polarizing matrix for dissolution dynamic nuclear polarization (dDNP).
• Investigated relayed DNP for hyperpolarizing 13C spins in a host solution within porous conductive polymers.
• Explored chirality-induced spin selectivity in conductive polymers for electron spin hyperpolarization.

Main Results:

• Achieved 1H hyperpolarizations up to 5% using PANI as a polarizing matrix.
• Successfully hyperpolarized 13C spins via relayed DNP in conductive polymer matrices.
• Demonstrated electron spin hyperpolarization close to unity in chiral conductive polymers without low temperatures or high fields.

Conclusions:

• Organic conductive polymers, such as PANI, are effective polarizing matrices for dDNP.
• Relayed DNP in conductive polymers enables hyperpolarization of target nuclear spins.
• Chirality-induced spin selectivity in conductive polymers offers a promising route for efficient, low-temperature, low-field DNP.