Functionalization of Conductive Polymers through Covalent Postmodification

Area of Science:

• Materials Science
• Organic Chemistry
• Polymer Science

Background:

• Conducting polymers (CPs) are versatile materials with tunable electronic properties.
• Functionalization of CPs is crucial for tailoring their characteristics for specific applications.
• Existing research extensively covers polyaniline (PANI), polypyrrole (PPy), and polythiophene (PT).

Purpose of the Study:

• To review and describe methods for functionalizing preformed conducting polymers.
• To discuss the two primary approaches: direct reactions on polymer chains and reactions with substituted CPs.
• To highlight the property improvements achieved through CP functionalization.

Main Methods:

• Direct functionalization via electrophilic aromatic substitution (S_EAr) on reduced CPs.
• Direct functionalization via nucleophilic substitution (SN) on PANI and PPy.
• Direct functionalization via nucleophilic conjugate addition on oxidized CPs (PANI, PPy, PT).
• Indirect functionalization by using monomers with pre-attached reactive groups (e.g., for PT, poly(fluorene)).

Main Results:

• Electrophilic substitution occurs on the reduced forms of PANI and PPy.
• N-H groups in PANI and PPy are susceptible to electrophilic substitution.
• Nucleophilic conjugate addition is applicable to the oxidized forms of PANI, PPy, and PT.
• Indirect methods involving functionalized monomers are prevalent for PT and other CPs like poly(fluorene).

Conclusions:

• Diverse organic chemical reactions enable the functionalization of conducting polymers.
• Both direct modification of polymer chains and indirect methods using functionalized monomers are effective.
• Functionalization significantly enhances the target properties of various conducting polymers.