Programmed Polymer Folding with Periodically Positioned Tetrafunctional Telechelic Precursors by Cyclic Ammonium Salt...

Area of Science:

• Polymer Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Telechelic polymers with functional end-groups are crucial for controlled polymer architectures.
• Programmed polymer folding offers a pathway to complex macromolecular structures.
• Understanding the influence of functional group reactivity on folding is key to controlling polymer topology.

Purpose of the Study:

• To demonstrate a programmed polymer folding process using telechelic poly(THF)s.
• To investigate the formation of different polymeric constitutional isomers (manacle, 8-, θ-forms).
• To correlate polymer folding outcomes with the chemical reactivity of end-groups and interior positions.

Main Methods:

• Synthesis of tetrafunctional, linear telechelic poly(THF)s with pyrrolidinium salt groups.
• Electrostatic self-assembly followed by covalent fixation via ring-opening reactions.
• Characterization using 1H NMR, MALDI-TOF mass spectrometry, and SEC analysis.

Main Results:

• Doubly cyclized polymer products (IIa and IIb) were formed, yielding constitutional isomers.
• Polymer Ia, with equivalent linking group reactivity, preferentially formed the manacle-form isomer.
• Polymer Ib, with enhanced N-phenylpyrrolidinium end-group reactivity, predominantly formed the 8-form isomer.

Conclusions:

• Programmed polymer folding can be controlled by the spatial arrangement and chemical reactivity of functional groups.
• The formation of specific polymer folding isomers is directed by the polymer's structural and chemical characteristics.
• This work provides insights into the design of polymers with predictable folded architectures.