Structural Characterization of a Covalent Monolayer Sheet Obtained by Two-Dimensional Polymerization at an Air/Water Interface

Abstract

This work describes a two-dimensional polymerization at an air/water interface and provides, for the first time, direct spectroscopic evidence for the kind of crosslinks formed and for the conversion reached in a covalently bonded monolayer sheet. This evidence was obtained through a combination of a variety of monolayer characterization techniques before and after transfer onto solid substrates, in particular by tip-enhanced Raman spectroscopy (TERS) and TERS mapping after transfer of both the monomer and polymer monolayer onto Au(111). This work is a major advance for the field of 2D polymers synthesized at the air/water interface as it, in principle, allows estimation of the crystallinity by percolation theory and the location of regions with defects.

Keywords: Raman spectroscopy; dimerization; interfaces; photochemistry; structure determination.