Are Electrografted Polymers Chemisorbed or Physisorbed onto their Substrate?

Abstract

Summary: AFM-based single-molecule force spectroscopy was used to evaluate the mechanical strength of the link between a polymer and the substrate onto which the polymer is electrografted. Poly(N-succinimidyl acrylate) was electrografted onto gold substrates and brought into contact with an aminothiol-functionalized AFM tip. Bridging of single polymer chains resulting from the strong coupling between the activated esters on the polymer and amine groups on the tip was investigated. We found that the link between the polymer and the gold substrate can withstand a force far beyond the force characteristic for physisorption on gold.