Increasing the Mechanical Stability of Polymer–Gold Interfacial Connection: A Parallel Covalent Strategy

Abstract

Thiol–gold (S–Au) chemistry has been widely used in coating and functionalizing gold surfaces because it is robust and highly efficient. However, recent studies have shown that the S–Au-based self-assembled monolayers can lead to significant instability under external mechanical loading (e.g., in a swelled polymer film). Such instability limits further applications of S–Au chemistry-based functional materials. Here, we report a surface-modifying procedure based on a parallel covalent strategy. By employing dendritic macromolecules as a “middle layer” between the gold surface and polymer, the interfacial connecting strength increased by at least 350% as revealed by atomic force microscopy-based single molecule force spectroscopy (AFM-SMFS). The ultimate cleavage structure is confirmed to be an amide bond by control SMFS experiments, fluorescent microscopy, and dynamic force spectroscopy. This study/concept paves the way to prepare stable stimuli-responsive polymer brushes on solid surfaces and study mechanophores with high force stability.

Single-Molecule Study Reveals Ion-Dependent Conformational Change and Nanomechanical Property of Crown Ether-Based Polymer

“…In recent years, atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) has overcome the limitations of many traditional methods, and it has been used to measure different supramolecular structures and interactions. − Kimura et al were the first to investigate the cation–crown ether complexation using SMFS. − However, Chen et al directly quantified the mechanical strength of a classical model of M n+ [15C5] 2 sandwich complexes under different local environments. The above studies deepen our understanding of cation–crown ether interactions.…”