Structure Elucidation of 2D Polymer Monolayers Based on Crystallization Estimates Derived from Tip-Enhanced Raman...

Area of Science:

• Materials Science
• Polymer Chemistry
• Spectroscopy

Background:

• Structural elucidation of 2D polymer monolayers with long-range order is a significant challenge.
• The slow pace of development in 2D polymer chemistry and synthetic 2D materials is hindered by this challenge.

Purpose of the Study:

• To present a novel method combining tip-enhanced Raman spectroscopy (TERS) with a random growth crystallization model.
• To overcome the limitations in analyzing the structure and order of 2D polymer monolayers.
• To determine the nature and conversion number of cross-links in novel 2D polymers.

Main Methods:

• Tip-enhanced Raman spectroscopy (TERS) for local spectroscopic information.
• A random growth crystallization model to interpret TERS data and infer global features.
• Application to two new 2D homopolymers and one new 2D copolymer.

Main Results:

• Successful determination of cross-link nature and conversion number (X) for new 2D polymers.
• High degrees of crystallinity (93.1% to 99.7%) were calculated, assuming random, in-plane growth.
• Mean radii of defect-free crystalline areas were found to be 3-15 nm for conversion numbers between 84% and 98%.

Conclusions:

• The presented method effectively analyzes the structure and order of synthetic 2D materials.
• The studied materials qualify as 2D polymers, suitable for fundamental and applied research.
• This approach offers a new pathway for research on covalent sheets and related 2D materials.