Enhancing the Self-Assembly of Step-Growth Polymers by Narrowing Their Molar Mass Distribution: A Dynamic...

Area of Science:

• Polymer Chemistry
• Materials Science

Background:

• Step-growth polymerization (SGP) traditionally yields polymers with broad molecular weight distributions (Đ) and poor nanostructure control.
• This limits the application versatility and performance of SGP-derived polymers compared to chain-growth polymers.

Purpose of the Study:

• To introduce asymmetric dynamic bond mediated polymerization (ADBP) as a method to overcome limitations in SGP.
• To achieve better control over molecular weight distribution and nanostructure in step-growth polymers.

Main Methods:

• Utilized a polymerization strategy involving asymmetric AA'-type dielectrophiles and B2-type dinucleophiles with a preferential reaction pathway.
• Controlled monomer conversion in two distinct stages: initial formation of dimers/trimers (p ≤ 0.6) followed by polymerization (p ≥ 0.6).

Main Results:

• Achieved significantly reduced molecular weight distributions (Đ < 1.5) compared to traditional SGP.
• Demonstrated improved molar mass control and enhanced nanostructure ordering in polymers.
• Synthesized polyurethanes (Đ = 1.2) with well-defined microphase-separated domains and superior mechanical properties.

Conclusions:

• ADBP offers a viable strategy for precise control in step-growth polymerization.
• The improved control translates to enhanced material properties, particularly in polyurethanes.
• This technique opens new avenues for designing high-performance polymers via SGP.