Force Spectroscopy Study on Poly(acrylamide) Derivatives:  Effects of Substitutes and Buffers on Single-Chain Elasticity

Abstract

Single-chain elasticity of two important poly(acrylamide) derivatives, poly( N, N ‘ -dimethylacrylamide) (PDMA) and poly( N, N ‘ -diethylacrylamide) (PDEA), was investigated by an atomic force microscopy (AFM)-based single molecule force spectroscopy (SMFS). SMFS revealed that the single chain of PDEA was stiffer than that of PDMA due to different bulky substitutes. It was also found from the SMFS study that the elasticity of PDMA and PDEA was enhanced in urea buffer solutions, probably due to hydrogen-bond interactions between urea molecules and the side groups of poly(acrylamide) derivatives.