Synthesis of Sulfonated Polyphenylene Block Copolymers via In Situ Generation of Ni(0)

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Sulfonated polyphenylenes (sPP) are crucial for high-performance proton exchange membranes (PEMs).
• The synthesis of sPP block copolymers typically relies on expensive Ni(0) catalysts for Colon's cross-coupling reactions.
• There is a need for cost-effective synthetic routes to sPP block copolymers.

Purpose of the Study:

• To develop an economical in situ method for generating the Ni(0) catalyst for sPP block copolymer synthesis.
• To synthesize sPP block copolymers using the novel catalytic approach.
• To evaluate the performance of PEMs fabricated from these sPP block copolymers.

Main Methods:

• In situ generation of Ni(0) catalyst from an inexpensive Ni(II) salt using Zn and NaI.
• Colon's cross-coupling reaction utilizing neopentyl-protected dichlorobenzenesulfonates and oligo(arylene ether ketone).
• Synthesis of sPP block copolymers using NiBr2(PPh3)2 catalyst.

Main Results:

• Successfully synthesized sPP block copolymers with high molecular weights and comparable polydispersity to those made with pre-formed Ni(0) catalysts.
• Fabricated thin, transparent, and flexible PEMs from the synthesized sPP block copolymers.
• Achieved proton conductivities in the fabricated PEMs similar to those synthesized using the expensive Ni(0) catalyst.

Conclusions:

• The developed in situ Ni(0) generation strategy provides a cost-effective alternative for synthesizing sPP block copolymers.
• This method enables the production of high-performance PEMs with properties comparable to those from conventional methods.
• The strategy holds potential for broader applications in synthesizing multifunctional block copolymers.